Activity
Casting and Molding
Students who are blind or visually impaired replicate casting and molding techniques used in industry.
Purpose:
To provide the opportunity for students who are blind or visually impaired 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.
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
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.
Procedure
- Place gelatin into bowl or other container.
- Pre-measure water when cold.
- Heat water to boiling. (see background information for adaptive technique); then add the boiling water to the gelatin.
- Stir well until the gelatin is completely dissolved.
- Allow gelatin mixture to cool.
- Set up funnel stand on tray.
- Under the opening of the funnel stand, place molds that have been sprayed with non-stick spray.
- Using a cup or a ladle to pour gelatin through the funnel into the molds.
- Refrigerate mold for several hours or overnight.
- 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.
NGSS Standards:
PS1.A: Structure and Properties of Matter
- Each pure substance has characteristic physical and chemical properties (for any bulk quantity under given conditions) that can be used to identify it. (MS-PS1-2),(MS-PS1-3)
- Solids may be formed from molecules, or they may be extended structures with repeating subunits (e.g., crystals). (MS-PS1-1)
- The changes of state that occur with variations in temperature or pressure can be described and predicted using these models of matter. (MS-PS1-4)
- ETS1.A: Defining and Delimiting Engineering ProblemsETS1.B: Developing Possible Solutions
- A solution needs to be tested, and then modified on the basis of the test results, in order to improve it. (MS-ETS1-4)
- There are systematic processes for evaluating solutions with respect to how well they meet the criteria and constraints of a problem. (MS-ETS1-2), (MS-ETS1-3)
- Sometimes parts of different solutions can be combined to create a solution that is better than any of its predecessors. (MS-ETS1-3)
- Models of all kinds are important for testing solutions. (MS-ETS1-4)
- Although one design may not perform the best across all tests, identifying the characteristics of the design that performed the best in each test can provide useful information for the redesign process—that is, some of those characteristics may be incorporated into the new design. (MS-ETS1-3)
- The iterative process of testing the most promising solutions and modifying what is proposed on the basis of the test results leads to greater refinement and ultimately to an optimal solution. (MS-ETS1-4)
By Kate Fraser
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