Fossils - how to make them when you can't find them

James loves dinosaurs. He loves digging. Imagine his delight when he discovered that there are real jobs that involve both of his passions. His current ambition is to be an archaeologist when he isn't in space. We have been reading a lot of books about archaeology recently and James asked me to take him somewhere so he could find his own dinosaurs. I was slightly dismayed since the only place I could think of nearby is heritage listed - meaning we are not allowed to dig or remove the fossils there. 

Since we couldn't dig real fossils up, I thought digging up some pretend fossils would be the next best thing.

We took some clay and put it in the bottom of a plastic container. We tried to keep the surface of the clay as smooth and even as possible.

Okay, so the surface isn't as even as it could be. My three helpers were having a little too much fun poking the clay and making holes before they patched them up again. Next we found some plastic dinosaurs to press in to make the indent we will cast our fossils from. We pressed them in more than halfway so ensure there was plenty of space to pour the plaster in to.

We then made the plaster mix and poured it in to the container on top of the clay. Since I have recently had a few disasters making plaster mixes, I thought I would share that it is usually a 2:1 ratio of powdered plaster to water and it is best to add the water gradually in case you don't need all the water.

 We left the plaster for a few hours to set. Once it was hard to touch we tipped the entire block out of the container and peeled the clay away from the plaster. The clay is still good to use so we wrapped it tightly in cling wrap and put it away in the cupboard for another day.

Here is one of the fossils we made. 

I think next time I would like to try making animal tracks or a collection of footprints.

Tomorrow when the plaster is fully dry we will bury it in the sandpit and leave James to dig them up again.