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age: 16 – 18

Cutting through ice

If you can find small coins of similar size but different materials, such as copper and steel, try to push them into an ice cube: You will note that copper coins are easier to press into ice – and feel colder while doing so.

Learning objective

Some metals conduct heat better than others.

Ice Cubes
Copper and steel coins of roughly the same size
Plastic dish
Student Task

Press coins made from different metals straight into an ice cube.

1. Do you feel a difference? If so, how do you explain this?


There are two main differences to note, namely the ease with which the coins 'cut' through the ice and the time it takes to feel the cold on the fingers. Both effects have the same origin: Differences in the thermal conductivity.

The coins absorb heat from the fingers and transfer it to the ice surface. Copper transfers heat roughly 10 times faster than steel. 'Red' coins (usually steel or zinc covered with copper) therefore feel cold faster – and melt ice quicker – than 'silver' coins (usually made from stainless steel).