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This Activity was inspired by the work of a high school student, Kara Bruce. In the summer of 1999,
she and Jerrold Jacobsen of the JCE staff created video sequences that illustrate the properties of
Magic Sand and compare its properties to those of ordinary sand.
There are five QuickTime movies that go with the Magic Sand activity. You will need to have
QuickTime 3 or higher installed to view the movies.
A free copy of QuickTime is available from Apple at
http://www.apple.com/quicktime.
In steps 1-3 of "Try This" on the student side of the Activity, students compare and contrast the
properties of Magic Sand and ordinary sand. The first two video sequences show these steps.
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The first sequence (MAGICSA1.MOV) shows the properties of Magic Sand. When it is dry, Magic Sand is free-flowing and cannot form a structure that holds its shape. When Magic Sand is poured into water, it has a silvery sheen and doesn't become wet. It can be molded into structures that hold their shape under water. When the water is poured off, the Magic Sand is dry.
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MAGICSA1.MOV is 716 KB.
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The second sequence (MAGICSA2.MOV) shows the properties of ordinary sand. When it is dry, ordinary sand is free-flowing and cannot form a structure that holds its shape. Ordinary sand becomes wet in water. It cannot be molded into structures that hold their shape under water. It remains wet when the water is poured off.
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MAGICSA2.MOV is 680 KB.
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The third video sequence contains a demonstration not performed by students during the Activity. A test tube is coated first with silicone grease and then Magic Sand. A thin layer of Magic Sand is sprinkled on the surface of the water. The test tube can be pushed into the layer of Magic Sand and below the level of the water. The sand on the surface of the water adheres to the sand on the test tube as the tube is pushed below the water surface. When the test tube is removed, the layer of sand falls off.
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MAGICSA3.MOV is 624 KB.
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In step 4 of "Try This" on the student side of the Activity, students test whether there is an upper limit to the number of water droplets that can be added to form a large water droplet on Magic Sand that is sprinkled on the surface of the water. The fourth and fifth video sequences show this step close-up.
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The fourth sequence shows that small water droplets do not soak through the sand layer, but stay in tight spheres on top of the sand.
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MAGICSA4.MOV is 788 KB. |
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The fifth sequence shows that if enough small water droplets are added to one large water droplet on the sand layer, the droplet eventually breaks through the layer. Consequently, the water droplet flows into the beaker.
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MAGICSA5.MOV is 428 KB.
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Citation
