Dino bones

Fossil making

Duration: 60 minutes

Resources:

• Fossil images
• A ball of clay
• A plastic cup containing a very small amount of plaster of Paris
• Sand
• Disposable gloves
• A selection of small objects that could be used to make “fossils” (for example, leaves, shells, dinosaur figures)
• A selection of excavation tools (for example, spoons, toothpicks, paintbrushes, toothbrushes, craft sticks)
• Safety goggles
• Dishwashing liquid (optional)

Key Learning:

This activity supports students’ understanding of fossil formation and paleontology, by getting students to create and excavate model fossils.

Safety note: This activity includes plaster of paris. Gloves and safety goggles must be worn at all times. If contact occurs, wash the skin immediately with warm water.

Activity preparation: Before the activity, you can prepare the plaster of paris by mixing 2 parts powder with 1 part water. Transfer very small quantities of the plaster of paris into individual pots for the students to use. Plaster of paris will set in around 20–30 minutes.

Activity instructions:

1. Explain to the class that they are going to create their own fossils and then excavate them as a paleontologist would.
2. Direct students’ attention to the Fossil images, and discuss what they know about dinosaurs, fossils and the process of fossilization. You can ask the following discussion questions:
   • How do we know what dinosaurs looked like?
   • What information can be gathered by looking at fossils?
   • How do fossils form?
   • Do all fossils form in the same way?
3. Organize students into pairs and give each pair the ball of clay, a container of plaster of paris, disposable gloves, safety glasses, and a selection of small objects that can be used to make fossils. Safety note: Remind students that they must wear gloves and safety goggles throughout the investigation.
4. Explain to students that fossils form when the remains or traces of living things become trapped or buried. Let them know that they are going to demonstrate this process now.
5. Ask pairs to shape the ball of clay into a disk. They should then select one of the small objects, press it into the clay, and then remove carefully to create a mold. Note: You can use a very small amount of dishwashing liquid on the outside of the object to stop it sticking to the clay.
6. Ask pairs to make small holes around the rest of the clay disk, as this will help the drying process later.
7. Ask pairs to carefully pour the plaster of Paris into the fossil mold, and then sprinkle a layer of sand on top. Safety note: Plaster of paris can get hotter as it solidifies, so the students must be careful not to touch it. Wash the skin immediately with water if contact does occur.
8. Once the plaster of paris has hardened, place the clay disks somewhere warm and leave to dry for a minimum of 24 hours.
9. Once the clay has dried completely, ask pairs to swap fossils with another pair.
10. Explain that paleontologists have to be very careful during excavation, as fossils are delicate. Give each pair a selection of excavation tools, and challenge them to excavate the fossil using the tools provided, without causing any damage. They should then try and identify the fossil. Note: Remind students to wear their safety goggles throughout excavation process.
11. Ask students to continue working like paleontologists and write a short report about how fossils are formed, the tools needed to excavate a fossil from rock, and what kind of clues a fossil can provide about the thing that made it.