Hi Tara. Topic 1 is the foundation topic of 0680 and it is also the longest, so it is worth knowing up front what shape it is. It has two halves that look different but are marked in exactly the same way. The first half (1.1 to 1.3) is about solid resources — rocks, ores and minerals: where they come from, how we dig them up, what that does to a place, and how a country makes them last. The second half (1.4 to 1.6) is about energy resources — where fossil fuels came from, the alternatives, how each one actually turns into electricity, and what makes demand for energy go up.
Here is the thing that will earn you the most marks in this topic, and it has nothing to do with rocks. Look at how many objectives begin with the word “Discuss the benefits and limitations of…”. There are four of them in Topic 1 alone: 1.2.6, 1.3.4, 1.4.4 and 1.6.2. Those are the 6-mark and 8-mark questions. Cambridge is politically neutral and the mark scheme is built to reward a candidate who gives both sides properly and then makes a judgement. A candidate who writes six lines against mining and one line for it does not get 6 marks — she gets about 3, because half the mark scheme is untouched. So every time you meet a “discuss” table in this guide, learn it as a pair of columns, not as an opinion.
The second thing: the definitions in this topic are given to you word for word in the syllabus, which means they can be asked back word for word. Ore, permeability, finite resource, sustainable management of resources and fracking are all one-mark gifts if you have them exactly, and all one-mark losses if you paraphrase them into something vaguer. They are boxed in yellow throughout. Learn those five sentences before you learn anything else in Topic 1.
And the third: two things in here are ordered chains — the rock cycle and the formation of fossil fuels. Chains are marked step by step, in order. If you write the steps out of order you lose the sequencing marks even when every word is correct. So they are taught as chains and then drilled as chains.
The command word decides how much you write — learn these nine
Every question in 0680 opens with one of these, and each one is asking for a different shape of answer. Writing a good explanation when the paper said “state” wastes time you need later; writing a bare fact when it said “explain” caps you at one mark. Four of these are used constantly on Paper 2 and are easy to miss: identify, state, calculate and compare.
| Command word | What the answer looks like |
|---|---|
| State | A short fact or a definition, with no reason and no example. One line is a complete answer. If the syllabus gives you the wording — ore, permeability, finite resource, sustainable management, fracking — give it back word for word. |
| Identify | Pick the thing out of the source in front of you. This is the standard opener on a source-led question, and the answer is a name, a letter, or a single value read off a graph, a table or a map. Do not explain it and do not add a second answer as insurance — a wrong extra can cancel a right one. |
| Describe | Say what happens or what you can see, in order where there is an order. For a figure, describe the trend and quote figures from the source as you go. No reasons: the reasons belong to explain. |
| Explain | Give the reason. Aim to get the words because and so that into every explain answer — if neither word fits anywhere in what you have written, you have probably described instead. |
| Calculate | Work out a number. Show the working on its own line, and keep the unit with the answer. For a percentage change, divide by the starting value. Percentage points (34 − 22 = 12) are not the same thing as a percentage change (12 ÷ 22 = 55 %). |
| Compare | Both things in the same sentence, with similarities and differences, and figures where the source gives them. “P generates 80 % from fossil fuels whereas R generates 8 %” is a comparison. Two separate paragraphs, one about P and one about R, are two descriptions, and comparison marks are usually reserved for the linking word — whereas, compared with, both. |
| Suggest | Apply what you know to a situation you have not met before. There is no single expected answer; anything sensible that fits the context and uses the material counts. This is the AO3 skill, and it is what Paper 2 is mostly made of. |
| Discuss | Two columns — benefits and limitations — then a judgement that says who gains, who bears the cost, and over what timescale. A one-sided answer leaves half the marks untouched however well it is written. |
| Evaluate | The highest of the nine. Weigh the evidence on both sides and reach a supported judgement. What is being marked is the weighing, not which side you land on. |
1.1 Formation of Rocks
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▶ Watch: rocks and the rock cycle
Opens on YouTube in a new tab. The first three are badged IGCSE 0680 but follow the old chapter numbering; the last three are general science, not 0680 lessons. None of them covers 1.1.3 or 1.1.4 — permeability, porosity and the permeable/impermeable classification. That part of the sub-topic is on the page above and nowhere in this list. The syllabus, not a video, decides what is examinable.
Three families, three ways of being made
Every rock on Earth belongs to one of three families, and the family name tells you how it was made rather than what it looks like. That is the useful way to hold it: igneous rocks froze from molten rock, sedimentary rocks were stuck together from bits, metamorphic rocks were changed in the solid state by heat and pressure. Cambridge names seven rocks and only seven, so you can afford to know each one properly.
Igneous: granite and basalt
Igneous rocks form when molten rock cools and crystallises. The single fact that carries the marks is that crystal size records cooling rate. Slow cooling gives the atoms time to arrange themselves into big crystals; fast cooling freezes them before they can, so the crystals are tiny.
Granite forms when magma cools slowly, deep underground, insulated by the rock above it. The result is large, easily visible interlocking crystals — you can see the individual pink, white and black grains with the naked eye. Because the crystals interlock, granite is hard, strong and impermeable, which is why it is quarried for building stone, kerbstones and worktops.
Basalt forms when lava cools quickly at the Earth's surface, after a volcanic eruption, in contact with air or water. The crystals are so small you need a lens to see them. Basalt is dark, dense and also impermeable, and it is quarried and crushed for road aggregate. Basalt is the rock of the Deccan Traps, which is most of the plateau under Karnataka and Maharashtra, so you are standing on the exam example.
Granite or basalt? Ask one question
Big crystals means the rock cooled slowly, deep down: granite. Small crystals means it cooled quickly, at the surface: basalt. If a question shows you a photograph or describes crystal size, that one sentence is the whole answer, and the “because it cooled slowly/quickly” is where the explain mark lives.
Sedimentary: limestone, sandstone and shale
Sedimentary rocks are made from sediment — loose particles — that settles in layers, usually under water, and is then squeezed and glued into solid rock. Because they are built in layers you can often see the bedding, and because the particles never perfectly fill the space between each other, most sedimentary rocks contain pore spaces. Hold on to that: it is why 1.1.3 and 1.1.4 exist.
| Rock | What it is made from | How it forms |
|---|---|---|
| Limestone | Calcium carbonate, mostly from the shells and skeletons of dead marine organisms | Shells settle on a warm shallow sea floor, build up over millions of years, and are compacted and cemented into rock |
| Sandstone | Sand grains, mostly quartz, eroded from older rocks | Sand is transported by rivers or wind, deposited in layers, then compacted and cemented by minerals crystallising between the grains |
| Shale | Very fine clay and mud particles | The finest particles settle only in still water, and are compacted so tightly that almost no pore space is left between them |
Notice that shale is made of the smallest particles and is the odd one out of the three — and it is the odd one out again in 1.1.4, and again in 1.6, because fracking is done in shale. That is not a coincidence: the tiny flat particles pack together so tightly that gas trapped inside cannot escape, which is exactly why the gas is still there and why you have to fracture the rock to get it.
Metamorphic: marble and slate
Metamorphic rocks are existing rocks that have been changed by heat and pressure without melting. That last phrase matters. If it melted it would be igneous. Metamorphism happens deep underground, where rock is buried under kilometres of other rock, or where it sits next to a body of hot magma.
- Marble is metamorphosed limestone. Heat and pressure destroy the fossils and shells and recrystallise the calcium carbonate into an even mass of interlocking crystals. That is why marble is uniform, hard, and takes a polish — and why the fossils that were in the limestone are gone.
- Slate is metamorphosed shale (or mudstone). Pressure applied from one direction rotates the flat clay particles until they all lie the same way, which is why slate splits into thin flat sheets. That property is called cleavage and it is the reason slate is quarried for roofing.
The pairing they ask for
limestone → marble and shale → slate. Sedimentary parent, metamorphic child. A very common question is “name the rock from which marble is formed” for one mark, followed by “describe the conditions required” for two — and the two marks are high temperature and high pressure, not “it gets squashed”. Say both, and say that the rock does not melt.
1.1.2 The rock cycle — an ordered chain
The rock cycle is the one diagram in Topic 1 you should be able to draw from memory, because a question that hands you a blank cycle with three or four boxes missing is a standard opener. The syllabus names eight processes and they are the only eight you need: weathering, erosion, transportation, deposition, sedimentation, compaction, cementation and crystallisation.
The rock cycle. The eight processes the syllabus names are the ones written on the arrows, plus uplift, melting, and heat and pressure, which link them.
The eight processes, in the order they happen
| # | Process | What is actually happening |
|---|---|---|
| 1 | Weathering | Rock is broken down in place by rain, frost, temperature change, plant roots or chemical attack. Nothing moves yet. This is the step most candidates confuse with the next one. |
| 2 | Erosion | The loosened fragments are picked up and worn away by moving water, wind, ice or gravity. Erosion involves movement; weathering does not. |
| 3 | Transportation | Rivers, wind, glaciers and waves carry the fragments away. The further they travel the smaller and rounder they get. |
| 4 | Deposition | When the water or wind slows down it can no longer carry the load, so the particles are dropped — the heaviest first, the finest last and furthest out. |
| 5 | Sedimentation | The dropped particles settle out and build up in layers on a sea, lake or river bed over long periods. |
| 6 | Compaction | The weight of the layers above squeezes the lower layers, pressing the particles together and forcing out the water between them. |
| 7 | Cementation | Minerals dissolved in the remaining water crystallise in the gaps and glue the particles together. Now it is a sedimentary rock. |
| 8 | Crystallisation | Somewhere else in the cycle, molten rock cools and its minerals grow into interlocking crystals, forming igneous rock. Slow cooling, big crystals; fast cooling, small ones. |
Seven letters for the sedimentary chain
W E T D S C C — Weathering, Erosion, Transportation, Deposition, Sedimentation, Compaction, Cementation. “We Eat Tea, Drink Some Cold Coffee.” The eighth process, crystallisation, is not part of that chain at all — it belongs to the igneous branch, and putting it in the sedimentary sequence is a classic wrong answer.
Weathering is not erosion
This distinction is tested almost every year. Weathering breaks rock down where it stands. Erosion removes the pieces. Frost splitting a boulder on a mountainside is weathering. The stream carrying the splinters downhill is erosion followed by transportation. If a question gives you two marks for “describe the difference”, the second mark is almost always the word in situ or the phrase without movement.
Worked example
Sandstone is found on a cliff several hundred kilometres from the mountain range whose granite it came from. Describe the sequence of processes that formed the sandstone, starting from the granite. [5]
How to read the marks
Five marks, and the command word is describe with the word sequence in it. That is five named processes in the correct order. You do not need to explain any of them; you need to name them and get the order right. Write them as a numbered list so the examiner can see the order.
The answer
1. The granite is broken down in place by weathering. 2. The loose fragments are removed by erosion. 3. They are carried hundreds of kilometres by a river — transportation — becoming smaller and rounder as they go. 4. Where the river slows, the sand grains are dropped: deposition, and they settle in layers on the sea bed (sedimentation). 5. Burial squeezes them together (compaction) and dissolved minerals crystallise between the grains to glue them (cementation).
weathering → erosion → transportation → deposition/sedimentation → compaction → cementation
1.1.3 Permeability — a definition to learn word for word
Learn this exactly
Permeability is the ability of water to pass through the pore spaces of rock and soil.
Two words in that sentence are doing the work: water and pore spaces. If you write “permeability is how easily water goes through a rock” you may be given the mark, but if you write “permeability is how hard a rock is” or “how much water it holds” you will not. Holding water is porosity; letting it through is permeability.
Why does the syllabus care? Because permeability decides where groundwater goes, which decides where aquifers form, where wells work, where a landfill will leak and where a reservoir can be built. It comes back in Topic 3 when you meet water supply, and it comes back in 1.6, where the fact that shale is impermeable is the entire reason fracking exists as a technique.
1.1.4 Classifying the seven rocks
| Permeable — water passes through | Impermeable — water does not pass through |
|---|---|
| Most sedimentary rocks: limestone and sandstone. Sandstone has connected pore spaces between its rounded grains; limestone lets water through its joints and cracks, and the water slowly dissolves it, opening the gaps wider. | Igneous (granite, basalt) and metamorphic (marble, slate), because interlocking crystals leave no connected gaps. Plus some sedimentary rocks: shale, whose clay particles are so fine and so flat that they pack with almost no connected pore space. |
Do not write “all sedimentary rocks are permeable”
The syllabus says most sedimentary rocks, and it names shale as the exception in the same breath. That single exception is worth remembering because it is the one they test, and because shale is the fracking rock. If you are asked to classify shale, the answer is sedimentary but impermeable.
Source AFigure 1.1A — the rock cycle with four labels removed
Objective 1.1.2 says describe and interpret the rock cycle. Describing it is reciting the eight processes; interpreting it is being handed a cycle with parts missing and working out what belongs where. This is the interpreting half, and it is the part Paper 2 asks for.
Write every part out before you open the model answer. Reading a model answer you have not attempted teaches you almost nothing.
Source A — part (a)
In Figure 1.1A, arrow W leads from rock at the surface to box A. Which process is arrow W?
Arrow W starts at rock that is still in place, so the process acting on it must be the one that does not move anything: weathering. Erosion is what carries the loosened pieces away afterwards. B and D both belong further round the cycle, after the sediment has been buried, and C belongs on the igneous branch entirely.
Source A — part (b)
Which label has been removed from box B in Figure 1.1A?
Box B sits directly below the layers of sediment and directly above the box reached by heat and pressure, so it has to be the sedimentary rock. Trace the arrows rather than guessing: whatever comes out of compaction and cementation is sedimentary, and whatever heat and pressure then act on becomes metamorphic. D is the label for box A, one step earlier.
