# Wave phenomena

On this page we will examine the wave phenomena of reflection, refraction, interference, diffraction and polarisation, as well as the concept of standing (or stationary) waves.

To show these in a visual way we will use a ripple tank simulation. Wave simulations use the same mathematical equations that are used to model real waves. Therefore they have have the same properties.

Key Concepts

Reflection

When a wave hits a boundary or change in medium, it reflects back. Each point on the boundary behaves like a small wavelet source.

the angle of incidence = the angle of reflection

Refraction

When a wave travels into a more dense medium, it slows down. This causes the wave to change direction.

$${\sin i\over \sin r}={v_1\over v_2}$$

Essentials

Interference

When two balls collide, they bounce off each other. When two waves collide, they pass through each other.

Where the waves overlap the amplitudes add, this is called superposition. This results in interference effects.

Diffraction

When a wave passes through an opening in a barrier, it spreads out. Diffraction is optimised where the width of the opening is approximately equal in size to the wavelength.

Polarisation

A wave in a guitar string, like many examples of waves, oscillates in all directions.

A polarised wave only oscillates in one direction.

Standing waves

A standing wave is formed when two waves, of equal frequency and amplitude, travelling in opposite directions interfere.

Test Yourself

Use quizzes to practise application of theory.

Exam-style Questions