Fossils

The type and position of fossils can be used to estimate the age of layers of soil.

How it works

Pull out each drawer (earth layer). Check which index fossil is inside.

Things to try or ask around the exhibit

• How can you tell time from fossils?
• How long ago was the plant or animal alive?
• How old is this layer of earth?

Background

When some plants and animals die, they decompose but leave traces of their shape. These are called fossils. Fossils of plants and animals that are known to have lived for certain periods of time are called index fossils. When these index fossils are found in a layer of earth, (anywhere in the world) they are used to judge the age of the layer in which they are found.

Finding the science in your world

When archaeologists are excavating a historical site such as an ancient ruin, they often find layers of rubbish discarded by former inhabitants. By plotting the position of items in layers, the archaeologists can estimate which items are older, or more recent, although items can be disturbed in the layers if they are washed away by water, or moved by animals.