Hold That Pose!
Halloween masks are one-size fits-all. But those marvelous masks that create those real-looking make-believe faces on film are custom-made. How does Jim Carrey become The Mask or Robin Williams become Mrs. Doubtfire? It all begins with molds. What do mold makers know about materials? Explore what happens when a plaster mold is made. Is what you notice a special effect, too, or science in a starring role?
You will need: plaster of Paris (found at a drugstore or hardware store), a pitcher of water, measuring spoons, sealable sandwich bags, a ballpoint pen, a clock or timer, and a small paper plate. If a thermometer is available, it will improve your investigations.
Measure out 2 tablespoons of plaster of Paris powder into each bag. Measure 1 spoonful of water into the first bag. Seal and label with "1 part water, 2 parts plaster of Paris." Add 2 tablespoonfuls of water to the second bag and 3 to the third, labeling each.
Squish the bags around to completely mix. Then make some key observations. Every two minutes check each bag. What can you observe about the contents inside?
What do you notice about the temperature? Use a thermometer, if you have one, for an accurate measure, or judge the temperature with your hands. What would you expect to feel if you set your hand in plaster of Paris to create a mold of your hand?
Which of your three samples would you use to create a mold? Use the recipe you think worked best. Pour the mixture onto the paper plate and create a cast of your handprint or of some other object.