45 – 60 minutes

Fossils out of coffee grounds?!

That’s right! This activity shows you how to create your very own fossils using coffee grounds, cold coffee, salt, and flour.

Learning and Leadership
Image
Coffee ground fossil on baking tray.

How to Prepare:

Collect the following items before you begin:

  • 1 cup of used coffee grounds
  • 1/2 cup of cold coffee (for colour)
  • 1 cup of flour
  • 1/2 cup of salt
  • Wax paper
  • Mixing bowl
  • Starfish, seashells, small toy dinosaurs, or other small objects for the impressions
  • Cookie cutter, empty can, or a butter knife
  • Toothpicks and string to hang your fossil (optional)

Make your Fossil!

Step 1: Have an adult help you brew a small amount of coffee (you will only need ½ cup for this activity) and save the grounds. Allow time for the coffee to cool.

Step 2: Stir together the coffee grounds, coffee, flour, and salt in the mixing bowl until they are well mixed.

Step 3: Once mixed, knead the dough until it feels like it’s all the same texture and then flatten it out onto the wax paper.

💡Activity Hack! You can knead the dough by pushing it down in the middle and folding the sides over itself again and again, until it feels like it is all connected and not too sticky. 

Step 4: Use the empty can to cut out circles (or cookie cutters/butter knife for fun shapes!)

Step 5: Press your small objects firmly into the cut out dough shapes to leave an imprint. When you remove your object, you will see your fossil!

💡Activity Hack! You can use a toothpick to poke a small hole near the edge of the coffee ground fossils if you want to hang it later!

Step 6: Let your fossil dry and harden overnight. Depending on how thick you made them, it could take longer.

You can hang your coffee ground fossils the next day or use them in an archaeological dig.  Hide them in a sandbox or take them to the beach to hide and dig up with your friends!

Coffee Ground Fossils Complete! Congratulations!

How It Works

Fossils are ancient treasures that are millions of years old. They're the remains or traces of plants and animals that lived a  long time ago. 

How do fossils form? There are two ways fossils can form:

  1. Mineralization: The bones or even a leaf slowly soak up minerals from the ground. These minerals then turn the bones into rock over millions of years.
  2. Impression Fossils: Sometimes, instead of the actual thing, we find a print or impression left behind, like a dinosaur footprint. It’s like the earth taking a snapshot of the past!

This activity is inspired by:

https://craftsbyamanda.com/coffee-ground-fossils/