1. Topic-
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Understanding Density and Solubility |
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2. Content-
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Density: the amt. of stuff in a certain amount of space.
(i. e. the more stuff in a space the less dense).
Solubility: when one substance is mixed with another substance.
(i. e. water/salt)
Solute: the thing you are adding.
(i. e. water)
Solvent: the thing you are adding to it.
(i. e. salt) |
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3. Goals: Aims/Outcomes-
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1. Define Density and Solubility
2. Explain why some things float
3. Show how an object can both sink and float depending on its density |
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4. Objectives-
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1. Explain Density
2. Explain Solubility
3. Demonstrate how one slice of a potato sinks, floats, and stays in
the middle of the glass |
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5. Materials and Aids-
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*Cups
*Water
*Potato slices/cubes between 3/4" and 1" thick/smaller in diameter
than the cups
*3 Glasses
*Stirring spoon
*Pickling Salt |
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6. Procedures/Methods-
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A. Introduction-
1. Ask why some things float.
2. Explain Density.
If something is less dense than a liquid, it will float on the liquid.
If something is more dense than a liquid, it will sink. An object
can both sink and float depending on how dense it is compared to the
liquid around it.
3. Explain Solubility.
When you mix a substance into another substance, like salt into water,
how well the two mix is call solubility. If I put marbles in a glass
of water, will you still be able to see the marbles? Yes, they will
look exactly the same. They are not soluble in water. What if I put
salt into water? Is salt soluble in water? (If asked the thing I am
adding is called the solute or water, and the thing I am adding it
to is called the solvent or salt). |
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B. Development-
1. In one cup, mix salt and water, trying not to over saturate it.
It's better if it's not cloudy.
2. In one cup, have just plain water.
3. In another cup, have salt water on the bottom half, then put plain
water on top of that. Use a spoon to prevent the water from pouring
directly into the cup so that the salt water and regular water does
not mix. Also pour plain water down side of cup slowly.
4. Place a piece of potato in the first cup. The potato should float.
5. Place a piece of potato in the second cup. The potato should sink.
6. Place a piece of potato in the third cup. The potato should sink
to the middle, where the plain and salty water meet. Discuss the fact
that it is possible for liquids to float on top of each other, and
that the potato is actually floating on the salt water and sinking
below the plain water. |
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C. Practice-
1. Students to re-create the experiment by mixing their own solvents
and adding their potato's. |
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D. Independent Practice-
Find items at home and see what floats and what sink. On a sheet
of paper write down which are less or more dense. |
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E. Accommodations (Differentiated Instruction)-
1. Pre-cut potato's
2. Solution premixed
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F. Checking for understanding-
1. Quiz
2. Discussion
3. Reflection Paper |
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G. Closure-
1. Re-define Density
2. Re-define Solubility
3. Discuss the fact that it is possible for liquids to float on top
of each other. |
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7. Evaluation-
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1. Observe students mixing the solvents
2. Observe students following numbered step process. |
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