A demonstration of the behaviour of particles as solids, liquids and gases. An experiment shows bromine gas being heated in a sealed tube. Cartoon pictures demonstrate the behaviour of particles in their three states - solid, liquid and gas. Solids are shown to have a rigid structure of particles vibrating at fixed points. Liquid is shown with no fixed shape and particles moving around. Gas particles are shown to move randomly and rapidly to fill spaces.
Students could discuss the differences between the properties of solids, liquids and gases and how matter changes as it moves between states. Students could first describe the properties of an ice cube, water in a pan, and steam. They could then be given marbles to represent matter particles and show how the behaviour and position of matter particles changes in different states. What happens when water is heated? Students could move the marbles further apart. What about when water is frozen? Students could move the marbles close together. This demonstrates it is not the particles which changes in each state, it is the space surrounding them.
Students could build on these concepts with a game. They could appoint a caller to shout out a state (either solid, liquid or gas) and students could try to move around as the particles would. For example, if the caller shouts “gas”, everyone could move to fill the entire room and jump around quickly. If the caller shouts “solid”, everyone could gather together and move slowly on the spot.