s8pe-205ci-ca
11/28/05
12:08 PM
MAZER
Page 156
CHAPTER INVESTIGATION
Chemical and Physical Changes
OVERVIEW AND PURPOSE Changes happen around you
every day. You might observe an egg boiling in water, a sheet of
paper ripping, or rust forming on the handlebars of your bike.
Some of these changes are physical changes, while others are
chemical changes. The difference between physical and chemical
changes is not always easy to notice. Cotton candy, for example,
is simply sugar melted and spun. In this investigation you will
• observe several common changes taking place
• identify physical and chemical changes
Procedure
Make a data table like the one shown on the sample
notebook page.
Place an ice cube in a plastic cup and let it sit for 10 minutes.
Record your observations.
MATERIALS
• ice cube
• 3 plastic cups
• metal spoon
• sugar cube
• granular sugar
• 2 test tubes
• wooden matches
• candle
• test-tube holder
• test-tube rack
• 2 50 mL beakers
• water
• vinegar
• baking soda
8.5.c, 8.9.b
156 Unit 2: The Structure of Matter
Use the metal spoon to grind a sugar cube into a fine powder.
Record how the sugar has changed.
Pour a half spoonful of the granular sugar into a test tube. Light
the candle and hold the test tube with the holder so the bottom
of the test tube is just above the flame for several minutes. Be
sure the top of the test tube is pointed away from you. Place the
hot test tube in the test-tube rack when done. Record your
observations.
Pour 50 mL of water into a plastic cup and add 50 mL of vinegar.
Record your observations.
Pour 50 mL of vinegar into a plastic cup. Add a spoonful of
baking soda powder. Record your observations.
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