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25 Cards in this Set
- Front
- Back
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What is the melting point of water? |
32 degrees F |
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What is the boiling point of water? |
212 degrees F |
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Most substances ____ when heated and ____, or get smaller, when they become colder. |
expand; contract |
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What is the temperature at which liquid water changes to a solid and what is it called? |
32 degrees F; freezing point of water |
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What is the ability to do work? |
energy |
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Scientists say that ____ is done when an object is ____. |
work; moved |
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What is a push or a pull on an object? |
force |
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What is the force which draws things down toward the center of the earth? |
gravity |
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In order for you to lift something, you must exert more ____ than ____ does on that object. |
force; gravity |
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If a box weighs 15 pounds and you exert 14 pounds of force, will you be able to lift the box? |
No |
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If a box weighs 14 pounds and you exert 15 pounds of force, will you be able to lift the box? |
Yes |
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Some objects which are not moving have the potential of moving; they have ____ stored in them. |
energy |
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What kind of energy is stored in objects which are not moving? |
potential energy |
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When water is heated, what happens to its molecules? |
they increase in speed and spread farther apart |
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One quart of water can produce how many quarts of steam? |
1,700 quarts of steam |
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About 21% of air is ____. |
oxygen |
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Oxygen is ____% of air. |
21% |
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Air is about ____% nitrogen. |
78% |
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Air is about 78% ____. |
nitrogen |
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What percentage of air is carbon dioxide? |
1% |
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1% of our air is ____ ____. |
carbon dioxide |
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How many miles does the atmosphere go up above the earth? |
1,000 miles |
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What holds the atmosphere in its place and keeps air from floating off into outer space? |
earth's gravity |
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Because of the force of gravity, which portion of the air is the densest? |
the air closest to the earth |
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Although most of the earth's air is in the atmosphere, some air is mixed in the ____ ____. |
earth's soil |
