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.
As an introduction to solids, liquids and gases, the example of bromine (in the first part of the clip) could be used to stimulate discussion about other substances which exist in various forms eg steam, water, ice. Having watched the second part of the clip, children could identify the features of solids, liquids and gases in relation to particle arrangement, making a defining list of the differences between the three states of matter. Children could arrange themselves in groups, to show their understanding of the particle arrangement in solids by linking arms. Act out what would happen to the particles in a solid if they were heated? Pupils could loosely link arms and move around more freely. Finally, ask them to decide what would happen if the liquid was heated. How would the particles behave?