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