Gases in Glasses (from Eco-Fun by David Suzuki & Kathy Vanderlinden)

Scientists believe that the Earth is getting warmer. One reason is that too much carbon dioxide, from factories and car exhaust, is building up in the atmosphere. This experiment shows how that heats things up.

What you need:

• 2 large glass jars that are the same size
• 2 pieces of dark paper or cloth
• 2 thermometers
• 1 jar lid
• A notebook and pen/pencil
• Oven mitts
  

What to do:

1. Lay the jars on their sides outdoors in the sun. Put a piece of paper or cloth inside each jar.

2. Place a thermometer in each jar on top of the dark paper or cloth. This will help you read the thermometers through the glass.

3. Put the lid on one of the jars. Turn the jars so that their tops face away from the sun. Then read the temperatures in both jars and write them down in your notebook.

4. Watch the jars. Record the air temperature every minute. When one thermometer gets close to the top of the scale, take the jars out of the sun and remove the lid. Otherwise, the thermometer could break.

5. Look at the air temperatures you’ve recorded. Which jar got hotter than the other? Why do you think it did? How much hotter did it get? How long did it take?

What’s Going On?
The jar with the lid on traps heat rays inside the jar. Light rays easily pass through the glass into the jar, but heat rays can’t easily pass through the glass and get out.

The layer of gases building up around the Earth acts much as glass does. The gases allow the light in but prevent the heat from leaving. Carbon dioxide is the main gas causing the problem. Trees could help remove the carbon dioxide from the air, but we’re cutting down too many forests.

Pollution from cars changes the Earth's climate and harms the air we breathe. Here are some activities to help you learn more about why the way we get around from place to place can be harmful to the environment.

Tips for making your neighborhood healthy
www.ns.ec.gc.ca/community/pdf/tips.pdf
(Acrobat Reader required - download here)

Try community mapping!
www.eya.ca/youthmappers/indexmain.htm
www.waytogo.icbc.bc.ca/framesets/toolkit/index_tool.html

Global warming crossword puzzle
www.epa.gov/globalwarming/kids/games/crossword/crossword.html