# Introduction to waves

## Summary

Particles don´t spread out, pass through each other, add or cancel... but waves do.

What quantities do we use to model waves? Sound and light are very different but are modelled in the same way.

## Get the basics

#### Properties and quantities

The kinetic energy of a particle travels with the particle, whereas the energy in a wave spreads out.

Quantities used to describe waves include:

• Wavelength
• Frequency
• Wave speed

#### Wave propagation

A wavefront propagates as if it were made of an infinite number of wavelets.

## Stretch for 7

#### Transfer of energy

When a ball hits the surface of a pond, it gives energy to the surface. This energy spreads out. All waves involve the transfer of energy.

#### Wave equation

Speed, frequency and wavelength are related by the formula:

$$v=f\lambda$$

## Test yourself

Use quizzes to practise application of theory.