I first saw this project here, and it fit in perfectly with our study of fossils, and adds perfectly to our fossil model collection. Most sedimentary rock forms under water. Sediment, or pebbles, sand, clay and plankton (bodies of tiny dead animals and plants), is slowly buried by more sediment piling on top. Over a long period of time, as the pile gets heavier and heavier, the particles near the bottom are squeezed closer and closer together. Groundwater brings new minerals that cement the particles together to form sedimentary rock. If the sediment is mainly sand, it will change into sandstone. If the sediment is mostly clay, it will form shale. If the sediment contains mainly plankton, it will turn into limestone.
To simulate but speed up this process we infused some sand with the minerals (Epsom Salt) to cement the particles of sand together. To show how dinosaur footprints are sometimes left in rock, we pressed a toy dinosaur's foot into the wet sand to make an imprint. We will let this dry out over the weekend (or perhaps longer) and hopefully, we will have a model of sandstone with a dinosaur footprint in it.