66953_Prof CHEM INS_Cover(6L) - Imaginarium

DENSITIES BY ADDING SOLID OBJECTS
Let's add a third element to the mix: syrup. You can compare densities by adding solid objects:
• Syrup
• Cooking oil
• A glass tumbler
• Water
• Several small objects
Carefully pour the syrup into the tumbler and fill it to one quarter of its volume. Slowly pour the same amount of
oil into the tumbler and, lastly, add the same amount of water. The three liquids will not mix but rather form 3
distinct layers.
If you add objects, you can see how each floats in a different layer. It all depends on density: the weight of a
substance given a certain volume.
Liquids can float or sink like solid objects. A lower density substance weighs less than a higher density one with
the same volume. An object or a liquid will only float in a more dense liquid.
FROZEN WATER
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You can test the density of frozen water. To do this, you will need the following
material:
• The mini laboratory
• Water
• Salt
• A measuring spoon
water test tube
salt test tube
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Fill both test tubes in the mini laboratory with water. Using the measuring spoon,
place a large measure of salt into one of the test tubes and put it in the freezer.
Check it every 10 minutes. Which tube freezes first? The one with water or the one
with the salt solution?
What happens if we mix water and sugar?
To answer this question with an experiment, you will need the following material:
• The mini laboratory
• Lukewarm tap water
• Sugar
• A measuring spoon
• A beaker
• A funnel
Place the funnel on one of the test tubes and pour lukewarm tap water until it
reaches the number 4 mark. Place 5 large measures of sugar into the funnel with
the measuring spoon so it goes into the water. Close the tube and shake well to
dissolve the sugar.
Once the water has settled, look at the volume scale next to the test tube. How
much sugar water is there? It still reaches number 4. When the sugar dissolves in
the water, its molecules fill the tiny spaces between the water molecules, so sugar
dissolved in water does not increase the volume of water in the test tube. What
happens if you put it in the freezer? Which freezes faster, salt water or sugar water?
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