Plaster
Plaster of Paris, or simply plaster, is a type of building material based on calcium sulphate hemihydrate. Plaster is similar to motar or cement. Like those materials plaster starts as a dry powder that is mixed with water to form a paste which liberates heat and then hardens. Unlike motar and cement, plaster remains quite soft after drying, and can be easily manipulated with metal tools or even sandpaper.
Class Activity- Students began by cutting sheets of plaster into strips. Next students dipped the pieces of plaster in water and wrapped them around their fingers to make a mold. Students were then able to add extra features onto the mold, to make an animals, puppet, etc. This plaster finger mold activity would be especially suitable for primary grades as it is easy to follow.
Resources:
http://www.fresnofamily.com/activities/hands.htm
http://www.enchantedlearning.com/crafts/plaster/
http://www.kid-at-art.com/htdoc/lesson36.html
