Salt Dough - 1 cup salt, 1 cup plain flour, up to 1/2 cup of water. Mix together and knead until smooth and stretchy. Add more flour if too sticky and more water if too crumbly. For a footprint 3 hours @ 100 degrees C or 200 F. Cool for 2 hours for smaller things, e.g. Xmas decorations or letters
This is a great website with tons of science experiments. Some are quick and some are more complicated. Introduce "What scientists do" through the experiments and it really grabs the students in. They can't quit asking....When are we doing another science experiment?