- (c)Name, in the correct order, the processes shown by arrow X and then by arrow Y. [3]
- (d)A core taken at the sea bed site shows a mudstone layer 12.0 m thick. The accumulation rate measured there is 0.60 mm per year. Calculate how long that layer took to build up. Show your working. [2]
- (e)Explain why the rock in box B is more likely to be permeable than the rock in box C. [3]
- (f)Suggest one reason why the rock in box C is unlikely to contain a fossil in its original shape. [2]
Model
Model answer — Figure 1.1A, parts (c) to (f)
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(c) The two arrows, in order
Arrow X carries loose fragments from the land to a sea bed, so it is transportation, then deposition, then sedimentation — carried by the river, dropped when the water slows, then settling and building up in layers. Arrow Y turns those layers into rock, so it is compaction, then cementation — the weight above squeezes the layers and forces the water out, then minerals dissolved in the remaining water crystallise in the gaps and glue the grains together. Order is marked, so write them as a sequence, not as a list.
(d) The calculation
Convert first, because the two figures are in different units. 12.0 m = 12.0 × 1000 = 12 000 mm. Then time = thickness ÷ rate = 12 000 ÷ 0.60 = 20 000 years. Write the conversion line down: in a 2-mark calculation one mark is usually for the method and one for the answer, so a bare number with no working can only score one even when it is right.
(e) The explanation
Box B is sedimentary rock, built from grains stuck together by cement, and the spaces between those grains stay connected, so water can pass through from one pore to the next. Box C is metamorphic, formed by heat and pressure, which forces the minerals to grow into each other as interlocking crystals, so there is no connected pore space for water to move along. One honest caution: most sedimentary rocks are permeable, not all — shale is the named exception.
(f) The suggestion
Box C is reached through heat and pressure. Those conditions recrystallise the minerals and deform the rock, so any shell or bone shape that was there in the parent rock is squashed, stretched or destroyed. Marble is a good example: it was limestone, which is full of fossil shells, and after metamorphism the shells have gone.
Checkpoint 1.1
Answer, then read the explanation even when you were right.
Your Score
0 / 11
Question 1
A rock sample has large interlocking crystals that are easy to see without a lens. How did it most likely form?
Large crystals mean slow cooling, and slow cooling means the molten rock was insulated at depth — that is granite. A gives the opposite condition and would produce basalt, with crystals too small to see. B and D describe sandstone and limestone, which are made of grains and fragments stuck together, not of crystals that grew into each other.
Question 2
Which pair correctly matches a metamorphic rock with the rock it formed from?
Both metamorphic rocks named by the syllabus have sedimentary parents: limestone becomes marble, shale becomes slate. The other three options all pair at least one igneous rock as a parent, and although igneous rock can be metamorphosed in reality, these are not the routes 0680 asks for. Fix the pair by size: the fine-grained parent (shale) gives the fine-grained, splittable child (slate).
Question 3
Which statement correctly distinguishes weathering from erosion?
The whole distinction is movement: weathering acts in situ, erosion carries the pieces away. A invents a location rule that does not exist. B splits the agents up wrongly — wind and water both do both jobs. D is a right-idea-wrong-place answer: chemical weathering really can form new minerals, but erosion has nothing to do with making igneous rock, which requires crystallisation from a melt.
Question 4
Which sequence of processes forms sedimentary rock from loose particles on a sea bed?
The particles settle in layers, the weight above squeezes them, then dissolved minerals glue them. A is that order. D and B both smuggle crystallisation into the sedimentary chain, and crystallisation belongs to the igneous branch. C is the chain written backwards, which is a surprisingly common slip when you are working fast — read the first word of each option before anything else.
Question 5
Which definition of permeability matches the syllabus wording?
A is the syllabus definition and you should be able to write it without thinking. B defines how much water is held, which is porosity, not permeability — a rock can be porous and still impermeable if the pores are not connected. C is describing resistance to weathering. D is describing chemical weathering or leaching, which is a different idea again.
Question 6
Which of these rocks is sedimentary but classified as impermeable?
Shale is the exception the syllabus names: sedimentary, but the clay particles are so fine and flat that almost no connected pore space survives compaction. A and B name the two permeable sedimentary rocks, and the reasons given for them are correct reasons for permeability, not against it. C is impermeable and its reason is correct, but slate is metamorphic, so it does not answer the question asked.
Question 7
Basalt and granite are both igneous. Why do they look so different?
Cooling rate controls crystal size, and crystal size is the visible difference. A describes metamorphism, which by definition would stop them being igneous. C describes a sedimentary process — deposition sorts particles by energy, but igneous rock is not deposited. D is a trap for anyone who has stopped reading: igneous rock froze from a melt, so it cannot contain fossils.
Question 8
A layer of limestone lies directly on top of a layer of shale. Rain falls steadily on the limestone. What happens to the water?
Limestone is permeable and shale is impermeable, so water infiltrates the upper layer and is stopped at the boundary, which is exactly how a spring line forms. A treats limestone as impermeable, which it is not. C treats shale as permeable, which it is not. D reverses the two rocks completely — the tight shale is the barrier, not the store.
Question 9
A river slows down as it enters a lake and can no longer carry its load. Which process is happening?
Deposition is the moment the carrying agent loses energy and drops what it was carrying, heaviest particles first. Transportation is the stage just before, while the load is still being carried, and the two are separate named processes in 1.1.2, so a sequence answer must contain both. Compaction happens later, after burial, and weathering happens right at the start.
1.2 Extraction of Rocks, Ores and Minerals
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▶ Watch: extraction and its impacts
Opens on YouTube in a new tab. The first three are badged IGCSE 0680, following the old chapter numbering; the last three are general science chosen for a single objective each. Nothing here works through the eight decision factors in 1.2.3 one by one, so read that table on the page rather than expecting a video to give it to you.
1.2.1 What an ore is
Learn this exactly
An ore is rock containing minerals and metals.
Short enough that there is no excuse for losing the mark. What you must not do is add your own economics to it — you may have read elsewhere that an ore is rock from which a metal can be extracted “profitably”. That is a fine idea, and it belongs in 1.2.3 where cost and profit are a factor in the decision to extract, but it is not the definition 0680 gives.
The chain is worth keeping straight. A mineral is a naturally occurring solid with a definite chemical composition — quartz, calcite, haematite. A rock is a mixture of minerals. An ore is a rock that happens to contain enough of a useful mineral or metal to be worth digging up. The proportion of useful metal in the ore is called the ore grade, and it comes up again in 1.2.3.
1.2.2 Three ways of getting it out
The syllabus gives you three families of extraction method, and the exam question is nearly always “describe” or “suggest which method is suitable and why”. The deciding factor is almost always how deep the deposit is.
| Family | Named methods | How it works and when it is used |
|---|---|---|
| (a) Surface extraction | opencast, open-pit, open-cut, strip mining | Used when the deposit lies at or near the surface. The soil and rock lying above the deposit — the overburden — is stripped off and the deposit is dug out from the open air. Opencast, open-pit and open-cut are three names for the same idea — working the deposit from an open excavation at the surface instead of from tunnels — and Cambridge uses them interchangeably, so a paper that says “open-cut” is asking about the method you have learned as open-pit. Open-pit works downwards in a series of benches to make a deep bowl; strip mining removes one long strip at a time and dumps the overburden into the strip already worked. Cheap per tonne, fast, safer for workers, but it clears a large area of land. |
| (b) Subsurface extraction | deep mining, shaft mining | Used when the deposit is too deep for the overburden to be worth removing. A vertical shaft is sunk and horizontal tunnels are driven out to the seam; the material is brought up the shaft. It disturbs far less surface land, but it is expensive, slow, and hazardous — roof collapse, flooding, dust and gas — and it needs ventilation, pumping and support all the time the mine is open. |
| (c) Biological extraction | phytomining, bioleaching | Phytomining: plants are grown on low-grade ore or on old mine waste; they absorb metal compounds through their roots and concentrate them in their tissues; the plants are harvested and burned, and the metal is recovered from the ash. Bioleaching: bacteria are used on low-grade ore to produce a solution (a leachate) containing the metal compound, from which the metal is then obtained. Both work on ore too poor for ordinary mining, both use much less energy and disturb much less land — and both are slow. |
Choosing a method in one line
Shallow deposit → surface. Deep deposit → subsurface. Low-grade ore or old waste tips → biological. If a question describes a coal seam 400 m down, do not suggest opencast, however much you would like to write about it. And if a question says “the ore contains only 0.2 % copper”, that number is there to point you at bioleaching or phytomining.
1.2.3 The factors that decide whether to extract at all
A company does not dig a mine because the metal is there. It digs when eight separate things line up, and the syllabus names all eight. This is a favourite “suggest three factors…” question, and a favourite Paper 2 source-material question where you are given a report about a proposed mine and asked to decide.
| Factor | The question it answers | Why it can stop a mine |
|---|---|---|
| (a) Exploration | Is there anything there, and how sure are we? | Surveying, sampling and test drilling cost money before a single tonne is sold. If exploration cannot prove a large enough deposit, nothing goes ahead. |
| (b) Geology | What is the rock like around and above the deposit? | Hard rock is slow and expensive to cut; unstable or water-bearing rock means constant support and pumping; the depth and thickness of the seam decide which method is even possible. |
| (c) Accessibility and terrain | Can we get machinery in and ore out? | A deposit under a mountain, in dense forest, offshore or far from any road may need a new road, railway or port built first, and that cost is added to every tonne. |
| (d) Quantity and quality of deposit (ore grade) | How much is there and how rich is it? | Low grade means more rock moved, more energy used and more waste produced per tonne of metal. A small high-grade deposit and a huge low-grade one can be equally attractive; a small low-grade one is not. |
| (e) Climate | Can we work here, all year? | Extreme heat, deep cold, a long monsoon or seasonal flooding can shut a site for months, and workers must be housed and supplied through it. |
| (f) Environmental impact assessment | What will this do to the area, and will permission be given? | An EIA is a formal study, usually required by law before permission is granted. It can force a change of method, expensive mitigation, or refusal. |
| (g) Supply and demand | Does the world want this material? | Prices move. A metal in short supply and high demand justifies a difficult mine; if demand falls or a substitute appears, the same mine is abandoned. |
| (h) Cost and profit | Does the money work? | All the factors above end up here. Extraction, processing, transport, wages, restoration and taxes are set against the expected price. If the sums do not work, the deposit stays where it is. |
A shape for the eight factors
Group them into three: what is in the ground (exploration, geology, ore grade), what is on top of the ground (accessibility and terrain, climate, the EIA), and what is on the balance sheet (supply and demand, cost and profit). Three groups is much easier to recall under pressure than eight bullets, and if a question asks for “three factors” you can take one from each group and be certain they are genuinely different points.
1.2.4 Impacts — environmental, economic and social
Read the wording of this objective carefully: describe and explain the environmental, economic and social impacts. Explain means give the mechanism — the “because”. And notice that the syllabus asks for economic and social impacts as well as environmental ones, which means not all of the impacts are negative. Employment, local economies and infrastructure are on the list precisely because they are the other side of the argument. A candidate who lists only harms has answered a third of the question.
| Impact | Type | Describe and explain |
|---|---|---|
| (a) Loss of habitat and biodiversity | Environmental | Vegetation and soil are cleared over the whole working area, so the organisms living there lose food, shelter and breeding sites. Populations fall, and species that cannot move or that are found nowhere else may be lost from the area. Access roads also fragment what is left, cutting large habitats into small isolated pieces. |
| (b) Air, land, noise, visual and water pollution | Environmental | Air: dust from blasting, crushing and haul roads, plus exhaust gases from heavy machinery. Land: spoil heaps and tailings, which may contain toxic metals. Noise: blasting, drilling and lorries, day and night, affecting residents and wildlife. Visual: pits, tips and machinery in a landscape people value. Water: sediment washed into rivers, and acidic or metal-rich drainage from exposed rock and tailings entering surface water and groundwater. |
| (c) Water usage | Environmental / social | Mining uses very large volumes of water for washing, separating and dust suppression, and deep mines must be pumped continuously. This can lower the water table and reduce what is available to farms and households nearby, which matters most in exactly the dry regions where many mines are. |
| (d) Waste management | Environmental | Most of what is dug up is not the product. Overburden, waste rock and tailings must be stored somewhere, usually in tips or behind tailings dams. They occupy land, can be unstable, and can release sediment and dissolved metals for decades after the mine closes. |
| (e) Changes in employment opportunities | Economic / social | A mine creates jobs directly and in the businesses that supply it, often in areas with few alternatives, and wages are typically above local levels. But the jobs may go to incomers rather than local people, they may need skills the area does not have, and they end when the deposit does — and a town built on one mine has nothing to move to. |
| (f) Local and national economies | Economic | Wages are spent locally, supporting shops and services (the multiplier effect); the company pays taxes and royalties; exports earn foreign currency for the national economy. Against that, an economy that depends on one commodity is exposed when the world price falls, and profits from foreign-owned mines may leave the country. |
| (g) Facilities and infrastructure | Social / economic | Roads, railways, ports, power lines, water supply, housing, schools and clinics are often built for the mine and used by everyone. That is a real and lasting gain. The same influx can also overload existing services, push up local prices and rents, and leave infrastructure that has no purpose once the mine closes. |
Turning a description into an explanation
“Mining causes water pollution” is a description and scores one mark at most. “Mining causes water pollution because rainwater runs off the tailings, dissolving metal compounds, and carries them into the river, so that fish are poisoned and the water is unsafe to drink” contains the mechanism and the consequence, and that is where the second and third marks are. Train yourself to write because and so that in every explain answer.
