Big Idea: All matter is made of small particles and this can explain many of its properties. More info...
Class practical: As with a spring, force is required to compress or to expand a gas.
Demonstration: This experiment is quite elaborate, but it yields quantitative results. A beam balance weighs the pressure.
This episode looks at Brownian motion as evidence for the particulate nature of matter, and the macroscopic gas laws.
Recognising and celebrating outstanding contributions to the field of physics education.