This round of science club sessions began by investigating melting ice. Children found that adding salt to ice-cubes led to them melting quicker and producing a much colder slush, compared to ice-cubes with no salt on them. This is due to salty water having a lower freezing point than water, which means that the ice-cubes covered in salt want to melt but they still have to draw in heat energy from their surroundings to achieve this melting. Consequently, the surroundings become very cold.
The children used this learning to make home-made ice-cream without a freezer. The ingredients were shaken in a small bag for about 10 minutes whilst being surrounded by an ice / rock salt mixture. Much to the children’s delight, they succeeded in making delicious tasting, vanilla ice-cream.