States of matter > solids

In this class practical students take the temperature of stearic acid at regular intervals as they heat and cool it. They can observe the

Ice cubes are floated on cooking oil, and students observe what happens to the liquid 

Pieces of solid air freshener are heated in a hot waterbath and the vapour caught by cooling with ice. No liquid will be observed so students will be able to appreciate that a solid has turned directly to a gas without passing

This is a very quick demonstration showing that two