Chapter 1 – Introducing quantum mechanics

Light as a wave

Waves and particles are clearly different – what is light?

Waves diffract

Diffraction is when waves spreads out after going through a narrow gap or past a sharp corner

Particles go in straight lines so don’t diffract

Things that diffract look like waves and light diffracts by bending around sharp edges. This suggests light is a wave.

Waves interfere

Overlapping waves from two sources interfere. There are points where the waves align giving strong variations and there are points where the waves cancel each other out.

Double slit experiment

In 1801, Thomas Young’s double-slit experiment showed the wave nature of light. Light was sent to two narrow slits and interference patterns were seen on the screen.