Glass is a special material which can be melted into a liquid at high temperatures. It can then be blown or shaped. When the glass cools down, it stiffens and eventually becomes hard.
This clip could introduce the concept of melting. Children could investigate the melting points of different materials such as ice, water, chocolate and jelly using baths of hot water and measuring the temperatures at which they melt. Children could also research the melting points of different metals and materials and record their findings in the form of a bar graph.