Ask students to draw particle diagrams of solids, liquids and gases. Around the outside of each diagram ask students to write the properties of each. Students are then given syringes of air, water and sand. No explanation is given. Can they link this experiment to what they have written? (Gases can be compressed but solids and liquids cannot.) To prove their understanding students can answer the following question: "Why do we use brake fluid in cars, not brake gas or brake solid?"