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Energy and Science Projects
For Students
Greenhouse Effect
Recreating the Greenhouse Effect
The Earth's climate has changed many times in the past. Subtropical
forests have spread from the south into more temperate (or milder, cooler
climates) areas. Millions of years later, ice sheets spread from the north
covering much of the northern United States, Europe and Asia with great
glaciers. Today, some scientists believe human beings are changing the climate.
How can that be? Over the past few centuries, people have been burning more
amounts of fuels such as wood, coal, oil, natural gas and gasoline. The
gases formed by the burning, such as carbon dioxide, are building up in
the atmosphere. They act like greenhouse glass. The result some experts
believe is the Earth heating up and undergoing global warming. How can you
show the greenhouse effect?
What You'll Need
Two identical glass jars
4 cups cold water
10 ice cubes
One clear plastic bag
Thermometer
What to Do
Take two identical glass jars each containing 2 cups of cold water.
Add 5 ice cubes to each jar.
Wrap one in a plastic bag (this is the greenhouse glass).
Leave both jars in the sun for one hour.
Measure the temperature of the water in each jar.
Which is warmer?
In bright sunshine, the air inside a greenhouse becomes warm. The greenhouse
glass lets in the sun's light energy and some of its heat energy. This heat
builds up inside the greenhouse. You just showed a small greenhouse effect.
What could happen if this greenhouse effect changed the Earth's climate?
Another version of a greenhouse is what happens inside an automobile parked
in the sun. The sun's light and heat gets into the vehicle and is trapped
inside, like the plastic bag around the jar. The temperature inside a car
can get over 120 degrees Fahrenheit (49 degrees Celsius).
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