Casting and Molding

Target subject: Technology/Engineering

Purpose

To replicate the process used to cast and mold molten metal, glass, and plastics, or liquid clay in industrial processes.

Background Information

Commercial gelatin prepared with a reduced amount of water creates a safe, easier to handle, substitute to replicate molten materials. The liquid takes on the shape of the mold as it hardens.

Preparation

If time is a factor the teacher can prepare the gelatin mixture in advance.  A recipe such as Jello Jigglers® creates a thicker liquid that forms firm castings. 

A convenient way to heat hot water for this experiment is to use a Hot Shot®. The pre-measured water is poured in to the top of the appliance; a button is pushed to begin the heating process; then the heated water is dispensed directly into the container.  This works well for students who lack the vision or hand skills to pour boiling water.

 Materials

• One 6 ounce box or two 3 ounce boxes of gelatin dessert powder
• Measuring cup
• 1.25 cups of boiling water
• A variety of molds either silicon or metal
• Tray
• Large spoon
• Hot plate or Hot Shot®
• Container for the gelatin and water to be mixed
• Funnel stand
• Ladle or cup with handle
• Non stick spray

Procedure

1. Place gelatin into bowl or other container
2. Pre-measure water when cold.
3. Heat water to boiling. (see background information for adaptive technique);  then add the boiling water to the gelatin.
4. Stir well until the gelatin is completely dissolved.
5. Allow gelatin mixture to cool.
6. Set up funnel stand on tray
7. Under the opening of the funnel stand, place molds that have been sprayed with non-stick spray.
8. Using a cup or a ladle to pour gelatin through the funnel into the molds.
9. Refrigerate mold for several hours or overnight.
10. Un-mold the shapes, the student can tactually explore the cast.

Please note: In a science lab, food items are regarded as chemicals and are not for consumption.