In Primary 5 we have been learning about Solids, Liquids and Gasses. We have carried out experiments to study them. So far we have created filters to clean water, made salt crystals and today we created our very own lava lamps. Oil and water have different densities and thus oil will sit above water. We use food colouring which mixes with the water to make a pretty colour. We then added alka seltzer tablets which react with the water to make a gas, which then rises up through the oil as bubbles.