1.2.5 Repairing the landscape afterwards
The syllabus splits management of damaged land into two ideas, and the difference between them is worth a mark on its own. Land restoration tries to return the land to something like its original condition. Repurposing accepts that the land has changed and gives it a new, useful job.
| (a) Land restoration | What is actually done |
|---|---|
| Replacement of overburden | The soil and rock stripped at the start is stored separately and put back at the end, in the right order, with the topsoil last. Storing the topsoil separately is the whole trick — mixed spoil is not soil and very little will grow in it. |
| Soil improvement | Adding organic matter, fertiliser and lime to restore nutrients, structure and pH, so that plants can establish on ground that has been compacted and stripped. |
| Bioremediation | Using living organisms — bacteria, fungi or plants — to break down or take up pollutants left in the soil and water, so that contamination is reduced without digging everything out and moving it elsewhere. |
| Tree planting | Trees stabilise the surface with their roots, reduce erosion and surface run-off, provide habitat, and screen the site visually. It is slow: a planted wood takes decades to resemble the one that was cleared. |
| (b) Repurposing land | What is actually done |
|---|---|
| Landfill | A worked-out pit is lined and used to bury waste, then capped and covered. It solves two problems at once — a hole and a waste stream — but requires a liner and long-term monitoring of leachate and methane. |
| Lakes | The pit is allowed or helped to flood. This can create a water supply, a fishery or a wetland habitat, but water in a mine void can be acidic or metal-rich and may need treating first. |
| Recreation | Sites become parks, sports pitches, climbing and watersports centres or visitor attractions, which brings income and jobs and keeps the land in public use. |
| Nature reserves | The disturbed ground is managed for wildlife. Bare rock, cliffs and shallow pools are habitats that are rare in an ordinary farmed landscape, so some quarries end up more biodiverse than the farmland around them. |
1.2.6 Discuss: benefits and limitations of these strategies
This is a “discuss” objective, so it is worth 4 to 8 marks and the mark scheme has two columns. Learn it as two columns.
| Benefits | Limitations |
|---|---|
| Land is returned to productive use — farming, forestry, housing or recreation — instead of being abandoned as derelict ground. | Restoration is expensive, and the cost falls at the end of a project when the deposit is exhausted and income has stopped. Companies may under-provide for it, or the operator may have gone. |
| Habitats and biodiversity can be re-established, and some repurposed sites (flooded pits, quarry faces) support species that the surrounding farmland does not. | A restored habitat is not the original one. Soil structure, seed banks and fungal networks take decades or centuries to rebuild, and species found nowhere else are not recovered by planting trees. |
| Erosion, dust and landslip are reduced once vegetation cover is re-established, protecting rivers downstream from silting. | Vegetation takes years to establish on compacted, nutrient-poor, sometimes contaminated ground, and may need repeated replanting and continued soil improvement. |
| Pollution is reduced: bioremediation can lower contamination in place, and capping and lining stop leachate reaching groundwater. | Bioremediation is slow and works only for certain pollutants; some metals cannot be broken down at all, only moved or locked up. Monitoring may be needed for decades. |
| Repurposing creates new jobs and income — recreation, tourism, waste management, fisheries — which partly replaces the employment lost when the mine closed. | The new jobs are usually fewer and lower paid than the mining jobs, so a mining town is rarely made whole by a country park. |
| Visual amenity improves, and local people regain access to land that was fenced off, which matters for health and for property values. | Landscapes cannot always be put back: a deep open pit or a large spoil heap changes the landform permanently, whatever is planted on it. |
The four-move evaluation
For every “discuss” question in this subject, make four moves: benefit → limitation → who bears the cost → over what timescale. Here: the benefit is land back in use; the limitation is that the ecosystem is not the same one; the cost is borne by the company if legislation forces it and by the taxpayer or the local community if it does not; and the timescale is that the profit is made in years while the recovery takes decades. That last sentence, on its own, is often the judgement mark.
Worked example
A company plans an open-pit copper mine on grazing land near a small town. Discuss the impacts of the mine on the local area. [6]
Read the command word first
Discuss, 6 marks. The mark scheme will have positive impacts and negative impacts, and will expect a conclusion. Aim for roughly three points each side, then one sentence of judgement. Do not spend all six lines on pollution.
Negative impacts — with mechanisms
Grazing land and its habitat are cleared for the pit and the spoil heaps, so biodiversity falls and farmers lose grazing. Dust from blasting and haul roads reduces air quality, and noise affects residents. Run-off from the tailings can carry metal compounds into the river, making water unsafe for people and livestock, and the mine's own water use may lower the water table.
Positive impacts — and these are half the marks
The mine creates direct employment and jobs in local suppliers, in an area where the alternative is grazing; wages are spent in the town, supporting shops and services. The company pays taxes and royalties, and copper exports earn foreign currency nationally. Roads, power and water built for the mine may improve services for the town as well.
The judgement
Say who gains, who loses, and for how long. The economic gains are real but temporary, ending when the deposit does, while habitat loss and contaminated ground can persist long afterwards; whether the mine is acceptable depends on how strongly restoration is enforced and whether local people rather than incomers get the jobs.
Three impacts each way, each with a because, then a one-sentence judgement that names the timescale.
Source BFigure 1.2A — land use on one mine site, before and after restoration
Objective 1.2.4 asks for the environmental impacts of extraction and 1.2.5 for the strategies that repair them. A land-use map is the usual way Paper 2 hands you both at once: the areas are printed on the blocks, so every figure you quote should come off the map rather than out of your memory.
Write every part out before you open the model answer. Reading a model answer you have not attempted teaches you almost nothing.
Source B — part (a)
Read Map 1 in Figure 1.2A. What area of the site is covered by waste rock and tailings?
The tailings block runs the full depth of the right-hand half of Map 1 and is printed as 130 ha. Always check the printed figure against the block you are looking at, because A, B and D are all real areas on the same map — they are simply the wrong blocks. Reading the key first and the numbers second is what stops this slip.
Source B — part (b)
Compare Map 1 with Map 2. What has replaced the open pit after restoration?
The 90 ha block in the same position on both maps changes from open pit to open water, so the pit has been allowed to flood. That is repurposing rather than restoration: the land is given a new use instead of being returned to what it was. The other three all happen on this site, but they happen on the waste and plant blocks, not on the pit.
- (c)Describe how the land use of the site changed between Map 1 and Map 2. Quote areas from the maps. [4]
- (d)Calculate the percentage of the 400 ha site that was bare industrial land in Map 1. Show your working. [2]
- (e)Explain why the 130 ha of waste rock and tailings has to be treated before grassland will grow on it. [3]
- (f)Discuss the benefits and limitations of repurposing the pit as a lake rather than filling it in. [6]
Model
Model answer — Figure 1.2A, parts (c) to (f)
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(c) The description, with figures
The 140 ha of woodland along the top of the site is unchanged in both maps. The 90 ha open pit has become 90 ha of open water. The 130 ha of waste rock and tailings has been reshaped into 60 ha of new woodland and 70 ha of grassland. The 40 ha of plant, roads and buildings has become 20 ha of recreation ground and 20 ha of retained roads and car park. Quote the pairs like that — a described change with a before and an after figure is worth more than a sentence saying the site “looks better”.
(d) The calculation
Bare industrial land in Map 1 is the pit plus the waste plus the plant: 90 + 130 + 40 = 260 ha. As a percentage of the whole site, 260 ÷ 400 × 100 = 65 %. Note what is not included: the 140 ha of woodland is inside the site boundary but is not bare, so counting it would give the wrong answer.
(e) The explanation
Tailings are crushed rock with no soil structure, almost no organic matter and very few nutrients, so roots have nothing to hold on to and nothing to feed on. They may also be acidic or contain metal compounds left from processing, so seedlings are poisoned. The strategy is the one named in 1.2.5(a): reshape the heaps, replace the overburden and the topsoil that was stored when the mine opened, improve the soil or use bioremediation, and only then seed.
(f) The discussion
Benefits. Flooding the pit is far cheaper than finding 90 ha worth of fill; the lake is a habitat and can be used for fishing, sailing or as a nature reserve; and it can store water for the surrounding area. Limitations. Water standing on freshly exposed rock can turn acidic and dissolve metals, so it may need monitoring and treatment for decades; a deep pit lake with steep sides is a drowning risk and has to be fenced; and the 90 ha is permanently lost to farming or building. Who bears the cost, and over what timescale. The company saves the cost of infill now; the local authority inherits the monitoring, the fencing and any treatment for as long as the lake exists. On balance a pit lake is a reasonable outcome where the rock is chemically stable and the community wants the recreation, and a poor one where the rock is sulfide-rich, because there the cheap option now is the expensive one later.
Checkpoint 1.2
Answer, then read the explanation even when you were right.
Your Score
0 / 18
Question 1
Which definition of an ore matches the syllabus wording?
B is the syllabus wording and it is only five words, so learn it as it stands. A describes a native metal such as gold, which is a special case, not the definition. C is the definition of a mineral, which is a component of an ore rather than the ore itself. D is overburden, which is what you take off to reach the ore.
Question 2
A coal seam lies 500 metres below the surface under farmland. Which extraction method is most suitable?
At 500 m the overburden is far too thick to strip, so a shaft is sunk and tunnels are driven to the seam. A and D are both surface methods and both would mean removing half a kilometre of rock and the farmland with it. B misapplies a real technique: bioleaching and phytomining recover metals from low-grade ore, and coal is not a metal.
Question 3
Which statement about phytomining is correct?
Phytomining grows plants on low-grade ore, lets them concentrate the metal in their tissues, then harvests and burns them so the metal can be recovered from the ash. A is bioleaching, the other biological method, and the two are easy to swap under pressure. C describes planting for stabilisation, which is land restoration, not extraction. D is smelting, a processing step that comes after extraction.
Question 4
A survey shows a large deposit of iron ore beneath dense forest, 200 km from the nearest road or railway. Which factor is most likely to stop the mine going ahead?
Two hundred kilometres of new road or railway through forest is a cost that must be paid before a single tonne is sold, and that is what accessibility and terrain means. B gets the factor the wrong way round: a large deposit is an argument for the mine, not against it. C contradicts the question, which says a survey has already been done. D is simply false about iron.
Question 5
What is the purpose of an environmental impact assessment before extraction begins?
The point of an EIA is that it happens first, so that the effects can be predicted and permission refused or conditions attached. A gets the timing wrong, which is exactly the error the word “assessment” invites. C is the cost and profit factor and B is part of exploration and geology; both are real factors in 1.2.3, but neither is what an EIA is for.
Question 6
Which impact of mining is best classified as economic rather than environmental?
Royalties and taxes are money flowing to a government, which is squarely economic and is a benefit rather than a harm. A and D are environmental impacts, on water and on land respectively. B is tempting because it affects farming, but the impact described is on the water table itself, so it is classified as environmental; the loss of income that follows would be the economic knock-on.
Question 7
Why is topsoil stored separately from the rest of the overburden during opencast mining?
Topsoil is the thin upper layer holding organic matter, nutrients, seeds and soil organisms; mix it with waste rock and you have spoil, not soil, and restoration fails. B invents a physical property — soil is lighter than rock, not heavier. C confuses the covering with the target. D describes soil improvement, which may be needed as well, but is not the reason for storing the topsoil apart.
Question 8
A worked-out quarry is flooded and managed as a wetland nature reserve. This is an example of
The quarry has not been put back as it was — it is now a lake — so this is repurposing rather than restoration, and that distinction is exactly what the question tests. B would require replacing the overburden and rebuilding the original land surface. A and C are both genuine restoration techniques, but neither describes turning a hole into a wetland.
Question 9
Which is a genuine limitation of restoring a mined landscape by planting trees?
Time is the honest limitation: the trees go in quickly but soil structure, seed banks and the associated species take decades or longer. B reverses a fact you will use again in 2.3 — roots bind soil and reduce erosion. C is false; screening is one of the reasons planting is done. D overstates a real difficulty into an impossibility, which is a common wrong-answer shape: compacted ground makes establishment harder, not impossible.
Question 10
A mining town closes its mine. Which statement best describes the economic effect on the town?
The multiplier works in reverse: wages stop, spending stops, and the shops and services that depended on that spending contract too. A confuses free time with money. C gets the direction of money wrong — restoration is a cost, and if the company has gone it is a cost to the public purse. D notices something true (less lorry damage) and calls it an improvement in infrastructure, which is a right-fact-wrong-conclusion answer.
Question 11
An open-pit mine clears 90 ha of forest. Which named impact describes what happens to the animals and plants that lived there?
The syllabus pairs habitat and biodiversity in one impact, so name both: the place is destroyed and the range of species living in it falls. B is a real impact of the same mine but it is about how the site looks to people, not about what lives there. C and D are the economic and social impacts, which belong in a different part of the same answer.
Question 12
The syllabus names five kinds of pollution from extraction. Which of these is the visual one?
Air, land, noise, visual and water are the five, and visual pollution is the one that damages the look of a landscape rather than its chemistry. A is noise, B is air and land, C is water. Learning the list of five as a list is worth doing, because a question that asks for three types will not accept three examples of the same type.
Question 13
Why does the syllabus list water usage at a mine as an impact separate from water pollution?
Usage is about quantity and pollution is about quality, and a mine can cause one without the other. Processing and dust suppression consume very large volumes, and in a dry region that water is taken from the same supply that irrigation and drinking water come from. C has it backwards: usage matters most where water is scarce.
Question 14
Tailings are stored behind a dam at a mine. Why does this waste need managing for decades after the mine closes?
Tailings are fine, wet and often chemically active, and the dam holding them has to be monitored and maintained long after the ore has gone. That is why waste management is its own named impact rather than a detail of land pollution. A and B are both comfortable answers that the existence of tailings dams disproves; D would cause exactly the failure described in C.
