How a Fossil Is Made: Free KS2 Worksheet (Ages 7 to 8)

What this worksheet teaches

This worksheet introduces the idea that fossils are the preserved remains or traces of living things, formed over a very long time. Children learn the simple sequence at the heart of the Year 3 curriculum: an animal dies and sinks to the seabed, its soft parts rot away, layers of mud and sand bury the hard parts such as bones or shells, and over millions of years the layers slowly turn to rock. Much later, the sea, wind and rain wear the rock away and the fossil is uncovered, which is the last picture on the sheet. The four-stage picture gives children a clear visual model so they can talk through and write about each step with confidence.

Why fossils sit within the rocks topic

In the National Curriculum, fossils are taught as part of the wider Year 3 unit on rocks. This is because most fossils are found in sedimentary rock, which itself forms from layers of mud, sand and other material that build up and harden over time. Linking the two ideas helps children understand why fossils are usually found in layers and why deeper layers are older. It is worth reminding children that only hard parts — bones, teeth and shells — tend to survive, while soft parts almost always rot away, which is why we so rarely find fossils of jellyfish or worms.

Key vocabulary to introduce

Building the right vocabulary helps children explain the process clearly. Useful words for this topic include fossil (the remains or trace of a living thing preserved in rock), sediment (small pieces of mud, sand and rock that settle in layers), layer (a band of rock or sediment), decay or rot (when soft parts break down), and millions of years (the very long time the process takes). Encourage children to use these words when they write their answers rather than relying on everyday phrasing.

How to use this sheet at home or in class

Begin by talking through the picture from left to right, asking children to describe what is happening in each stage before they write anything. They can then colour the scene — perhaps using blue for the sea, brown for the mud and grey for the finished rock — which reinforces the idea that the surroundings change as time passes. Finish with the writing task, where children describe each of the four pictures in their own words. A common misconception is that a fossil is always the actual bone; explain that, over a very long time, minerals in the water often replace the bone bit by bit, so many fossils are really rock in the shape of the bone. To extend the activity, ask why we mostly find the hard parts of animals and what a fossil can tell us about creatures that lived long ago.

Frequently asked questions