To understand why archaeologists say certain things about prehistory it is important to understand how archaeologists work. Many museums and heritage sites try to do this by running sandpit digs. So often a sandpit dig is just about finding objects, but here at Schools Prehistory we think it’s important to know that archaeologists try to work out where the artefacts were originally deposited in the ground.

So today our Director, Kim Biddulph, ran a little experimental dig with a couple of four year olds. Not exactly the equivalent of a Year 3 class, but with a bigger sandpit and older kids it could work for half a class. If anyone wants us to try it out with you in September, just let us know.

Set-up for the dig with bits and pieces from around the house

Archaeologists don’t know what they’re going to find but if they dig carefully they can find and record even the minutest traces of past human activity, like footprints preserved in clay. When kids dig, they’re not being careful being they don’t have the experience of looking for things. To give them that experience in our minidig we tried building the excavation with them first and then digging it out again. It gives them clues of what to look for. In a class of thirty 7 year olds, you could get each half of the class to create a dig and then swap digs so children still get the sense of discovery, but have some idea of the things they might be looking for.

It helps if children have some idea of the timeline of prehistory and particularly how houses change over time before you start. We started out with a plastic box and some clay, which was spread on the bottom as the ‘natural’. ‘Natural’ is technically a layer below which there is no human activity, but sometimes this doesn’t work in practice. Let’s ignore that for the moment.

Children can built an early house, maybe choose a Mesolithic tipi shaped house, or a Neolithic stone built house like at Skara Brae on this layer. We let the 4 year olds leave footprints with play figures, and you can gauge whether your older kids would still like to do that. The figures are also useful because they can accidentally drop objects that get embedded in the clay layer, in this case a replica bone flute, a shell and a flint core.

Discuss out of those things, which would still be around in 10,000 years time for archaeologists to find. If it rots, take it out.We took out the tipi, leaving post-holes behind to look for later.

We covered this up with sand and built a Neolithic stone rectangular structure (out of Lego) above. Artefacts left by the Neolithic inhabitants included some antler, a flint tool and, new for the Neolithic, a sherd of pottery.

When covered with wind-blown sand it left quite a lump. The hollows around were filled in with gravel from a meandering river.

On top of this gravel layer a roundhouse was built. Roundhouses were in use during the Bronze Age and Iron Age. If you want to make sure it’s Iron Age and not earlier, throw some iron in there. Once again we discussed whether the house would stay. As it was built of wood, mud and straw we decided it had to go, again leaving post-holes behind.

We finally covered the whole thing up with compost, pretending to be topsoil. As topsoil is generally a mixed layer, because of ploughing or just worm action, we had objects dating from the Roman period to today in that layer. Obviously, sometimes these periods are represented by sealed layers that haven’t been touched by the plough. Each of the previous periods would have had its topsoil, so as a variation you could put a thin layer of compost over each successive layer.

A green towel served as the grass and then the children were allowed to deturf and start digging. Digging is not the best word for it, though, as archaeologists usually use pointing trowels, not garden trowels, and employ a brushing motion, rather than digging. As we were working with 4 year olds, we decided it would be safer to use brushes. Any soil that was disturbed by the brush was scooped out. Any artefacts were put in a tray to look at later. The diggers soon noticed when they got down to gravel – it felt different to brush, it looked different and it even sounded different. We removed the last of the topsoil and had a look at the gravel layer.

Unfortunately we couldn’t see the post-holes of this layer as the gravel had been slightly disturbed, but that’s why archaeologists have to dig so carefully! When digging through the gravel, we put our finds in a separate tray. We soon found the sand, which looked, felt and sounded different again, and stopped to clean up the top of that layer. Soon we exposed the house and dug up the finds in the sand, which were put into a third tray. Coming down onto clay was another change and we cleaned up that surface to see whether we could see the post-holes. We could, faintly, and if a thin layer of compost had been put on top of the clay to start with, before the sand, they would have shown up beautifully. If the clay layer at the bottom had been smoothed out before building on, that would have helped too.

After cleaning up each layer, children should draw their dig, especially any post-holes or walls they have found. Older children could extend their learning by digging down through the layers to make a ditch around a house. The challenge for the other group would be to work out which layer that ditch was dug from.

After the dig is finished, go through each tray of finds to examine what came out of each layer. What was in the lowest layer? Is that the earliest or the latest layer? What is missing from that layer? Can children hazard to decide which time period it might have been?

Digging in this way gets across four main points:

• Archaeological excavation is more than just digging for artefacts
• That it matters about where on a site the artefacts were found
• How layers built up on a site and how archaeologists recognise, investigate and record them
• How artefacts can help work out both relative dating and what was happening in each layer

This session will be written up for the Hamilton Trust and the full instructions will be available from them, along with a whole block of lessons, so do get your school to subscribe to their service if they haven’t already.