Topic 3: Waves

Waves are everywhere — from the ocean to your phone signal. Transverse vs longitudinal, the key terms (wavelength, frequency, amplitude, period), wave speed = frequency × wavelength, and what happens when waves bounce, bend, and spread out (reflection, refraction, diffraction).

How light bounces off mirrors and bends through glass — and why rainbows exist! Reflection and the law of reflection, refraction (Snell's law, refractive index), critical angle and total internal reflection (fibre optics!), converging lenses, ray diagrams, and dispersion of white light.

From radio waves to gamma rays — they're all the same type of wave, just different frequencies. Learn the order (radio, microwave, infrared, visible, UV, X-rays, gamma), their everyday uses, their dangers, and how they're used in communication.

Sound is a wave you can hear but can't see — it needs a medium to travel through. Sound as a longitudinal wave, speed of sound, echoes, how frequency relates to pitch and amplitude to loudness, ultrasound and its clever uses, and the human hearing range (20 Hz – 20,000 Hz).