Lesson Plan

Explain that a photon carries momentum and calculate it using p = h/λ (the de Broglie relation)

Describe the Compton effect and explain how it shows energy and momentum are conserved in photon-electron collisions

Explain how photon momentum accounts for comet tails and how it is used in solar sails

Explain the particle-wave duality of light and why one experiment reveals either particle-like or wave-like behavior, but not both at once

21.3

"While it is strange to think of a massless particle exhibiting momentum, it is now a well-established fact within the scientific community." "For the discovery of this conserved scattering, now known as the Compton effect, Arthur Compton was awarded the Nobel Prize in 1929." "We have long known that EM radiation is like a wave, capable of interference and diffraction. We now see that light can also be modeled as particles—massless photons of discrete energy and momentum. We call this twofold nature the particle-wave duality, meaning that EM radiation has properties of both particles and waves." "$$\mathbf{p} = \dfrac{h}{\lambda},$$ was determined by Louis de Broglie. In this equation, called the de Broglie relation, h represents Planck's constant and λ is the photon wavelength."