Greenhouse Gases
In our last lesson we saw how the Greenhouse Effect heats up our atmosphere by reflecting infrared radiation back down to earth. In a greenhouse it is easy to see how it happens, the glass or plastic walls reflect the heat back into the house making it warmer. The atmosphere around the planet acts the same way, only it is harder to see because the walls are invisible! Instead of glass or plastic the 'walls' are made from Greenhouse Gases. There are many Greenhouse Gases however the most common are Water Vapour, Carbon Dioxide and Methane. Although we cannot see the gases they are always all around us and do are very good at reflecting infrared radiation.
We have already learned in past lessons how carbon dioxide levels in the atmosphere have recently risen a lot due to human activity. This rise means there are more Greenhouse Gas molecules in the atmosphere than before, bouncing more radiation back to earth. This causes the temperature of the earth to rise ... causing Global Warming!
The Greenhouse Gases
| Water Vapour (H2O) |
Carbon Dioxide (C02) |
Methane (CH4) |
|---|---|---|
 |
|
 |
NOTE: Hydrogen = White , Oxygen = Red and Carbon = Black
Activity
Now that we understand how the Greenhouse Effect and Greenhouse Gases work we are going to do an activity to see them in action! If you click HERE you will be taken to a Greenhouse Effect Simulator from the University of Colorado. Once you are at the new website click the button that says Run Now! After the program has started you will be able to adjust the levels of Greenhouse Gases as well as other factors to see the effect on it has on the earths temperature.
The Gathering Storm
This week's video from The Gathering Storm is called Mountain Drought. It can be viewed by clicking HERE. After you are finished go to the Discussion page to talk to other students about what you have seen!