Science activity
Fossil Dig Excavation
Be a paleontologist! Dig for hidden treasures buried in sand or playdough. Find toy dinosaurs and shells and brush them clean like a real scientist!
Materials and setup
- plaster of Paris
- sand or rice
- small toys and shells
- paintbrush
- wooden sticks
- spoon
- clay or playdough
- paper cups
- shallow box
- markers
- paper
How this changes by age
Pre-K (ages 3–4)
Be a paleontologist! Dig for hidden treasures buried in sand or playdough. Find toy dinosaurs and shells and brush them clean like a real scientist!
Steps
- Bury toy dinosaurs, shells, and plastic bones in a bin of sand or rice.
- Give your child a paintbrush and small spoon as excavation tools.
- Dig carefully and brush away sand to uncover each hidden object.
- When you find something, examine it: 'What do you think this is? Is it a bone or a shell?'
- Talk about paleontologists: 'Scientists dig up old bones and shells to learn about animals that lived long, long ago!'
- Tell a grown-up one thing that surprised you.
Learning objectives
- Understand that paleontologists dig for and study ancient remains
- Practice careful excavation techniques using tools
- Identify and describe objects found during excavation
Kindergarten (ages 5–6)
Make your own fossils by pressing objects into plaster, then excavate them from hardened plaster blocks. Learn what fossils tell us about ancient life.
Steps
- Make fossil imprints: press shells, leaves, plastic dinosaurs, and toy bones into a layer of clay or playdough to make impressions. Remove the objects.
- Mix plaster of Paris according to package directions and pour over the clay impressions. Let it dry overnight.
- The next day, peel away the clay to reveal your fossil casts!
- Now make excavation blocks: bury small toys in fresh plaster in paper cups. Let them harden.
- Use a paintbrush, wooden stick, and spoon to carefully excavate the objects from the plaster.
- Create a 'museum display' of your fossils with labels describing each one.
- Tell a grown-up one thing that surprised you.
Learning objectives
- Create fossil molds and casts using plaster
- Practice careful excavation techniques on hardened material
- Understand that fossils are records of ancient living things
Early elementary (ages 6–8)
Study paleontology by creating, excavating, and analyzing fossils. Learn about fossil types, geologic time, and what fossils reveal about ancient environments.
Steps
- Research fossil types: body fossils (bones, shells), trace fossils (footprints, burrows), mold fossils (imprint), and cast fossils (filled imprint). Find an example of each.
- Create a layered excavation site: in a shallow box, pour alternating layers of colored plaster with buried objects at different levels. Let each layer dry before adding the next.
- Excavate your site layer by layer, just like real paleontologists. Record what you find at each level, noting the layer color and depth.
- Research: fossils in deeper layers are older. This is the Law of Superposition. Explain how scientists use this to determine relative age.
- Choose a famous fossil discovery (T-Rex 'Sue,' Lucy the Australopithecus, or a local fossil site). Research when it was found and what scientists learned from it.
- Create a geologic timeline poster showing major eras and the types of life that existed in each.
- In one sentence, tell a parent or sibling what surprised you today.
Learning objectives
- Distinguish between body fossils, trace fossils, molds, and casts
- Apply the Law of Superposition to determine relative age of fossil layers
- Connect fossil evidence to ancient environments and geologic time
Upper elementary (ages 8–10)
Conduct a full paleontology investigation: create a multi-layered dig site, practice scientific excavation methods, analyze fossil evidence to reconstruct ancient ecosystems, and write a paleontology research paper.
Steps
- Create a complex excavation site in a large container: pour 5-6 alternating layers (use different colors of plaster mixed with sand or coffee grounds). Embed different objects in each layer to represent different time periods.
- Excavate scientifically: create a grid system over your site. Excavate one grid square at a time. For each find, record: grid location, layer number, depth, description, and sketch.
- Research how real paleontologists date fossils: relative dating (stratigraphy, index fossils) vs. absolute dating (radiocarbon dating, potassium-argon dating). Explain each method.
- Analyze your 'fossil' assemblage: based on which objects were found in which layers, tell the story of how the environment changed over time.
- Research a major extinction event (end-Permian or end-Cretaceous). What fossil evidence reveals that these events happened? How do scientists know?
- Write a paleontology research paper: describe your excavation methods, present your findings with the grid data, analyze what your fossil layers reveal, and connect to real paleontology concepts and methods.
- In one sentence, tell a parent or sibling what surprised you today.
Learning objectives
- Apply scientific excavation methods including grid systems and stratigraphic recording
- Compare and evaluate relative and absolute dating methods
- Analyze fossil assemblages to reconstruct ancient environments and interpret change over time
Safety and evidence note
Read the full activity before beginning. An adult should supervise tools, heat, food, outdoor work, movement, and experiments as appropriate. Completion records that the activity was done; the child’s explanation, work sample, photo, or demonstration is stronger evidence of learning than a completion check alone.
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