Law enforcement agencies often make silicon gel molds to run ballistics tests designed to determine what happens when a bullet or knife hits a target. These molds allow a view of the path, trajectory and penetration of many different types of weapons. While your homemade silicon gel mold won't be used for formal forensic purposes, it can still be an instructive project to undertake. Just use gelatin powder and two quarts of water to create your own mold.
Measure out 8 oz. of gelatin powder mix using a measuring cup. Pour the gelatin powder into a large mixing bowl.
Pour 2 qt. of water into the mixing bowl containing the gelatin powder. Stir the mixture using a wooden spoon. Stir slowly and smoothly to ensure that you do not create air bubbles; bubbles will affect the mold once it hardens.
Place the mixture into the refrigerator for about two hours, or until it has cooled completely. The cooling process is known as "blooming."
Place the metal mixing bowl on top of a pot of boiling water in order to reheat the mixture. Use a thermometer to make sure that the temperature does not reach above 130 degrees Fahrenheit. Slowly stir the mixture as it heats up.
Spray a Tupperware container with a nonstick cooking spray to ensure that you can easily remove the mold from the container. Pour the silicone gel into the container and refrigerate for 36 hours.