Make an Imprint Fossil
In this science activity, kids will make an imprint fossil.
Fossils are preserved imprints or traces of plants and animals. For example, imprints of plants or footprints from long ago are sometimes found preserved in rocks. You might also find fossilized things like bones, teeth, wood, and even droppings (coprolites). Many of these fossils are formed when an animal or plant dies and is covered by layers of mud that, over time, turn to rock. This is why we find most fossils in sedimentary rock. In the case of bones, teeth, wood and droppings, minerals from the mud and soil slowly replace the organic matter in these things to create something that is mineralized and hard like rock. In the case of petrified wood, when a tree dies in a wet area, water fills the small holes in the wood and deposits minerals that harden, turning the wood to rock.
An imprint fossil is the outline of a plant or animal that has been left behind in a rock.
Scientists who study fossils are called "paleontologists."
- Plaster of Paris - 1/4 cup per student
- Water - 1 tablespoon per student
- Disposable cup - 1 per student
- Plastic spoon, popsicle stick or similar - 1 per student
- Artificial plant leaves - 1 per student
- Small Petri dishes, lids or similar - 2 per student
Place ¼ cup plaster of Paris into a disposable cup. Add 1 Tablespoon water to the cup and stir until the plaster resembles thick frosting. Add an additional teaspoon of water as needed to achieve the correct consistency.
Scoop out the plaster into the bottom of the Petri dish or lid. Gently tap the container on the table to allow the plaster to evenly spread out.
Gently press an artificial plant leaf into the plaster, being careful not to submerge it. Use your spoon or popsicle stick to tap it into place. Put this aside to harden for about 30 minutes, then gently peel off your leaf. You will be left with an imprint fossil!
If a number of fossils are made, you can make a game of trying to match the imprint fossil to the object that made it.
For younger children, you can also do this activity with craft dough and a hard object, such as a shell or small toy dinosaur.