(4) Plaster of Paris Explanation: Plaster of Paris is a plaster made by calcining gypsum. It can be used to impregnate gauze bandages to make a sculpting material called modroc. It is used similarly to clay, as it is easily shaped when wet, yet sets into a resilient and lightweight structure. This is the material which was (and sometimes still is) used to make classic plaster orthopedic casts to protect limbs with broken bones.