Question 15
Two deposits are the same size and depth. Deposit A is 2.4 % copper and deposit B is 0.4 % copper. What does that difference in ore grade mean?
Grade is the percentage of the useful metal in the rock, so a grade six times lower means six times as much rock must be dug, crushed and processed for the same tonne of copper. That is more fuel, more waste and more cost, which is why quantity and quality of deposit is one of the eight factors in the decision to extract at all.
Question 16
Why does a company carry out exploration and a geological survey before deciding to open a mine?
Exploration and geology are the first two of the eight factors because everything else depends on them: without the size, the depth and the grade there is no way to estimate cost, and no way to judge profit. A belongs to the environmental impact assessment stage, B to supply and demand, and D follows from the plan rather than shaping it.
1.3 Sustainable Management of Rocks, Ores and Minerals
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▶ Watch: finite resources and recycling
Opens on YouTube in a new tab. This is the weakest video set in Topic 1 and only four are worth your time. Most of what is online under “reduce, reuse, recycle” is about household plastic and food waste, not about rocks, ores and minerals, which is what 1.3 actually examines. Two further generic three-Rs clips were left out for that reason rather than listed to pad the panel. Nothing here covers 1.3.3(c) increased efficiency of extraction or 1.3.3(d) avoiding resource depletion.
Two definitions, both examinable word for word
Learn these exactly
A finite resource is a natural resource that is used up at a faster rate than it is replaced.
Sustainable management of resources is the use of strategies that ensure the needs of the present are met without compromising the ability of future generations to meet their own needs.
The second one is long, so break it into its two halves and learn them as a pair: meet the needs of the present … without compromising future generations. Both halves must be there. A candidate who writes only “using resources carefully so they last” has the idea but not the mark.
Look carefully at the definition of a finite resource, because it is not quite what most people assume. It does not say “a resource that will run out” or “a resource with a fixed amount”. It says it is used up faster than it is replaced. That is a statement about rates. Rocks, ores and minerals are being formed right now — the rock cycle never stopped — but at a rate of millimetres per thousand years, while we extract them by the billion tonnes per year. It is the mismatch between the two rates that makes them finite, and saying so is often the second mark.
That framing also explains why sustainable management is possible at all. If you cannot speed up the rate of replacement — and you cannot make new granite — then the only lever left is the rate of use. Every one of the seven strategies below is a way of pulling that lever.
1.3.3 The seven strategies
| Strategy | How it works | Where it runs into trouble |
|---|---|---|
| (a) Reduce and reuse | Use less material in the first place — thinner packaging, smaller components, designing products to last — and use items again in their existing form rather than treating them as waste. Reuse needs no reprocessing energy at all, which is why it sits above recycling. | Reducing consumption means persuading people and firms to buy less or design differently, which cuts against how most products are sold. Reuse depends on items being made repairable and on systems existing to collect and redistribute them. |
| (b) Recycling: accessibility, ease and education | Used material is collected, sorted, reprocessed and made into new products, so less ore is extracted. The three words the syllabus attaches are the conditions for it working: accessibility (collection points and kerbside collection close to people), ease (simple sorting, clear labelling, so it takes almost no effort), and education (people knowing what can be recycled and why it matters). | Recycling still costs energy and money, sorting mixed or contaminated material is difficult, and some products are made of materials bonded together that cannot be separated economically. Metals recycle very well and repeatedly; many composites do not. |
| (c) Increased efficiency of extraction | Better technology recovers more of the metal from the same rock, and makes previously uneconomic low-grade deposits worth working. Less ore has to be mined per tonne of metal produced, and less waste is created. | New equipment and processes are expensive to install, and higher efficiency can simply make extraction cheaper, encouraging more of it rather than less. |
| (d) Avoiding resource depletion | Deliberately controlling the rate of extraction so that a deposit is not exhausted — quotas on output, limits on licences, leaving some deposits unworked as reserves for the future. | It restricts income now for a benefit that arrives later, and a country that restricts its own output may simply lose the market to one that does not. |
| (e) Legislation | Laws that set the rules: mining licences and quotas, compulsory environmental impact assessments, required restoration bonds, recycling targets, bans on certain practices, taxes on raw material use. | A law is only as good as the political will behind it, laws stop at national borders, and industry may relocate to countries with weaker rules rather than comply. |
| (f) Enforcement | The machinery that makes legislation real: inspection, monitoring, licensing officers, fines and prosecution, and the power to close a site. The syllabus lists it separately from legislation precisely because the two are not the same thing. | Enforcement needs trained staff, equipment and money, over the whole life of every site. Illegal and informal mining is hard to police in remote areas, and fines that are smaller than the profit do not change behaviour. |
| (g) Use of alternative materials | Substituting a scarce material with a more abundant or renewable one — timber or bamboo instead of steel in some construction, aluminium or plastics instead of copper, glass fibre instead of metal cable, synthetic materials instead of scarce minerals. Demand for the finite resource falls. | The substitute may perform less well, cost more, or have its own environmental cost — plastics from petroleum, or timber from felled forest. Swapping one pressure for another is not automatically sustainable. |
Legislation and enforcement are two answers, not one
If a question asks for three strategies and you write “pass laws” and “make sure the laws are followed”, you get two marks, not one, because the syllabus lists them separately. This is quiet free marks. The same trick works with “reduce” and “reuse”, which are one lettered item but two distinct actions — though be careful, an examiner may treat those as one point, so make the third point come from a different letter.
1.3.4 Discuss: benefits and limitations of these strategies
| Benefits | Limitations |
|---|---|
| Deposits last longer, so the resource remains available to future generations — which is the definition of sustainable management being met. | Every strategy costs money now for a benefit that mostly arrives later, and governments and companies work to much shorter timescales than that. |
| Less extraction means less habitat loss, less waste rock, less pollution and less water use, so the environmental impacts in 1.2.4 are reduced at source. | Recycling, substitution and more efficient extraction all have their own energy demands, transport and emissions; the saving is real but smaller than it first appears. |
| Recycling metals uses far less energy than extracting them from ore, so it lowers both costs and emissions once the collection system exists. | Collection systems are expensive to build and depend on people using them, which requires sustained education and convenient access. |
| New industries and jobs are created in collection, sorting and reprocessing, some of them local and long-term. | Jobs may be lost in extraction, often in exactly the regions that have the fewest alternatives, so the gain and the loss fall on different people. |
| Legislation with real enforcement makes standards the same for every company, so a business that behaves well is not undercut by one that does not. | Enforcement is costly and uneven, rules stop at borders, and firms may move production to countries with weaker legislation, which moves the impact rather than removing it. |
| Reducing dependence on imported raw materials improves a country's security of supply and protects it from price shocks. | Countries whose economies depend on exporting minerals lose income if global demand falls, and they usually have least ability to absorb it. |
The judgement sentence that fits almost any of these
“These strategies extend the life of the resource, but the costs fall now and on the producer, while the benefits fall later and on everyone — which is why they generally require legislation and enforcement rather than goodwill.” That sentence names who bears the cost and over what timescale, which is what an evaluation mark is looking for.
Worked example
Explain why recycling aluminium is described as a sustainable management strategy. [4]
Step 1 — connect it to the definition
Aluminium ore is a finite resource: it is being used up far faster than geological processes replace it. Recycling reduces the rate of use, so the deposits last longer and are still available to future generations — which is precisely what the syllabus definition of sustainable management requires.
Step 2 — give the mechanism, because the command word is explain
Every tonne of aluminium recovered from used cans is a tonne of ore that does not have to be extracted, so less land is cleared, less overburden and waste rock is produced and less water is used. Reprocessing scrap aluminium also uses much less energy than extracting it from ore, so emissions from electricity generation fall as well.
Step 3 — add the condition, which is where the fourth mark often is
It only works if the material is actually collected: recycling depends on accessibility of collection points, ease of sorting, and education so that people know what to do. Without those, the strategy exists on paper only.
Reduces the rate of extraction of a finite resource; less land, waste and water per tonne; much lower energy use than extraction; but depends on accessibility, ease and education.
Applied question
A country recycles 12 % of its metal waste. It sets a target of 45 % within ten years. Suggest three actions the government could take, and one reason each might fail.
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This is a “suggest” question, which means you are applying the strategies to a situation rather than reciting them. Suggest questions accept any sensible answer that fits the context, so name the strategy and then say what it would look like in practice.
Action 1 — accessibility
Provide kerbside collection and local recycling centres so that recycling takes almost no extra effort. Why it might fail: collection vehicles, containers and depots are expensive, and rural and low-income areas are usually served last.
Action 2 — education
Run a schools and media campaign explaining what can be recycled and what happens to it. Why it might fail: knowing is not doing — campaigns raise awareness faster than they change habits, and the effect fades once the campaign stops.
Action 3 — legislation with enforcement
Set legal recycling targets for manufacturers, require products to be labelled and designed for separation, and inspect and fine those who do not comply. Why it might fail: enforcement needs inspectors and money over many years, and if fines are lower than the cost of compliance, firms will simply pay them.
The judgement
The three work together rather than separately: legislation without accessibility asks people to do something inconvenient, and accessibility without education means the wrong things go in the bin and whole loads are contaminated and rejected.
Source CFigure 1.3A — copper: ore grade, waste and recycling, 1980 to 2024
A data table is a source in exactly the same way a graph is, and the same rules apply: read the units in the header before you read a number, and quote figures when you describe a trend. This table is the evidence behind 1.3.1 (why a resource is finite in practice) and 1.3.3 (why recycling and efficiency of extraction are strategies rather than slogans).
| Year | Average ore grade mined (% copper) | Waste rock per tonne of copper (tonnes) | Energy per tonne of copper (GJ) | Share of copper supply from recycling (%) |
|---|---|---|---|---|
| 1980 | 1.60 | 62 | 40 | 22 |
| 1995 | 1.10 | 90 | 52 | 26 |
| 2010 | 0.80 | 124 | 68 | 30 |
| 2024 | 0.55 | 181 | 95 | 34 |
Figures are for one large copper-producing country. The waste column assumes all of the copper in the ore is recovered, so it is 100 ÷ grade, minus the one tonne of copper itself.
Write every part out before you open the model answer. Reading a model answer you have not attempted teaches you almost nothing.
Source C — part (a)
Read the table in Figure 1.3A. How much waste rock was produced per tonne of copper in 2024?
Find the 2024 row, then the waste column: 181 tonnes. The check that proves you are in the right cell is the trend — waste per tonne of copper rises down the column as the grade falls, so the last row must hold the largest number. A and D are the other numbers on the same row, which is the commonest way to lose an easy mark.
Source C — part (b)
By how many percentage points did the recycled share of copper supply rise between 1980 and 2024?
Subtract, do not just copy: 34 minus 22 is 12. Percentage points are what you get when you subtract one percentage from another, and they are not the same as a percentage change — as a percentage change this rise is 12 divided by 22, which is about 55 %. That is why C is on the list, and why the units in the question matter.
- (c)Describe the trend in average ore grade between 1980 and 2024. Quote figures. [3]
- (d)Calculate the percentage fall in average ore grade between 1980 and 2024. Show your working. [2]
- (e)Explain, using the table, why a falling ore grade makes recycling more attractive. [4]
- (f)Discuss the benefits and limitations of relying on recycling to meet a rising demand for copper. [6]
Model
Model answer — Figure 1.3A, parts (c) to (f)
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(c) The trend, with figures
The average grade fell steadily throughout, from 1.60 % in 1980 to 1.10 % in 1995, 0.80 % in 2010 and 0.55 % in 2024. There is no year in which it rose. A describe-the-trend answer needs the direction, the start value and the end value at minimum; adding that the fall is continuous rather than sudden is what lifts it.
(d) The calculation
Fall = 1.60 − 0.55 = 1.05 percentage points. As a percentage of the starting value, 1.05 ÷ 1.60 × 100 = 65.6 % (65.625, so 65.6 % to one decimal place, or about 66 %). Always divide by the starting value in a percentage change question — dividing by the finishing value is the single commonest arithmetic error on this kind of part.
(e) The explanation
As the grade falls, more rock has to be moved for each tonne of metal: waste rock per tonne of copper rises from 62 t to 181 t, roughly a threefold increase, because a tonne of copper now sits inside about 180 tonnes of ore instead of 62. Moving, crushing and processing all of that takes energy, and the energy column rises from 40 GJ to 95 GJ per tonne, about 2.4 times. Recycled copper skips the digging, the crushing and most of the separation entirely, so the gap between the cost of new copper and the cost of recycled copper widens every year the grade falls — which is why the recycled share in the last column climbs from 22 % to 34 % over the same period.
(f) The discussion
Benefits. Recycling uses far less energy per tonne than mining low-grade ore; it produces no overburden, no tailings and no new hole in the ground; copper does not degrade when it is melted, so it can be recycled repeatedly; and it reduces a country’s dependence on imported ore. Limitations. The table itself sets the ceiling — recycling supplies 34 % and not more, because you can only recycle copper that was mined in the past and has reached the end of its life, and much of it is still in use in buildings and cables that will not be scrapped for decades. Collection depends on accessibility, ease and education; scrap that is mixed with other metals has to be separated, which costs energy and money; and if demand is rising faster than old copper comes back, recycling can never close the gap on its own. Judgement. Recycling is the strategy with the best return per unit of effort and it should be pushed hard, but it extends the life of the resource rather than replacing extraction, so it belongs alongside reduce and reuse, improved efficiency of extraction and the use of alternative materials, not instead of them.
Checkpoint 1.3
Answer, then read the explanation even when you were right.
Your Score
0 / 11
Question 1
Which definition of a finite resource matches the syllabus wording?
