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Classroom activity:
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There are several ways to demonstrate or explore the concepts of heat and density. These include: |
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Feeling the heat:A. Light a candle and hold your hand about 5 inches from the side of the flame. Now move your hand about 5 inches above the flame. What do you notice? What is the explanation?
B. Repeat the demonstration for a more dramatic result by holding the head of a wooden match about ½ inch to the side of the flame for about ten seconds. (The match will not burst into flame.) Then move the match to the same distance above the flame. (The match will burst into flame.)
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Comparing the liquids:
Heat causes molecules of water to move more quickly. Therefore the food coloring is more quickly dispersed throughout the warmer liquid. |
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Marble molecules:
This represents molecules in a solid state - barely vibrating and taking up a minimal amount of space. Now add energy by shaking them a bit more, so that the molecules flow within the container. This represents molecules in a liquid state. They are moving more quickly and taking up a greater amount of space. Now add even more energy by shaking the container so that the marbles bounce off one another and out of the container. This represents a change to the gaseous state. The molecules are moving more rapidly and bounce off one another to take up greater space still. Discuss with students how this can be a model of changes in molecular density and movement as energy is added. Concepts:
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Additional demonstrations of density:
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