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DISCLAIMER
Neither Future Publishing nor its employees can accept any liability for any adverse effects experienced during the course of carrying out these projects or at any time after. Always take care when handling potentially hazardous equipment or when working with electronics, and follow the manufacturer’s instructions.
SUMMARY
This is a fun experiment on a hot day – or any day for ice cream lovers – but how exactly does it work to quickly freeze the milk and cream? The salt in the large bag is a catalyst that lowers the freezing point of water to below that of the large bag with just ice cubes inside. When the temperature is low enough, the molecules in water slow down, meaning they can line up to form solid ice crystals, or ice cubes.
When they are outside the freezer and in the bag, the ice cubes will start to melt. The presence of salt prevents the water from refreezing at the surface of the ice cubes, helping to speed up the melting process. This increases the rate at which the ice cream forms because the ice absorbs the surrounding heat from the ice cream mixture as it melts. This causes the mixture to freeze, forming your ice cream in the smaller bag.