Two methods for demonstrating this to your students. Liquid nitrogen presents a particular set of risks.
Demonstration: This introduces students to the idea that the value of a measurement depends on the nature of that measurement.
Demonstration: Finding the thickness of an oil film enables an estimate of the size of atoms to be made.
Demonstration: This helps students to remember that olive oil molecules stick up out of water like grass on a lawn.
Class practical: Experiments to help a class understand the Estimating the size of a molecule using an oil film experiment.
Demonstration: Using models to support a discussion of the mean-free-path of molecules in a gas, and, perhaps, to lead to a...
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