Light is the most familiar thing in the world and one of the strangest. For two centuries physicists argued about whether it was a wave or a stream of particles, ran clever experiments to settle it, and ended up with an answer nobody expected: it's both, and neither, depending on how you look. We trace that argument and what it revealed about the deep grain of reality.

You'll come away understanding why the famous double-slit experiment is so unsettling, what a photon actually is, how the colours you see are just a thin slice of a vast spectrum, and why “wave-particle duality” is less a paradox than a hint about how the universe really works.

Talking Science is sponsored by Kinsoft. Visit www.kinsoft.com.au

Further reading: Feynman's QED: The Strange ...