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Practicals

Making Fossils

Summary

Students make fossils of shells or plants.

Operation

This practical involves students making fossils from shells or plants using plaster of paris. The fossils can be painted when dry in order to accentuate the detail.

A selection of plant matter and/or shells will be required. Shells with rough edges or which have distinguished shapes work better than flat shapeless objects. Thick sturdy leaves or pine cones work well if fossils of plants are to be created. Small toy dinosaurs can be used for fun.

Equipment required (per set):

  • Plaster of paris
  • Disposable tub
  • Stirrer
  • Newspaper
  • Gloves
  • Selection of objects to be fossilised
The plaster of paris needs to be mixed to a smooth but fairly thick consistency in the disposable tub. The object then can be pressed into the surface of some plasticine to form a cast. The plaster of paris can then be poured into the cast and left to dry. Once the plaster had hardened, the object can be removed from the plasticine.

The plaster represents sediments that cover bodies and objects, building into a solid layer after many years. In nature, the object usually decomposes over time leaving an imprint of the surface in the sedimentary rock.

Once the plaster has dried, acrylic paints may be used to paint the fossil. Water based paints will soak into the plaster and will not give a good finish.

Safety

 Wear eye protectionWear eye protection.

Wear gloves.

The contents of this page are for information only. Please refer to CLEAPSS or ASE safety advice and/or publications before undertaking any preparation, practical experiment or using any equipment featured on this site or any other.