Did you know - the Earth is a rocky planet?  All of its surface is covered by rock.

You may not always be able to see the rock. It might be hidden beneath a layer of soil or beneath the water of an ocean, but dig down far enough and it is there.

We can particularly see evidence of the rocky Earth where great mountains push up into the sky.

There are many types of rock. They are not all the same and they have lots of different characteristics:

- some are hard (cannot be scratched by a knife) while some are soft (a knife leaves scratches)

- some are permeable (let water soak through them) while others are impermeable (no water soaks through)

- some are more soluble in water than others - that means that water can dissolve parts of the rock, wearing it away and turning it into a solution.

These characteristics help to sort out what certain types of rock can be used for: building, roads, statues, roofs and so on.

Let's use this activity to test what you know about rocks.