The syllabus definition is about rates: used up faster than replaced. A is the version most people assume and it is subtly wrong — rock is still being made, just far too slowly to matter. C describes scarcity of location, not finiteness. B describes a market consequence of scarcity rather than the resource itself.
Question 2
Which phrase must appear in a full definition of sustainable management of resources?
The definition has two halves and this is the second one; the first is “meeting the needs of the present”. A misses that first half entirely — sustainability is not about using nothing. B invents a deadline the definition does not contain. D confuses sustainability with an argument about who profits, which is a different debate.
Question 3
Why does the syllabus list reuse ahead of recycling as a strategy?
Recycling melts, cleans and remakes material, all of which needs energy and transport; reuse skips every one of those steps. A confuses quality with the point being made. C is false — glass, paper and many plastics are recycled routinely. D reverses reality, since recycling targets are the thing that legislation more commonly requires.
Question 4
A government sets a legal recycling target but does not fund inspections or fines. Which strategy is missing?
Legislation and enforcement are separate items in the syllabus for exactly this reason: an unenforced law changes nothing. B is ruled out by the question, which says a legal target was set. A and D are real strategies but neither is what is missing here — the gap described is inspection and penalty.
Question 5
New technology allows a company to recover 90 % rather than 60 % of the copper in its ore. Which strategy is this?
More metal out of the same rock is efficiency of extraction, and its benefit is that less ore must be mined per tonne produced. C would mean using something other than copper. B would mean mining less on purpose, which is not what better technology does. D is tempting because both mean “less waste”, but recycling starts with a used product, not with ore.
Question 6
Which is a genuine limitation of replacing a scarce metal with a synthetic alternative?
Substitution moves the pressure rather than removing it — a plastic made from petroleum draws on a different finite resource and carries its own emissions and waste. B invents a rule. C reverses the mechanism: substitution reduces demand for the metal. A overstates a real point; substitutes often perform less well, but “no material for any purpose” is plainly too strong.
Question 7
Which is the strongest argument against a country limiting its own mineral exports to conserve reserves?
This is the real trade-off: the cost is immediate and local, the benefit is distant and shared, and a country that restricts supply may simply hand the market to a competitor. B contradicts the strategy's own mechanism. C is false for rocks and ores on any human timescale. D asserts a link between export limits and pollution that does not follow.
Question 8
Which statement best explains why rocks and ores are treated as finite even though the rock cycle continues?
Finiteness is a comparison of two rates, and that is what B states. A is simply untrue; the cycle is running now. C is false, and new deposits are still found. D confuses extraction with destruction — the metal still exists after use, which is exactly why recycling is possible.
Question 9
The syllabus names three things that decide whether recycling actually works in practice. Which set is it?
Accessibility means the bins and collections are within reach, ease means separating waste takes almost no effort, and education means people know what goes where and why. All three are needed: a scheme that is legal and well publicised but inconvenient still fails. B, C and D are all real strategies from 1.3.3, but they are listed separately from recycling.
1.4 Energy Resources
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▶ Watch: fossil fuels, renewables and generation
Opens on YouTube in a new tab. The first three are badged IGCSE 0680 and follow the old chapter numbering; the rest are general science, taken one resource at a time. Between them they cover fossil fuel formation, hydro, geothermal and nuclear, but there is no clip here on tidal, wave or biofuel generation, and none of them works through 1.4.5, the factors affecting demand.
1.4.1 Where fossil fuels came from — the second ordered chain
All three fossil fuels start the same way and diverge at one step: what died, and where. Coal comes from land plants; petroleum and natural gas come from marine organisms. After that the story is the same — burial, heat, pressure, time. Because it is a chain, it is marked as a chain, so learn the steps in order.
Formation of coal, petroleum and natural gas. The named steps are: dead organisms → buried without oxygen → compressed by overlying layers over millions of years → heat and pressure convert the remains to fuel.
| Fuel | The chain, in order |
|---|---|
| (a) Coal | Dead land plants (trees, ferns) fall into swamp water → the water has little oxygen, so decomposers cannot break them down fully → the partly decayed plant material builds up as peat → it is buried under sediment → over millions of years the weight of the layers above compresses it and raises the temperature → water and gases are driven out, the carbon content rises, and coal is formed in seams. |
| (b) Petroleum (oil) | Dead marine organisms — plankton and other tiny sea life — sink to the sea floor → they are buried in mud in the absence of oxygen, so they do not decay completely → more sediment buries them deeper → over millions of years high pressure and high temperature convert the remains to liquid petroleum → being less dense than water it moves upwards through permeable rock until it is trapped beneath a layer of impermeable rock. |
| (c) Natural gas (methane) | Formed by the same process from the same marine organisms, but at greater depth, where temperatures are higher. The organic material is converted to gas rather than liquid. Being the least dense, the gas collects above the oil, held under the same impermeable cap rock — which is why drilling for one often finds the other. |
The four words that carry the marks
Dead. Buried. Airless. Squeezed. Every fossil-fuel formation answer needs: named dead organisms, burial under sediment, absence of oxygen so decomposition is incomplete, and heat and pressure over millions of years. The most commonly dropped mark is the anaerobic one — if oxygen had been present, decomposers would have broken the material down completely and there would be no fuel.
Coal is plants; oil and gas are sea life
“Oil is made from dead dinosaurs” is the popular version and it will not earn a mark. Say marine organisms or plankton. And for coal, say land plants in a swamp, not “trees underground”.
1.4.2 Classifying energy resources
Renewable (the syllabus also calls them non-finite) means the resource is replaced as fast as it is used, or is effectively inexhaustible. Non-renewable (finite) means it is used faster than it is replaced — the same definition you learned in 1.3.1.
| (a) Renewable / non-finite | (b) Non-renewable / finite |
|---|---|
|
Biofuels: bioethanol, biomass, biogas and wood Geothermal power Hydro-electric power Tidal power Wave power Solar power Wind power |
Fossil fuels: coal, petroleum (oil) and natural gas Nuclear power using uranium |
Nuclear is not renewable
Nuclear power produces almost no carbon dioxide during generation, which makes people want to file it with the renewables. The syllabus is explicit: nuclear power using uranium is non-renewable, because uranium is a mined finite ore. Low-carbon and renewable are two different claims — keep them apart and you will not lose the mark.
The other classification trap is biofuels. Wood, biomass, biogas and bioethanol are renewable, because the plants they come from can be regrown within a human timescale. They still release carbon dioxide when burned. Renewable does not mean clean.
1.4.3 How each resource actually generates electricity
Almost all of these end in the same place: something spins a turbine, the turbine turns a generator, and the generator produces electricity. Learn that sentence once and then all you have to remember for each resource is what spins the turbine. Solar photovoltaic cells are the one genuine exception — they produce electricity directly, with no turbine at all.
| Resource | What turns the turbine (or what happens instead) |
|---|---|
| Coal, oil, natural gas | The fuel is burned in a power station; the heat released boils water to make high-pressure steam; the steam drives a turbine which turns a generator. Gas can also be burned to drive a gas turbine directly. |
| Nuclear (uranium) | Uranium nuclei undergo fission in a reactor, releasing heat; the heat boils water to steam; steam drives a turbine and generator. Same ending as coal — only the source of the heat differs, and no fuel is burned. |
| Biomass, wood, biogas, bioethanol | Burned to release heat, which boils water to steam and drives a turbine and generator, exactly as coal does. Biogas is produced by anaerobic digestion of organic waste first; bioethanol is made by fermentation of crops and is mostly used as a vehicle fuel rather than for electricity. |
| Geothermal power | Water is pumped down into hot rock deep underground, or hot water and steam are taken from a natural reservoir; the steam returns to the surface and drives a turbine and generator. It needs a region where hot rock is close enough to the surface. |
| Hydro-electric power | A dam holds water in a reservoir at height; water is released through pipes and its movement drives a turbine and generator. The higher the drop and the greater the flow, the more electricity is produced. |
| Tidal power | A barrage is built across an estuary; the rising and falling tide forces water through turbines set into the barrage, turning generators. Output is intermittent but entirely predictable, because tides are. |
| Wave power | Floating or shoreline devices are moved up and down by passing waves; that movement drives a turbine or generator, either directly or by forcing air or fluid through it. |
| Solar power | Two routes. Photovoltaic cells convert light energy directly into electricity, with no moving parts and no turbine. Concentrated solar uses mirrors to focus sunlight onto a fluid, heating it to make steam that drives a turbine and generator. |
| Wind power | Moving air turns the blades of a turbine, which turns a generator. Turbines are grouped into wind farms, on land or offshore where wind speeds are higher and steadier. |
One sentence covers eight of the nine
“Heat or movement turns a turbine, the turbine turns a generator, the generator makes electricity.” Coal, gas, oil, nuclear, biomass and geothermal all get there by making steam. Hydro, tidal, wave and wind get there by moving something directly. Only photovoltaic solar skips the turbine entirely. If you can sort a resource into those three groups you can describe its generation without memorising nine separate paragraphs.
1.4.4 Discuss: benefits and limitations of each energy resource
This is the largest “discuss” objective in Topic 1 and it is where the extended-response marks live. The table below gives both sides for every resource named in 1.4.2. Read down the limitations column for the renewables and notice that they are real: an answer that treats renewables as free of problems is as unbalanced as one that treats fossil fuels as having no advantages, and both cap out at the same middling mark.
| Resource | Benefits | Limitations |
|---|---|---|
| Coal | Large reserves in many countries; cheap per unit of energy; reliable output that can be run continuously; existing power stations, transport and skilled workforce already in place; supports large employment. | Finite. Burning releases carbon dioxide (a greenhouse gas) and sulfur dioxide (which contributes to acid rain), plus particulates that affect health. Mining causes the land, water and habitat impacts of 1.2.4. Ash must be disposed of. |
| Petroleum (oil) | Very high energy content per kilogram; easy to transport and store as a liquid; essential for vehicles and aircraft where alternatives are limited; the raw material for plastics, fertilisers and medicines. | Finite. Releases carbon dioxide when burned. Extraction and shipping risk spills that affect coasts and marine life. Prices are volatile and supply is concentrated in a few regions, which creates political and economic risk. |
| Natural gas | Cleanest of the three fossil fuels — roughly half the carbon dioxide of coal per unit of electricity, and very little sulfur dioxide or particulate matter. Gas power stations are quick to build and can be turned up or down rapidly to match demand. | Finite, and still a source of carbon dioxide. Methane leaking from wells and pipelines is itself a powerful greenhouse gas. Needs pipelines or liquefaction for transport, so supply can be disrupted, and prices move sharply. |
| Nuclear (uranium) | Very large energy output from a very small mass of fuel; almost no carbon dioxide, sulfur dioxide or particulates during generation; reliable continuous output regardless of weather; a small quantity of uranium lasts a long time. | Uranium is finite and mined, with all the impacts of mining. Radioactive waste stays hazardous for thousands of years and must be stored securely. Power stations are extremely expensive to build and to decommission. Accidents are rare but their consequences are severe and long-lasting, and public acceptance is often low. |
| Biofuels (bioethanol, biomass, biogas, wood) | Renewable, since crops and trees can be regrown. Biogas turns waste that would otherwise be a disposal problem into fuel, and leaves a digestate that can be used as fertiliser. Bioethanol can be blended into petrol using existing engines. Locally produced, so it reduces dependence on imports and supports rural incomes. | Burning releases carbon dioxide, and wood also releases particulates. Growing fuel crops uses land, water and fertiliser that could grow food — the food-versus-fuel problem you meet again in 2.2.4. Energy content per kilogram is lower than fossil fuels. If forests are cut faster than they regrow, wood stops being renewable in practice. |
| Geothermal | Continuous output day and night, independent of weather, so it is one of the few renewables that is genuinely reliable. Very low emissions in operation. A small surface footprint. Running costs are low once built. | Only viable where hot rock lies near the surface, which is a small number of regions. High drilling and construction costs. A site can cool over decades if heat is taken faster than it is replaced, and drilling can release dissolved gases and, in some settings, trigger small earth tremors. |
| Hydro-electric | Large, reliable output with no fuel cost and no emissions during generation. Output can be increased within seconds to meet peak demand. The reservoir can also supply drinking water, irrigation, flood control, fisheries and recreation. Very long working life. | Building a dam floods a large valley, destroying habitats and farmland and displacing people, sometimes in very large numbers. It traps silt, so land downstream loses the sediment that fertilised it and the reservoir gradually fills. It blocks fish migration, changes river flow, and there is a small but serious risk of dam failure. Very high construction cost, and it needs the right river and valley. |
| Tidal | Entirely predictable years in advance, unlike wind or sun, so output can be planned for. No fuel cost, no emissions in operation, high output from a single barrage, and a very long working life. The barrage may also serve as a road crossing and offer flood protection. | Very high construction cost, and only a limited number of estuaries have a large enough tidal range. A barrage alters the estuary it is built in, affecting the mudflats that feeding birds and other estuary organisms depend on, and it obstructs shipping and fish movement. Output stops between tides, so other sources are still needed. |
| Wave | No fuel cost and no emissions in operation. Uses no land. Many countries have long coastlines, so the potential resource is widely distributed, and waves continue at night unlike solar. | Output varies with the weather and is unreliable. Devices must survive storms and salt water, so maintenance costs are high and the technology is much less developed than wind or solar. Installations can interfere with fishing and shipping and alter the shoreline habitat. |
| Solar | No fuel cost, no emissions in operation, and no moving parts in photovoltaic panels so maintenance is low. Panels can be fitted to existing roofs, using no extra land, and can supply remote settlements with no grid connection at all. Output is highest at midday, which in hot countries matches peak demand for cooling. | No output at night and much less on cloudy days, so storage or a back-up supply is needed. Output is poor at high latitudes and in cloudy climates. Large solar farms need land. Manufacturing panels uses energy and mined materials, and panels have to be disposed of or recycled at the end of their life. |
| Wind | No fuel cost and no emissions during generation. Turbines are relatively quick to build and can be added one at a time. Land between turbines can still be farmed. Offshore wind is stronger and steadier, and a single modern turbine supplies a large number of homes. | Output is intermittent and depends on wind speed, so it cannot be relied on to meet demand at a given moment. Turbines are visually intrusive and produce noise, which causes local objection. They can kill birds and bats. Offshore construction and maintenance are expensive, and the best wind sites are often far from the cities that need the electricity. |
The four words that separate the renewables in an exam answer
Reliable, predictable, intermittent, continuous. These are not the same thing and examiners reward the distinction. Wind and solar are intermittent and hard to predict. Tidal is intermittent but completely predictable. Geothermal, hydro-electric and biomass are continuous and can be run on demand. If you are asked why a country cannot run entirely on wind and solar, the answer is not that they are weak — it is that supply does not match demand in time, which is why 1.5.1 lists battery storage as a strategy.
