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Episode 505: Preparation for wave-particle duality topic In the first quarter of the twentieth century physicists began to realise that particles did not always behave like particles – they could behave like waves. They called this wave-particle duality. This theory suggests that there is no basic distinction between a particle and a wave. The differences that we observe arise simply from the particular experiment that we are doing at the time. As with quantum theory, this is a section of the course that candidates will find completely new. They are unlikely to have already met the wave nature of particles or the wave nature of electrons bound within atoms. Episode 506: Particles as waves Episode 507: Standing waves Main aims Students will: 1. Understand that electron diffraction is evidence for wave-like behaviour. 2. Use the de Broglie equation. 3. Identify situations in which a wave model is appropriate, and in which a particle model is appropriate, for explaining phenomena involving light and electrons. 4. Use a standing wave model for electrons in an atom. Prior knowledge Students should have an understanding of wave phenomena, including diffraction and interference. They should know how to calculate momentum. This work follows on from a study of the photoelectric effect. Where this leads These episodes merely skim the surface of quantum physics. For students who wish to learn a little more, here is some suggested reading: The new quantum universe; Tony Hey and Patrick Walters; CUP Quantum physics: An introduction; J Manners; IoPP You can extend the idea of electrons-as-waves further, to the realm of the atom. 1