• Question: Is Light a Wave or a Particle?

    Asked by umut to Mike, Suze on 24 Jun 2011.
    • Photo: Mike Dodd

      Mike Dodd answered on 24 Jun 2011:

      It’s actually both. Quantum mechanics describes that light can exist as a wave and a particle at the same time. Although I really don’t understand it 🙁

    • Photo: Suze Kundu

      Suze Kundu answered on 24 Jun 2011:

      Hello Umut!

      Light can act as both a wave, and as a particle. This is known as ‘wave-particle duality’, and was something that was discovered by Einstein amongst others, so you’re in pretty good company in asking this question!

      When it is thought of as a particle, it is like a packet of light with a specific energy. It’s a bit like the work that I’m doing, where packets of specific energy can drive my water splitting reaction.

      It has also been shown to act as a wave though, as if you try and squeeze light through a small gap, the waves that come out of the other side are curved, and so have been diffracted. Here’s a picture to explain that better:

      So light is therefore both a wave, and a particle! Hope that answers your question Umut, but if you want more information, give me a shout, and we can talk about it.

      Mike, don’t worry. No one understands quantim mechanics. It was my worst Uni module!