1.4.5 What makes demand for energy rise
The command word here is describe and explain, so each factor needs its mechanism. Notice that the last three factors on the list are not about demand going up at all — they are about supply going wrong, and about how that changes what people demand and how much they pay.
| Factor | Explanation — the mechanism |
|---|---|
| (a) Transport | As countries develop, more people own vehicles and travel further and more often, and freight moves greater distances; air travel grows fastest of all. Almost all of that runs on fuel, so energy demand rises directly with the number of journeys. |
| (b) Personal and national wealth | Richer households buy more appliances — refrigerators, air conditioning, televisions, computers, cars — and use them more. Richer countries build more infrastructure and can afford to import more fuel. Wealth is the strongest single predictor of energy use per person. |
| (c) Climate | Cold regions use large amounts of energy for heating; hot regions use large amounts for air conditioning and refrigeration. Extremes in either direction raise demand, and demand also swings with the seasons, which is why a grid must be built for its peak rather than its average. |
| (d) Human population size | More people need more lighting, cooking, heating, water treatment, transport, food production and manufactured goods. Total demand rises with population even if demand per person stays exactly the same — and in most growing populations it is rising too. |
| (e) Industry | Manufacturing, mining, smelting, cement and chemicals are very energy-intensive. A country that industrialises sees demand rise sharply, and heavy industry can account for a large share of a national total on its own. |
| (f) Disruption to supply | War, political disputes, strikes, accidents, damaged pipelines or extreme weather can cut supply suddenly. Prices rise, users switch to whatever else is available, and governments respond by building reserves and diversifying sources — which changes the pattern of demand between resources. |
| (g) Unreliable supply | Where power cuts are frequent, households and businesses buy diesel generators and batteries and run them as back-up. That raises total energy demand, and usually shifts it onto more expensive and more polluting sources. |
| (h) Scarcity of resources | As a resource becomes scarce its price rises. Users reduce consumption or switch to alternatives, so demand for the scarce resource falls while demand for the substitute rises. Scarcity therefore changes the mix of resources demanded, not just the total. |
Worked example
A country's electricity demand rose by 60 % in twenty years while its population rose by only 15 %. Suggest and explain three reasons for the difference. [6]
Read what the numbers are telling you
Demand per person has gone up, not just the number of people. So the marks are in the factors other than population. Notice that the question has already given you population as the thing that does not explain it — writing about population size would waste a point.
Reason 1 — rising wealth
Incomes have risen, so households own more appliances, particularly refrigerators and air conditioning, and use them for longer. Energy use per person therefore rises faster than the number of people.
Reason 2 — industrialisation
New manufacturing, cement and metal industries are highly energy-intensive, so a small number of new factories can add a large amount of demand without any change in the population at all.
Reason 3 — transport, or climate
More vehicles on the roads, and a shift to electrically propelled vehicles, moves transport demand onto the electricity grid. Alternatively: a hot climate combined with rising wealth means air conditioning spreads from a few buildings to most of them, which raises electricity demand steeply and unevenly across the year.
Three factors, each with a because, and none of them population. Two marks each: the factor, and the mechanism that links it to demand per person.
Source DFigure 1.4A — electricity generation mix of four countries, 2024
A stacked bar is the standard way Paper 2 presents an energy mix, and it rewards a candidate who can add two segments together in her head. Read the key first: the classification into renewable and non-renewable (1.4.2) is what most of the marks turn on, not the arithmetic.
Write every part out before you open the model answer. Reading a model answer you have not attempted teaches you almost nothing.
Source D — part (a)
Read Figure 1.4A. Which country generates the largest percentage of its electricity from fossil fuels?
Fossil fuels on this chart means coal plus natural gas, so add the bottom two segments of each bar: P gives 62 + 18 = 80, which beats S on 22 + 40 = 62. C is the trap: 68 % is a big number in a single segment, but nuclear is non-renewable and is not a fossil fuel, because uranium is mined as an ore rather than formed from buried organisms.
Source D — part (b)
What percentage of Country Q’s electricity comes from renewable (non-finite) resources?
Renewable on the 0680 list means hydro-electric, wind and solar here, so 38 + 20 = 58. A and D each count only one of the two renewable segments. C counts nuclear and gas as renewable, which is the single most expensive classification error in this sub-topic: nuclear is finite because the uranium runs out.
- (c)Compare the electricity mix of Country P with that of Country R. [4]
- (d)Calculate the percentage of Country S’s electricity that is generated from finite resources. Show your working. [2]
- (e)Explain how the hydro-electric power in Country Q’s mix is used to generate electricity. [3]
- (f)Suggest which of the four countries is most exposed to a disruption to its energy supply, and justify your choice. [4]
Model
Model answer — Figure 1.4A, parts (c) to (f)
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(c) The comparison
Compare means both, side by side, with the similarity and the differences — not two separate descriptions. Country P generates 80 % of its electricity from fossil fuels (62 % coal, 18 % gas) whereas Country R generates only 8 %, all of it gas. Country R relies on nuclear for 68 % while Country P uses nuclear for only 3 %. Their renewable shares are closer but still differ: R has 12 % hydro and 12 % wind and solar, a total of 24 %, against P’s 10 % and 7 %, a total of 17 %. The similarity worth stating is that both depend mainly on finite resources — 83 % for P and 76 % for R — they simply choose different ones.
(d) The calculation
Finite means fossil fuels plus nuclear. For Country S that is coal 22 + natural gas 40 + nuclear 0 = 62 %. Check it against the other half of the bar: hydro 6 + wind and solar 32 = 38, and 62 + 38 = 100, so the reading is consistent.
(e) The explanation
Water is held behind a dam in a reservoir, so it has stored energy because of its height. When it is released it falls through pipes and its moving mass turns a turbine, and the spinning turbine drives a generator, which produces the electricity. Say the turbine sentence explicitly: almost every resource on the 0680 list ends that way, which is why the exception — solar photovoltaic, where the cell converts light directly — is the one they like to ask about.
(f) The suggestion, justified
Country P. It draws 80 % of its electricity from coal and gas, both of which have to be dug up or piped in continuously, so a strike, a price shock or a pipeline closure hits four fifths of its generation, and it has only 17 % renewable capacity to fall back on. Two honest qualifications, and stating them is what earns the fourth mark. First, the figure does not tell us whether P mines its own coal — a country burning coal from its own mines is far less exposed than one importing it, so the answer depends on information the source does not give. Second, Country Q is not risk-free either: 38 % of its electricity is hydro, and hydro depends on rainfall, so a drought is its equivalent of a supply disruption.
Checkpoint 1.4
Answer, then read the explanation even when you were right.
Your Score
0 / 15
Question 1
Which organisms formed the material that became coal?
Coal is land plants; oil and gas are marine organisms. A describes the origin of petroleum and natural gas, and swapping the two is the single commonest error in this objective. C is the “dead dinosaurs” story, which earns nothing. D is invented, though deep bacteria do exist.
Question 2
Why must the dead organisms be buried in conditions without oxygen for a fossil fuel to form?
The anaerobic condition is what stops decomposition finishing, so the carbon-rich material survives to be buried and compressed. This is the most frequently dropped mark in the objective. A and D invent chemistry that does not happen. B reverses the role of oxygen entirely — it is not stored for a later step.
Question 3
Which energy resource is classified as non-renewable by the syllabus?
Uranium is a mined ore, so nuclear sits with the fossil fuels as finite, however low its emissions are during generation. This is the classification trap of the whole sub-topic: low-carbon and renewable are different claims. A and C are biofuels and B is geothermal, and all three appear in the renewable list.
Question 4
Which energy resource generates electricity without using a turbine?
Photovoltaic cells convert light energy straight into electricity with no moving parts, and that is the one genuine exception in the whole list. B, C and D all end in a spinning turbine driving a generator; geothermal and nuclear reach it by making steam, tidal by moving water through it. Note that concentrated solar, which uses mirrors to make steam, does use a turbine.
Question 5
Which is a genuine limitation of hydro-electric power?
Flooding a valley is the central limitation: habitat and farmland are lost, people are moved, and silt is trapped behind the dam. C states the opposite of one of its main benefits, since a hydro station can go from nothing to full output in seconds. B belongs to coal. D is wrong twice over — there is no fuel and no fuel price.
Question 6
Why is tidal power described as predictable when wind power is not?
Predictable and continuous are not the same word. Tides are driven by the Moon and Sun, so their timing is known years ahead, but output still stops between tides — which is why B is wrong. C overstates it, since storms do affect an estuary. A describes battery storage, which is a separate strategy from 1.5.1 and is not part of a barrage.
Question 7
Which statement about biofuels is correct?
Renewable describes the rate of replacement, not the emissions: crops regrow in a season, and burning them still produces carbon dioxide. A confuses a growing season with geological time. C is the “renewable means clean” assumption that costs marks throughout this topic. D is false — bioethanol is made from sugar cane and maize grown for the purpose.
Question 8
A country with frequent power cuts sees a rise in sales of diesel generators. Which factor affecting energy demand does this illustrate?
Unreliable supply is listed as a separate factor precisely because it raises demand: people buy back-up equipment and run it, usually on a more expensive and more polluting fuel. B picks up a true fact about diesel that does not explain the behaviour. C and D each name a real factor but neither is the cause described in the question.
Question 9
Which is the strongest reason a government might build a gas-fired power station rather than a coal-fired one?
Gas is the cleanest of the three fossil fuels, at roughly half the carbon dioxide of coal per unit of electricity and with very little sulfur dioxide, and gas stations are also quicker to build and to adjust. A is false: gas is a fossil fuel and finite. B is false, since gas turbines are turbines. D ignores the extraction impacts you met in 1.2.4 and meet again in 1.6.
Question 10
Which pair of factors best explains why energy demand per person is much higher in wealthy countries?
Demand per person is driven by what each person owns and does, so wealth and transport are the pair that fit. C leads with population, which raises the total but not the figure per person. A names two factors that change the mix and price of supply rather than the level of consumption. D pairs a real factor with one that would push demand the other way.
Question 11
Which of these energy resources does NOT generate electricity by turning a turbine?
Almost every resource on the 0680 list ends the same way, with something spinning a turbine that drives a generator — water, steam, wind or tide. Solar photovoltaic is the exception: the cell converts light straight into electricity. Learn the exception and you can answer the whole objective from one sentence about steam or moving water.
Question 12
How did petroleum and natural gas form?
Oil and gas come from plankton and other tiny marine organisms that sank into the mud of a sea bed, were buried, and were cooked slowly by heat and pressure without oxygen. A is the coal route, which starts with land plants in a swamp, and mixing the two up is the commonest error in 1.4.1. C and D describe processes that make neither fuel.
Question 13
A country’s population and its winters are both unchanged, but its demand for electricity has doubled in twenty years. Which factor best explains that?
The question has already ruled out two of the eight factors for you, which is a favourite Cambridge move: read what has been excluded before you choose. With climate and population held fixed, personal and national wealth is what is left — richer households buy appliances, air conditioning and cars, and industry grows alongside them. D reverses the relationship, because scarcity restricts supply.
1.5 Conservation and Management of Energy Resources
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▶ Watch: heat pumps, hydrogen and battery storage
Opens on YouTube in a new tab. Not one of these is an 0680 lesson — they are general explainers, and they only cover 1.5.2 (heat pumps and hydrogen) and 1.5.1(g) battery storage. There is nothing here on insulation, on energy-efficient devices and electrically propelled vehicles, or on transport policies, which are three of the eight strategies in 1.5.1. Those you learn from the table on this page and from Source E below.
