As part of their Geology studies, Prep III has been looking at how fossils are formed. They have learned that fossils are formed in sedimentary rocks when animal and plant remains are buried under layers of mud. Over time the soft parts rot away leaving hard tissues such as bone which either leave an impression, or are actually turned into rock by mineralization. Millions of years later, the fossils weather out of the rock layers and are found by paleontologists.

We decided we could not wait that long, so we accelerated the process by making casts of dinosaur models. Having pushed our dinosaur of choice deep into playdough-filled foil tray to make a mould, we mixed plaster of paris to the consistency of yoghurt, poured it carefully into the dinosaur-shaped depression and gently shook the tray to “puddle” the liquid plaster deep into the mould.

Forty eight hours later, when the plaster was well and truly set, we carefully peeled the playdough from the plaster plaque to reveal….. a perfect dinosaur fossil!

Making Fossils with Prep III

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