Make a FOSSIL!

During our unit on the Earth (weathering, erosion, types of soil, and extinction and fossils), my class made "fossils." I love this culminating activity for the chapter and I've been doing it since I started teaching. It's super simple, and kids get to learn about the process of fossilization as they do the steps of the project. 

final result

So, the basic steps of fossilization are:

1) plant or animal dies and the soft parts rot away, leaving only the hard parts. A fossil can also be created through an imprint of a part of the animal like a footstep.

2) soil and mud cover the remains.

3) Over millions of years, all the soil, mud, and remains harden into a rock formation together.

4) weathering and erosion break away rocks and fossils can be uncovered. 

To demonstrate this in real life, I got Model Magic dough in white. I've only used this, so I'm not sure how well regular clay or even just plain play doh would work. I also bought Plaster of Paris. 

Each student gets a foam bowl. They get a ball of white dough that they press flat onto the bottom of the foam bowl. The dough should be pretty even all the way around. This dough and the foam plate represents the ground and the soil already on the ground.

Next, students get a small toy plastic animal. They push it down sideways into the dough, halfway, to leave an imprint..but not deep enough to break through to the other end of the dough. Take out the plastic animal. This represents the animal remains in the ground.

 Next, you make a mixture of equal parts Plaster of Paris and Water. This step has to be done quickly, because the mixture hardens pretty darn fast. Every year I basically throw out the container I make the mixture in since it is near impossible to get out the leftover hardened mixture, so it would be a good idea to just use Dollar store containers. 

I poured the Plaster of Paris mix into the bowls - enough to cover everything and make an even layer. The more even the dough is in the bowl, the more even the mixture will spread. This part represents more soil and sand covering the remains that are on the ground. 

Finally, the next day, which I told them is "a million years later," the mixture had dried. This represents the hardening of the soil and mud over the years to form a rock. Then through "weathering and erosion," we broke away the hard rock pieces, took off the dough from the bottom, and saw that the rock had a "fossil," of the animal in it. Basically, the liquid mixture had seeped into the imprint in the dough, so that when it dried, that part where the animal was, was raised higher than the solid around it after we took off the dough.

There you have it! Students remember how a fossil is formed and have a pretty neat souvenir from the experience. You can even have them paint it afterwards. 

To help teach them weathering and erosion, I used my mini unit Weathering, Erosion, and Rocks. You can check it out by clicking on the first picture!