1.5.1 Eight strategies for managing energy resources
The strategies split neatly into two halves and it is worth seeing that before you learn the list. Items (a) to (f) are about using less of what we already have. Items (g) and (h) are about getting more out of what we have, and finding new sources. If a question asks for “two contrasting strategies”, take one from each half.
| Strategy | How it works | Limitation |
|---|---|---|
| (a) Reducing consumption | Simply using less: switching off lights and appliances, lowering heating and raising air-conditioning settings, shorter journeys, less standby power. Costs nothing to start and takes effect immediately. | Depends on millions of individual decisions repeated every day. Behaviour tends to drift back, and there is a floor below which comfort, health and business activity are affected. |
| (b) Insulation | Loft, wall and pipe insulation, double glazing and draught-proofing slow the transfer of heat out of a building in winter and into it in summer, so far less energy is needed to keep the temperature comfortable. | Costs money up front, and the people in the worst-insulated housing are often those least able to pay. It is difficult and expensive to retrofit into old buildings. |
| (c) Energy-efficient devices, including vehicles and electrically propelled vehicles | Appliances, lighting and machinery that deliver the same service for less energy — LED lamps in place of filament bulbs, efficiency-rated appliances, more efficient engines. Electrically propelled vehicles convert a much larger share of their energy into motion than a petrol engine does, and produce no exhaust emissions where they are driven. | New equipment costs more to buy, and manufacturing it uses energy and materials. An electric vehicle is only as clean as the electricity charging it, and its battery needs mined lithium, cobalt and other minerals — which takes you straight back to 1.2.4. |
| (d) Exploiting existing energy resources | Getting more from resources we already have rather than finding new ones: reworking older oil and gas fields with better technology, upgrading power stations to higher efficiency, reducing losses in transmission, and using waste heat from power stations to heat buildings. | Extending the life of fossil-fuel infrastructure keeps emissions going and can delay the switch to alternatives. Older fields become progressively more expensive and more difficult to work. |
| (e) Education on energy conservation | Teaching in schools, public campaigns, energy labels on appliances and clear information on bills, so that people know which actions actually matter and can see the effect of what they do. | Awareness changes behaviour more slowly and less reliably than price or law does, and the effect fades when the campaign stops. |
| (f) Transport policies | Investment in buses, trams and rail; cycle lanes and pedestrian areas; congestion charges and parking restrictions; fuel taxes; car sharing; incentives for electrically propelled vehicles; planning that puts housing near workplaces. Moving people out of individual cars cuts energy use per journey sharply. | Public transport is expensive to build and must be frequent and reliable before people give up cars. Charges and taxes fall hardest on those with the least choice, particularly in rural areas with no alternative service. |
| (g) Battery storage | Large batteries store electricity when generation exceeds demand and release it when demand exceeds generation. This is the direct answer to the intermittency of wind and solar: it lets a grid use a much higher share of renewables without keeping fossil-fuel stations running as back-up. Smaller batteries do the same job for a single household with solar panels. | Batteries are expensive, store a limited amount for a limited time, and gradually lose capacity. Manufacturing them requires mined lithium, cobalt and nickel, with the extraction impacts of 1.2.4, and end-of-life recycling is still developing. |
| (h) Development of new energy resources | Research into, and investment in, resources not yet in wide use — the four named in 1.5.2 below. Reduces dependence on finite resources and can lower emissions. | Research is slow and expensive, and there is no guarantee a technology will work at scale or ever become cheap enough. New infrastructure has to be built for it. |
1.5.2 The four new energy resources you must know
| Resource | How it works | The honest assessment |
|---|---|---|
| (a) Blue hydrogen | Hydrogen fuel produced from natural gas. Burning the hydrogen afterwards produces water rather than carbon dioxide. | It starts from a finite fossil fuel, and carbon dioxide is released during its production, so the emissions are moved rather than removed unless they are captured and stored. It uses existing gas infrastructure, which makes it quicker and cheaper to introduce than green hydrogen. |
| (b) Green hydrogen | Hydrogen fuel produced using renewable resources — renewable electricity is used to split water into hydrogen and oxygen. Burning it produces water only. | Genuinely low-carbon across the whole chain, and it stores renewable energy in a form that can be moved and kept, which helps with intermittency. But it is expensive, a lot of energy is lost in making it and using it again, and it needs a large supply of spare renewable electricity to exist first. |
| (c) Ground source heat pumps | Transfer of heat from the ground for heating. Pipes buried in the ground carry a fluid that absorbs heat from the soil or rock, which is at a fairly steady temperature all year; a pump raises that heat to a useful temperature for the building. | Very efficient, because it moves existing heat instead of generating it, and the ground temperature barely changes with the seasons so it works in winter. But installation means digging or drilling, so it costs a lot up front and needs land, and it runs on electricity, so its emissions depend on the grid. |
| (d) Air source heat pumps | Transfer of heat from the air for heating. A unit outside the building absorbs heat from the outside air — there is usable heat in air well below freezing — and transfers it indoors. | Much cheaper and easier to fit than a ground source pump, with no digging, and it can be retrofitted to most buildings. But efficiency falls as the outside air gets colder, which is exactly when the heating is needed most, and the outdoor unit makes some noise. |
Blue and green hydrogen in one line each
Blue = from natural gas. Green = from renewables. Both burn to give water. The colour tells you where the hydrogen came from, not what comes out of the exhaust — and that is exactly the distinction an examiner is testing.
A heat pump does not make heat
Say transfers heat, not “produces” or “generates” heat. The syllabus wording is “transfer of heat from the ground/air for heating”, and the reason a heat pump is efficient is precisely that it moves heat that is already there rather than making any. Get that verb right and the definition mark follows.
1.5.3 Discuss: benefits and limitations of these strategies
| Benefits | Limitations |
|---|---|
| Finite resources last longer, and a country importing less fuel gains security of supply and is less exposed to price shocks and political disruption. | Almost every strategy costs money before it saves any, and the households and countries that would gain most from insulation and efficient devices are usually those least able to pay for them. |
| Lower fuel use means fewer emissions of carbon dioxide, sulfur dioxide and particulates, so air quality and health improve alongside the climate benefit. | Making the equipment — panels, batteries, heat pumps, electric vehicles — itself uses energy and mined minerals, so the saving over the whole life cycle is smaller than the saving at the point of use. |
| Households and businesses save money on bills once the initial cost is repaid, and insulation and efficient devices go on saving for many years with no further action. | Payback times can be long, and people move house or replace equipment before they see the return, which weakens the incentive to invest. |
| Battery storage and new resources let a grid take a much higher share of renewables without keeping fossil-fuel stations idling as back-up. | Storage is still expensive and limited in capacity, and some new resources may never become cheap enough at scale — research can fail, and there is no guarantee of a return. |
| Transport policies reduce congestion, noise and urban air pollution as well as energy use, so the benefits reach people who do not own a car at all. | Charges and fuel taxes fall hardest on those with the fewest alternatives, and public transport has to be built and running reliably before people will give up private vehicles. |
| Education and labelling are cheap, reach large numbers of people, and support every other strategy by making people aware of what is worth doing. | Awareness on its own changes behaviour slowly and inconsistently, which is why education generally has to be combined with price signals or legislation to work. |
Who bears the cost, and when
The pattern across the whole of 1.5 is the same: the cost is paid now, by the household or the country installing it; the benefit accrues later, and partly to everyone else. That mismatch is the reason governments use subsidies, taxes and legislation instead of waiting for people to act — and saying so is very often the judgement mark in a “discuss” answer.
Worked example
A city plans to replace its diesel buses with electrically propelled buses. Discuss the benefits and limitations of this decision. [6]
Benefits
Electric motors convert a much larger share of their energy into movement than diesel engines do, so less energy is used per kilometre. There are no exhaust emissions at street level, so urban air quality improves where people actually breathe — less particulate matter and no sulfur dioxide or nitrogen oxides from the vehicle. The buses are quieter, which reduces noise pollution. And the city reduces its consumption of a finite imported fuel.
Limitations — and this is where the marks are lost
The buses are only as clean as the electricity charging them: if the grid is coal-fired, the emissions have been moved from the street to the power station rather than removed. Buying the fleet and building charging infrastructure is expensive up front. Batteries need mined lithium and cobalt, with the extraction impacts of 1.2.4, and they lose capacity and must eventually be disposed of or recycled. Range and charging time may limit how the buses can be scheduled.
The judgement
The local air-quality benefit is immediate and certain; the climate benefit depends entirely on how the electricity is generated. So the decision is strongest in a city with poor air quality and a low-carbon grid, and weakest where the grid is coal-fired — in which case the two changes need to be made together.
Both columns, then a conditional judgement: the answer depends on the electricity mix, and saying so is what earns the evaluation mark.
Source EFigure 1.5A — six energy measures for one house: saving against cost
This is a dual-axis chart: the bars belong to the left axis and the diamonds to the right one. Check which axis a series belongs to before you read any value off it. The figure is the evidence for 1.5.1 — insulation, energy-efficient devices and reducing consumption — and for the discussion in 1.5.3.
Write every part out before you open the model answer. Reading a model answer you have not attempted teaches you almost nothing.
Source E — part (a)
Read Figure 1.5A. Which measure saves the least energy each year?
The shortest bar is the refrigerator at 250 kWh. Notice that it is also one of the more expensive measures, which is the whole point of the figure — the size of the saving and the size of the bill are two different questions, and a strategy question wants you to weigh both.
Source E — part (b)
Read the diamonds in Figure 1.5A. Which measure costs the most to install?
The diamonds are read against the right-hand axis, and the heat pump sits at $9000, an order of magnitude above everything else. Reading a diamond against the left-hand axis is the classic dual-axis mistake: check which axis a series belongs to before you read any value off a graph with two scales.
- (c)Describe the relationship between how much energy a measure saves and how much it costs to install. [3]
- (d)Electricity costs $0.20 per kWh. Calculate the payback time for loft insulation. Show your working. [3]
- (e)Explain why a household on a low income might fit draught-proofing and LED lighting but not a heat pump. [3]
- (f)Discuss the benefits and limitations of relying on energy-efficient devices alone to manage a country’s demand for energy. [6]
Model
Model answer — Figure 1.5A, parts (c) to (f)
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(c) The relationship
There is no simple relationship, and saying so clearly is the answer — a describe question does not oblige you to invent a trend. The measure with the largest saving is also the most expensive (the heat pump, 3200 kWh for $9000), which suggests a positive link, but the refrigerator breaks it completely: it saves the least of all, 250 kWh, and still costs $600, more than loft insulation at $450 which saves 1800 kWh. So cost rises broadly with saving across the insulation measures but the appliances do not fit the pattern.
(d) The calculation
Annual saving in money = 1800 kWh × $0.20 = $360 per year. Payback = cost ÷ annual saving = 450 ÷ 360 = 1.25 years, which is about fifteen months. Do the same for the heat pump and the contrast is the point of the figure: 3200 × 0.20 = $640 a year, and 9000 ÷ 640 = 14.1 years.
(e) The explanation
The barrier is the money needed up front, not the size of the saving. Draught-proofing costs $120 and LED lighting $90, so a household can pay for them out of an ordinary month’s budget and is repaid within about a year and a half. The heat pump costs $9000, which usually means borrowing, and takes about fourteen years to repay itself, so a family that may move house, or that cannot borrow, will not commit to it however sensible it is over the life of the building. This is the standard reason governments offer grants or loans for the large measures and leave the small ones to households.
(f) The discussion
Benefits. Efficiency cuts the energy needed for the same service, so it lowers bills and emissions at once; the cheap measures pay for themselves in a year or two, so they cost the country almost nothing; and they work with the buildings and appliances that already exist rather than waiting for new power stations. Limitations. An efficient device lowers energy per hour, not energy per year — if people use the appliance more because it is cheap to run, part of the saving disappears. The savings are one-off: once every loft is insulated the measure cannot be repeated. The largest measures have paybacks of a decade or more, so uptake depends on income. And efficiency cannot meet new demand from a growing population or a growing economy. Judgement. Efficiency is the cheapest strategy per unit of energy saved and should come first, but the syllabus lists eight strategies for a reason: reducing consumption, education, transport policies, storage and the development of new resources all have to run alongside it, because efficiency alone slows the growth in demand rather than reversing it.
Checkpoint 1.5
Answer, then read the explanation even when you were right.
Your Score
0 / 11
Question 1
How does loft insulation reduce the energy a house uses?
Insulation is a barrier to heat transfer, so less heat is lost and the heating runs for less time to hold the same temperature. A describes a solar panel. C would violate what you know about energy transfers — nothing converts stray heat back into electricity in a loft. D describes a thermostat or timer, which is a different kind of control.
Question 2
What is the main purpose of large-scale battery storage on an electricity grid?
Storage solves a timing problem: renewable output and demand do not peak together, and a battery moves the supply to when it is wanted. A confuses storing with generating — the turbines produce no more than before. C invents a function. D is the reverse of the truth, since batteries are a reason more of those metals are mined.
Question 3
Blue hydrogen and green hydrogen differ in which way?
The colour describes the origin, not the exhaust: both burn to give water, and the syllabus defines blue as produced from natural gas and green as produced using renewable resources. A gets the chemistry backwards for both. C invents a difference in use. B reverses the classification — blue starts from a finite fossil fuel.
Question 4
Why is a ground source heat pump usually more effective in winter than an air source heat pump?
Below a metre or so the ground barely notices the seasons, so the pump has a steady source; outside air gets coldest exactly when heating is needed most. B is wrong about the mechanism — the ground stores heat, it does not generate it. C is false, since both types run on electricity. A overstates a real trend into a false absolute, since air source pumps work below freezing, just less efficiently.
Question 5
Which is a genuine limitation of replacing petrol cars with electrically propelled vehicles?
The two honest limitations are the extraction impacts of battery metals and the fact that the vehicle is only as clean as the electricity charging it. A reverses the efficiency comparison. B reverses the emissions comparison at street level. D is simply false, and is the opposite of the strongest argument in favour.
Question 6
A government funds new tram lines and introduces a congestion charge in the city centre. This is an example of
Both measures are transport policy: one provides an alternative, the other prices the private journey. C would be a campaign or a school programme, not a charge. B refers to getting more from resources already in use, such as upgrading a power station. D refers to the four resources in 1.5.2, none of which is a tram.
Question 7
Which statement is the strongest argument against relying on education alone to conserve energy?
The gap between awareness and behaviour is the honest weakness, and it is why education is normally paired with price signals or legislation. B is false: education is cheap per person, which is one of its strengths. C is invented. D contradicts the first strategy in the list, which works precisely because reduced consumption does lower demand.
Question 8
Why does the syllabus list “exploiting existing energy resources” as a management strategy?
