1. Wave Particle Duality

2. Wave Particle Duality
Visible light is one example of an electromagnetic wave…
But there are also light particles called photons…
So is light a wave or a particle?
This is called the wave particle duality – light has properties of both waves and particles!

3. Evidence that Light is a WAVE
Light has NO mass!
Diffraction – light spreads out when it moves through an opening or past a barrier

4. Evidence that Light is a WAVE
Refraction – light bends when it enters a new medium
Interference – light waves can combine to create a pattern of bright and dark areas

5. Evidence that Light is a WAVE
Polarization – light can be filtered to vibrate in a specific direction
Doppler Effect – the frequency of light changes when the source of the light wave is moving

6. Evidence that Light is a PARTICLE
Light can travel through a vacuum (empty space)
Photoelectric Effect – shining a light on certain types of metal causes electrons to be released from the atoms in that metal