# Waves

• Review of Basic Concepts: Waves are disturbances that move through space and matter, transferring energy from one place to another. They can be classified into two broad categories: mechanical waves and electromagnetic waves.

• Mechanical Waves: These waves require a medium, such as air, water, or a solid material, to travel through. They include sound waves, seismic waves, and water waves.

• Electromagnetic Waves: These waves can travel through a medium, but they don’t need one. They can move through empty space at the speed of light. They include light, x-rays, radio waves, and microwaves.

• Wave Characteristics: Every wave has a number of identifiable characteristics. These include wavelength (distance between successive crests or troughs), frequency (number of waves passing a point in a given time), amplitude (distance from the crest or trough to the equilibrium position), and speed (how fast the wave is moving).

• Reflection, Refraction, and Diffraction: Reflection occurs when a wave bounces off a surface. Refraction is the bending of waves as they pass from one medium to another. Diffraction is the spreading out of waves as they pass through an opening or around the edge of an object.

• Wave Interference: Waves can interfere with each other, resulting in constructive interference (when the waves add together to make a larger wave) or destructive interference (when the waves cancel each other out).

• Polarisation: Polarisation is a property of waves that can oscillate with more than one orientation. Electromagnetic waves such as light exhibit polarisation, as do some types of mechanical waves.

• The Doppler Effect: This is the change in frequency or wavelength of a wave in relation to an observer who is moving relative to the wave source. It’s the reason why a car engine’s noise changes pitch as it moves past you.

• Applications of Waves: Understand the importance and applications of different types of waves in the real world. From communication and music (sound waves), to navigation and weather forecast (radio and microwaves), to medical imaging and cancer treatment (x-rays, gamma rays).

• Wave Diagrams: Practice drawing and interpreting diagrams of waves, labelling wavelength, amplitude, crest, trough, and zero line (equilibrium position).

• Calculations: Be able to perform calculations involving wave speed, frequency, and wavelength using the wave equation: wave speed = frequency x wavelength. Remember to check if your units are consistent before calculating.

It’s important to understand these concepts and be able to apply them to problem-solving scenarios. Use online resources, textbooks, and practise problems to reinforce your understanding.