Why does salt melt ice?

Why does salt melt ice? We’ve experimented with ice and salt before and found that salt does make ice melt, but why does this happen?

why does salt melt ice

The photo above is just a block of ice withe pipe cleaners and straws frozen inside for decoration. You can see that the ice has started to melt where we’ve added salt.

Why does salt melt ice?

Salt lowers the freezing point of water.

Ice melts faster when salt is added as the salt lowers the freezing point of the ice, this is known as freezing point depression. The more salt you add the lower the freezing point.

This interesting feature of salt and ice and can be used for lots of fun and easy experiments.

Making ice cream with ice and salt

Did you know you can make ice cream using milk, salt and ice?

This works because as the ice melts heat is absorbed from the surroundings ( the milk mixture ) making them freeze.

How to make ice cream

See our full instructions for making ice cream with ice and salt here.

This would also make a great taste investigation. Try adding different flavours to the milk and investigate to see whether a friend can guess what each flavour is. You could even add some strong flavours like chilli or garlic!

How to cool a drink quickly

This investigation uses salt to supercool an ice and water mixture making a drink extra cold FAST!

ice and salt experiment

How to make frost

Making frost on a can is easy if you have salt, ice cubes and a tin can. This is our Frosty the Snowman, but you could theme this investigation however you wanted.

How to make a frosty snowman

More ice investigations

Try some painting on ice.

Make some ice decorations

Investigate how to make the best ice hockey puck

Try some colour mixing and make slushy drinks with ice.

Make some baking soda ice cubes!

Rainy Day Mum investigates salt melting sheets of ice and why we grit roads.

Can you think of any more icy investigations?

why does salt melt ice

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