Week 4 - Density and Buoyancy
Changing Density
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Lesson 14: Changing Density
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Background Information
Density and Temperature Can the density of an object change? To answer a question with a question, does ice float? Of course ice floats and therefore it must be less dense then liquid water yet they both are made from water. Therefore the density of water changes with temperature.
As a general rule (ice is an exception) warmer substances are less dense. As you know, when substances are heated, the molecules move more rapidly. As the molecules move more rapidly, they take up more space. Less molecules in a given area means lower density.
Density and Concentration The relationship between density and concentration is simple: The more solute (i.e. salt or sugar) the more dense.
It is very difficult to swim in the dead sea of Israel because there is a large concentration of salt in the water, therefore the water is more dense then man and man floats on the surface of the water.
Density and Temperature Can the density of an object change? To answer a question with a question, does ice float? Of course ice floats and therefore it must be less dense then liquid water yet they both are made from water. Therefore the density of water changes with temperature.
As a general rule (ice is an exception) warmer substances are less dense. As you know, when substances are heated, the molecules move more rapidly. As the molecules move more rapidly, they take up more space. Less molecules in a given area means lower density.
Density and Concentration The relationship between density and concentration is simple: The more solute (i.e. salt or sugar) the more dense.
It is very difficult to swim in the dead sea of Israel because there is a large concentration of salt in the water, therefore the water is more dense then man and man floats on the surface of the water.
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Exercise 4.2: Float an Egg|
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Self-Assessment: Density Review
 Review Links:Try the following online density review quizzes. |
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