Rock salt is natural salt that is dug out of the ground.

In the UK, there are salt mines in Cheshire and much of this salt is crushed and used to 'grit' the roads in winter when they have ice and snow on them, helping to keep them clear.

Rock salt comes from the remains of prehistoric seas and is a mixture of salt together with sand and rock.

So, your challenge today is to join some young scientists who are investigating how substances can be separated from each other when they're mixed together.

In the first experiment, Robert is trying to extract some pure salt from a lump of rock salt.

You're going to need to bring your knowledge of separation techniques to help Robert.

Things like:

- crushing up lumps to help them to dissolve faster

- using water to dissolve salt

- using a filter to separate the insoluble rock and sand particles

- using evaporation to remove the water from the salt solution.

Remember, Robert is hoping that he will have enough salt to sprinkle on his fish and chips!

Let's get started!