Better recovery from known fields, higher power-station efficiency, lower transmission losses and use of waste heat all mean more useful energy from the same resource. A is contradicted by the syllabus itself, which lists developing new resources as a separate strategy. B misclassifies both. D treats one strategy as a substitute for the others, when the list is meant to be used together.
Question 9
A family fits LED bulbs and then leaves them switched on far longer than the old ones. Which point does this illustrate?
An efficient device lowers the energy used per hour, not the energy used per year, and behaviour decides the rest. That is why reducing consumption is listed as a strategy in its own right alongside energy-efficient devices: the two are not the same idea, and a strategy answer that offers only better technology has covered half the objective.
1.6 Fracking
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▶ Watch: fracking
Opens on YouTube in a new tab. None of these is an 0680 lesson: one is TED-Ed, three are news or agency documentaries and two are general explainers. They are useful for the argument in 1.6.2, and several go well beyond the syllabus into drilling technique — 1.6 asks you only to define fracking and to discuss it. Watch for the two columns of the argument, not for engineering detail.
1.6.1 The definition, and why the technique exists
Learn this exactly
Fracking is the extraction of natural gas or petroleum from shale rock by hydraulic fracturing.
Three things must be in it: natural gas or petroleum, shale rock, and hydraulic fracturing. Leave out “shale” and you have described drilling in general; leave out “hydraulic” and you have lost the mechanism.
Now connect it back to 1.1.4, because that is where the understanding is. Shale is a sedimentary rock that is impermeable — its clay particles are so fine and flat that they leave almost no connected pore spaces. Oil and gas formed within the shale cannot flow through it, so an ordinary well drilled into shale produces very little. That is precisely why the gas is still there after millions of years, and why you have to break the rock to release it.
The technique, in order: a well is drilled down to the shale layer and then turned to run horizontally through it, so that a single well pad reaches a long section of rock. A mixture of water, sand and chemicals is then pumped down at very high pressure. The pressure fractures the shale, opening a network of cracks. The sand grains lodge in the cracks and hold them open when the pressure is released, so that gas or oil can flow through the new cracks into the well and up to the surface. The fluid that returns up the well — the flowback — contains the added chemicals plus salts and other substances picked up from the rock, and has to be treated or disposed of.
Background, not required. Sub-topic 1.6 contains exactly two objectives: define fracking (1.6.1) and discuss it (1.6.2). Horizontal drilling, the sand and the flowback are set out above because the discussion does not make sense without them, not because you can be asked for them in their own right. Learn the definition and the two columns; treat the engineering as context.
A good sentence to practise “explain” on
The sand grains prop the fractures open after the pressure is removed, so that the gas can keep flowing; without the sand the cracks close again and the well stops producing. That is a because-and-so-that answer, which is exactly what explain means, and it is worth writing out once for the practice. Be clear, though, that the proppant itself is background — 1.6 asks only for the definition and the discussion, so the marks live there.
1.6.2 Discuss: benefits and limitations of fracking
This is the most politically loaded objective in Topic 1, and it is therefore the one where a one-sided answer is punished most clearly. Cambridge is neutral. The mark scheme has two columns and expects a judgement that names who gains, who bears the cost, and over what timescale. Learn both columns; do not learn an opinion.
| Benefits | Limitations |
|---|---|
| Access to reserves that were previously unobtainable. Large quantities of gas and oil are held in shale and could not be extracted by conventional drilling at all, so fracking increases the total resource available. | It is still a finite fossil fuel. Burning the gas releases carbon dioxide, so fracking extends the use of fossil fuels rather than replacing them, and investment in it may delay the development of renewable alternatives. |
| Energy security. A country with shale reserves can generate its own gas instead of importing it, which reduces exposure to price shocks and to disruption of supply from other countries. | Very high water use. Millions of litres of water are needed per well, which competes with agriculture and domestic supply — a serious objection in dry regions, which is where several shale basins are. |
| Cheaper gas. Increased supply lowers gas prices for households and industry, which reduces fuel poverty and lowers manufacturing costs. | Risk to water supplies. The fracking fluid contains chemicals, and the flowback returns with dissolved salts and other substances. If a well casing fails or waste is not handled properly, groundwater and surface water can be contaminated. |
| Gas can displace coal. Burning gas rather than coal for the same electricity produces roughly half the carbon dioxide and far less sulfur dioxide and particulate matter, so replacing coal-fired generation improves air quality and lowers emissions. | Methane leakage. Methane escaping from wells and pipelines is itself a powerful greenhouse gas, and enough leakage can offset the advantage gas has over coal. |
| Employment and local income. Drilling creates jobs and brings contracts to local suppliers, and companies and governments receive taxes and royalties. | Small earth tremors. Fracturing rock at high pressure has been linked to small earthquakes near some sites. They are usually too weak to damage buildings, but they cause real public concern and have led to fracking being suspended or banned in several countries. |
| Bridging supply. Supporters argue gas can cover demand while renewable capacity and storage are built, because gas power stations can be turned up and down quickly to balance intermittent wind and solar. | Local disturbance and land use. Well pads, access roads, heavy lorry traffic, noise, dust and floodlighting industrialise a rural area. Shale wells decline quickly, so many wells must be drilled to maintain output, spreading the disturbance further. |
The judgement, in the four moves
Benefit: more gas, produced domestically, cheaper, and cleaner than the coal it may replace. Limitation: water use, contamination risk, tremors, methane leaks, and it is still a fossil fuel. Who bears the cost: the water, traffic, noise and tremor risk fall on the local community and its farmers, while the tax revenue and the security of supply are national. Timescale: individual shale wells produce for a few years, so the gain is short-lived, while contaminated groundwater and the carbon dioxide released last far longer. That paragraph, adapted to whatever the source material says, will earn the evaluation marks in almost any fracking question.
Applied question
A country imports 70 % of its gas. A company applies to frack a shale deposit beneath farmland in a region where rainfall is low and farmers already irrigate from boreholes. Evaluate the application. [8]
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Evaluate is the highest of the command words: give both sides, weigh them against each other, and reach a supported conclusion. Eight marks means roughly three points each way plus a developed judgement, and the details in the question — 70 % imports, low rainfall, existing boreholes — are there to be used, not decorated round.
The case for
Importing 70 % of its gas leaves the country exposed to price rises and to disruption of supply, so domestic shale gas would improve energy security and keep money in the national economy. It would create jobs and generate tax and royalty income in a rural region with few alternatives. If the gas displaces coal in power stations, carbon dioxide emissions per unit of electricity fall by roughly half and sulfur dioxide and particulate emissions fall sharply.
The case against — and use the details given
Fracking needs millions of litres of water per well, and the question tells you rainfall is low and farmers are already drawing on groundwater; the two uses would compete directly, and the farmers have no alternative source. A well casing failure or poorly handled flowback could contaminate the same boreholes, which would affect drinking water and irrigation together. Lorry traffic, noise and well pads would disturb farmland, and because shale wells decline quickly, many wells would be needed. And the gas is still a fossil fuel, so it does not reduce emissions in the long run — it may delay investment in renewables.
The judgement
The national benefits are real but the costs fall almost entirely on one region, and in this particular region water is the binding constraint. A defensible conclusion is that the application should be refused unless water can be supplied from outside the local aquifer, well integrity is independently monitored, and flowback disposal is regulated and enforced — and even then the benefit is a temporary bridge rather than a long-term energy policy. Note that a conclusion the other way can also score full marks if it is argued from the same evidence: what is marked is the weighing, not the verdict.
Source FFigure 1.6A — output and drilling in one shale gas field, 2019 to 2024
Objective 1.6.2 is a discuss, and a discuss answer built on figures beats one built on opinions. This graph carries two series on two different scales, which is exactly how Paper 2 presents a resource that is being worked hard: one line for what comes out, one for the effort going in.
Write every part out before you open the model answer. Reading a model answer you have not attempted teaches you almost nothing.
Source F — part (a)
Read Figure 1.6A. How many new wells were drilled in 2022?
New wells are the dashed line read against the right-hand axis, and the 2022 point sits at 85. The three wrong options are the neighbouring years, so the safeguard is to put your finger on the year first, run it straight up, and only then read across — not the other way round.
Source F — part (b)
In which year was the field’s gas output at its highest?
The solid line peaks in 2023 at 1240 and then falls, even though 90 new wells were drilled in 2024 as well. That gap between drilling effort and output is the thing the figure is really showing, and it is the evidence behind the standard limitation that shale wells decline quickly.
- (c)Describe what happened to the field’s gas output between 2019 and 2024. Quote figures. [4]
- (d)Each new well uses 15 million litres of water while it is fractured. Calculate the water used by the wells drilled in 2024. [2]
- (e)Explain why output stopped rising in 2024 even though 90 new wells were drilled that year. [3]
- (f)Discuss the benefits and limitations of continuing to develop this field. [8]
Model
Model answer — Figure 1.6A, parts (c) to (f)
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(c) The description, with figures
Output rose steeply at first, from 480 million m³ in 2019 to 760 in 2020 and 1010 in 2021. The rise then slowed: 1180 in 2022 and a peak of 1240 in 2023. In 2024 it fell back to 1180. So the shape is a steep rise, a levelling off and then a small decline — and naming those three phases with their years is what a 4-mark describe wants, rather than the single word “increased”. If you are asked for the change in the last year: 1240 − 1180 = 60, and 60 ÷ 1240 × 100 = 4.8 %, a fall.
(d) The calculation
Wells drilled in 2024 = 90, read off the dashed line against the right-hand axis. Water = 90 × 15 = 1350 million litres, which is 1.35 billion litres, or 1.35 million cubic metres. Keep the unit with the number: “1350” on its own is not an answer.
(e) The explanation
A shale well produces most of its gas in its first year or two and then declines steeply, because the fractures drain the rock immediately around them and shale is too impermeable for more gas to flow in quickly. So each year’s new wells have to replace the falling output of every well drilled before them. By 2024 there were enough older, declining wells in the field that 90 new ones could not add more than the older ones lost, and total output fell. This is why the effort line and the output line stop moving together.
(f) The discussion
Benefits. The field produces over a billion cubic metres of gas a year, which is real energy security — gas produced at home is not exposed to import prices or to a pipeline being closed. Gas burnt instead of coal releases roughly half the carbon dioxide and far less sulfur dioxide and particulate matter for the same electricity. Drilling employs people and brings contracts to local suppliers, and the government receives taxes and royalties. Gas stations can be turned up and down quickly, so they can balance wind and solar. Limitations. The water figure from part (d) is the sharpest one: 1350 million litres in a single year competes with farming and domestic supply, and several shale basins are in dry regions. The fracking fluid contains chemicals and the flowback returns with dissolved salts, so groundwater can be contaminated if a well casing fails. Methane leaking from wells and pipelines is itself a powerful greenhouse gas and enough leakage cancels the advantage over coal. The wells decline fast, as the graph shows, so the disturbance — pads, roads, lorries, noise, floodlighting — has to keep spreading to hold output level. And the gas is still a finite fossil fuel. Who bears the cost, and over what timescale. The water use, the traffic and the contamination risk fall on the local community and its farmers; the tax revenue and the security of supply are national. Individual wells produce for a few years; contaminated groundwater and the carbon dioxide released last far longer. Judgement. Continuing is defensible where the gas genuinely displaces coal, where water is not scarce and where regulation of well integrity is enforced; it is hard to defend where any of those three fails, and the graph suggests the field is already past the point where more drilling buys more gas.
Checkpoint 1.6
Answer, then read the explanation even when you were right.
Your Score
0 / 8
Question 1
Which definition of fracking matches the syllabus wording?
C is the syllabus wording, and all three of its parts matter: the fuel, the rock, and the method. A puts the technique on the wrong fuel. B describes conventional drilling, which works precisely because the rock is permeable and needs no fracturing. D borrows the idea of bioleaching from 1.2.2 and applies it where it does not belong.
Question 2
Why must shale rock be fractured before gas can be extracted from it?
This is 1.1.4 doing real work: shale has almost no connected pore spaces, so the gas cannot move, and fracturing creates the pathways. A confuses permeability with hardness — shale is a soft rock. C would be chemistry that does not exist. D imagines a chemical bond where the gas is physically trapped instead.
Question 3
A government is deciding whether to allow fracking. Which statement belongs in the limitations column of a balanced answer?
Water use is a limitation because the volume is very large and it competes with farming and domestic supply, and several shale basins lie in dry regions. The other three are all genuine benefits, and putting a benefit in the limitations column loses the mark even though the statement itself is true. In a discuss answer, sort every point into a column before you write.
Question 4
Which is the strongest environmental objection to fracking in a region where farmers irrigate from groundwater?
The question specifies irrigation from groundwater, so the objection that bites hardest is the one that hits that same resource twice — through the millions of litres consumed and through the risk of contamination. A is a real limitation but it is global rather than specific to this region. C is a genuine but much smaller local effect. D overstates the evidence: the tremors recorded are generally too weak to cause structural damage, which is why the honest objection is public concern rather than collapse.
Question 5
Which is a valid benefit of fracking that an examiner would credit?
Security of supply is one of the main arguments made for fracking and it is creditable. B misclassifies shale gas, which is a fossil fuel and finite. C confuses extracting a fuel with generating electricity, which still needs the fuel to be burned. D states an argument that supporters do not actually make, and it is the sort of overclaim that loses marks in an evaluation.
Question 6
In an eight-mark question asking you to evaluate a fracking proposal, which approach scores best?
Evaluate means weigh both sides and reach a supported judgement, so A is what the mark scheme is built around. C and B are each half an answer and cap at roughly half the marks, however well written. D answers a different command word altogether — that is a “describe” response, and describing the method earns nothing here.