They put different bowls of water, some were very cold, others at room temperature, others a bit warm and others hot (not very!). Some students, with their eyes covered had to put their hand into the bowls and share their experience with the rest. They were asked to think how we could measure this in an accurate way. They built up their hypothesis. We agreed that we needed a thermometer to measure the temperature of water! We also explained students the different types of thermometers and their uses.