Science at Home
Year 4 would like to share an easy ice cube experiment which you can do at home.
- Fill the glass to the top with water.
- Cut a piece of string around 20 centimetres long.
- Place a big ice cube in the water. It will float.
- Lay the string across the ice cube and glass.
- Cover ice cube and string with a layer of salt.
- Leave for one minute.
- Carefully pick up the ends of the string.
Congratulations! You picked up an ice cube with a piece of string. Challenge your friends and parents. See if they can work out how you did it.
Salt lowers the freezing point of water to below 0 degrees Celsius. When you added salt to the ice cube, the salt lowered the melting point of the ice. The salt is in a thin layer, so it melts a thin layer on top of the ice cube. The water cooled down further and re-froze around the string.
We use salt in winter to prevent roads from getting icy. The salt lowers the melting point of ice and stops roads from becoming icy and dangerous.