An investigation into the effect of ice on temperature. Three glasses contain varying amounts of ice and a thermometer. The temperature is the same in all three glasses. Just because some contain more ice does not mean that the temperature is lower than zero degrees Celsius. The temperature will not rise above zero until the ice is completely melted.
This clip will help to introduce melting points. Pupils could put ice, chocolate and butter in warm water baths and record the temperature of each material at one minute intervals until they melt. Children could then plot their results in line graphs to show that the temperature of each material stays the same whilst they are melting.