Planet Earth is covered in rocks that have been formed in different ways. Some come from volcanic activity and others are formed from layers of sediment building up on the sea bed. Sometimes, one type of rock can be converted to another type by high temperature or pressure. These are metamorphic rocks.

Within the different categories of rocks, there are many different chemical compounds. For example, white chalky cliffs are made of calcium carbonate. Granite contains a compound called silicon dioxide.

The compounds that make up a rock and the way those compounds are arranged can give us lots of information about where that rock came from and how it was made. Some rocks are made from ancient deposits of minerals from living creatures. Scientists study these as they can give us clues about how life started on Planet Earth.

Experiment with rocks!

Collect some different types of rocks and try and describe them. How are they different? Do they have different colours? Do they feel different?

Some rocks contain different materials all squashed together. These can be chunks of different crystals or lots of layers. Can you make your own version of a rock like this using playdough or chewy sweets? Have a look at this video for inspiration!

Mars Rocks

The Perseverance rover touched down on Mars in February 2021. The goal of the mission is to search for clues that life once existed on Mars. One of the ways that Perseverance will do this is to study the rocks on the surface of Mars.

Perseverance will use X-rays as one way of studying the rocks that it collects. Here is a video explaining how this will work…

What other solids can we study with X-rays?

X-rays are useful for learning about rocks. But they’re also useful to scientists studying lots of different types of solids! Learn about how X-rays are used to study batteries in this video!

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