What is in the Classroom Pack?
Supplies so you can prepare 10 hands, 2 at a time
10 Vacuum valves
2 Vacuum pumps
12 Latex gloves
1 Instruction sheet
1 cup of seeds, beans, polenta, raw sugar or sand per hand
Your lab latex gloves may also do the job. Vinyl or nitrile gloves cannot be used as they do not contract well.
Suggested Classroom Activities
1. Determine if air has mass
Use a sensitive electronic balance (~0.01g) to determine the mass of the extracted air. The glove is weighed before and after air is extracted.
When the glove gets filled with 1 cup of “whole wheat” the density is such that it just floats in water. Extracting the air, makes it sink.
3. Is it really the outside air that locks the sand in?
Extract air from the glove, extend the fingers, and place it inside a vacuum container. See photo. Evacuate the air from the container and keep your eyes on the glove . . . Then let the air flow back into the container.
The best filler to use
The following two products,
Polenta (coarse) and
perform very well in this demonstration. Do not mix them, use each on its own. They have the right consistency and particle size distribution that enhance the feel. Try to locate them and use them instead of sand. You’ll need at least 1 cup.
Create a weird skin effect
Fill the gloves with any of these fillers to create a peculiar skin effect. We have used the following coarse fillers with great success. What have you got in the pantry? Tip: Do not use fine products where small particles can sneak through the fabric and block the valve. Cornflour and castor sugar are definitely too fine.
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