Science Experiment: Create-A-Fossil Investigation

Create-A-Fossil Investigation

Fossils are remains of life from the past preserved in rock. The most common types of fossils are molds and casts. This activity will give you the chance to make modern-day molds and casts.

A mold forms when something is pressed into soft mud and removed by decomposition or pulled out, leaving an impression of the object. A cast is a three-dimensional (3-D) example of an object of the past created when a mold fills up with sediments like mud, sand, or volcanic ash.

You will need: fine sand, 2 containers (one for the molds/casts, one to mix plaster), quick-set Plaster of Paris, and various items to create molds/casts

  1. Fill 2/3 of your container with moistened sand.
  2. Press found objects into the moist sand – Leaves, plastic dinosaurs or bugs, shells, and twigs; other items with interesting textures work well.
  3. With the help of an adult, mix Plaster of Paris and carefully pour into the impressions in the sand.
  4. Wait patiently for the plaster to dry to the touch, about 30-40 minutes. Then turn the container out onto a flat work surface, remove the excess sand, and let the remaining plaster dry. Finally, whisk away dried sand using a small brush and uncover your creation!

What is a fossil?

Fossils are remains of life from the past preserved in rock. The most common types of fossils are mold and casts. A mold forms when something is pressed into soft mud and removed by decomposition or pulled out, leaving an impression of the object. A cast is a three-dimensional (3-D) example of an object of the past created when a mold fills up with sediments like mud, sand, or volcanic ash.