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What is a fossil?

A fossil is the preserved remains or traces of a dead . Fossils are formed through a process with multiple stages called fossilisation, and this takes place over many, many years.

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Explaining fossilisation

Fossilisation only happens in certain conditions. That's why not every organism that dies becomes a fossil!

Watch: The fossilisation process

Dig deep to uncover the facts about fossils.

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The conditions for fossilisation

Image caption,
If you leave an apple core outside, it will slowly rot away.

It’s very rare for living things to become fossilised. After most animals die, their bodies usually away and nothing is left behind.

However, under certain special conditions, a fossil can form.

Image caption,
If you leave an apple core outside, it will slowly rot away.
 A little dinosaur
Image caption,
It’s not just animal and plant remains that can be fossilised. Things like footprints, burrows, eggs and even poo (called coprolite) can be fossilised too.

After an animal dies, the soft parts of its body . The hard parts, like the skeleton, are left behind. They become buried by small particles of rock called sediment.

As more layers of sediment build up on top, the sediment around the skeleton begins to compact and turn to rock.

The bones then start to be dissolved by water that passes through the rock. in the water replace the bone, leaving a rock replica of the original bone called a fossil.

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Activities

Test your knowledge of fossils with the activities below.

Activity 1: Order the process of fossilisation

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Activity 2: Fossilisation quiz

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Activity 3: Drawing a fossil

Get a pen and paper - it's time to draw!

  1. Draw a line down the middle of your paper.
  2. On one half, draw an animal's body on the day it is buried in the ground. On the other half, draw its fossil after 2 million years.
  3. Write one sentence to describe how the animal's body has changed.
  4. Write a second sentence to describe the type of soil that surrounds the body.
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