Two Ways to Make Play Fossils

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I remember growing up in Colorado and finding all kinds of fish fossils in the mountains (so cool!). BUT I haven’t found many fossils in my adult years and sadly I didn’t keep any of my childhood finds. So I decided to make our own play fossils to use in our fossil dig sensory bin.  

We have been really loving sensory play in our house lately! And with it being National Dino Day, I figured we needed to add a prehistoric touch to our sensory bin!  

Here are two ways we made our own play fossils!

Method #1: Plaster Fossils

I learned this method in Classical Conversations during our hands on science class. We used Janice VanCleave’s 201 Awesome, Magical, Bizarre, & Incredible Experiments (It’s a mouthful, I know!). This is my own version of the experiment you can find in this book. It’s a great way to have some fun and also learn about how real fossils are made!

Supplies you’ll need:

– Play dough or clay

– vaseline or cooking spray

– toys/shells

Plaster of Paris

– water

You’ll also want a small dish to mix the plaster and you may also want a file or piece of sandpaper if you want to round the edges of your fossil.

Instructions: first, make a ball with the Play dough or clay and slightly flatten it. Apply a little vaseline or cooking spray on your selected toy or shell. This is simply to allow for easy removal of the item from the dough. Press the item into the dough. Now remove it to reveal the impression.

Now it’s time to mix the plaster! Carefully follow the instructions on your plaster. 

Note: While plaster of paris is non-toxic, it’s important not to breathe in the powder, so mix gently. 

Typically you will mix 2 parts plaster to 1 part water. I used 4 tbsp of plaster powder and 2 tbsp of water to make 4 small fossils.

Next, simply pour the plaster into your molds and let sit at least 45 minutes before removing from the dough. I let mine sit 1 hour just to be sure! BUT the fossils will still be damp. The plaster should be allowed to dry for a day or so. I like to get them out of the molds and clean them up a bit before they are perfectly set though.

You may find a bit of dough is stuck to your fossils. Simply take a toothpick or something similar and scrap it off. It will come off pretty easily. I also like to break off any thin excess plaster around the perimeter of the fossil and shape it a bit with a nail file or sand paper.

And that’s it! You’re done! 

Add these to a sensory bin or a fun fossil unit study!

Method #2: Salt Dough Fossils

This is a super easy method and the kiddos can get involved too!

Supplies you’ll need:

– flour

– salt

– water

– toys/shells

– baking sheet

(Pardon my very used baking sheet! It has seen a lot in its lifetime!)

Step one is to mix up your dough! I have used several different recipes before, but for this project I didn’t want a huge batch. 1 cup of flour, 1/4 cup of salt, and about 1/2 cup of water did the trick! You may need to adjust the water to get your consistency right. 

Next, roll out a little dough. I left mine a bit thick so I could really press the toys into the dough and get a nice deep impression. Use a butter knife to trim off the excess and then shape the edges with your fingers. 

Transfer all of your fossils to your baking sheet. Dry them out in the oven at 275 degrees F for about 2 hours. 

Easy peasy lemon squeezy! Salt dough fossils! 

And there you have it! Two ways to make your own play fossils. They are so much fun and add a sensory element to unit studies. I wish you luck on your fossil making adventures!