Learning Targets : Where's the Air?
• Air has matter. It can take up space, has mass and can be compressed
• The atmosphere is the layers of gases surrounding Earth
• The troposphere is a mixture of nitrogen, oxygen and other gases including water vapor.
1.1 Air has matter. It can take up space, has mass and can be compressed.
When air is compressed the number of air molecules does not change. What happens is the molecules have less space to move around in.
Imagine taking all of the students in your class and moving them into the back room (where the kitchen is). The number of students hasn't changed - rather they have been compressed into a smaller space. Two ballons with equal amounts of air are balanced. The air from the white ballon is released leaving the black balloon filled with air. The balance drops to the side of the black balloon as it weighs more. The air inside of the black balloon has mass. TRY IT! Get a ballon. Using a digital scale, weigh the mass of the balloon. Fill the balloon with air and weigh again. What were your results? Explain? |
1.2 The atmosphere is composed of layers of gases surrounding Earth.
Layers of the Atmosphere
Troposhere - The troposphere is where all weather occurs. The base of this layer is warmer than its top because the air is heated by the surface of the Earth, which absorbs the Sun’s energy. Stratosphere - Above the troposphere lies the stratosphere where jet airplanes fly. Temperatures increase with altitude because of increasing amounts of ozone. The ozone layer absorbs harmful ultraviolet rays of sunlight. Stratosphere - As the mesosphere extends upward above the stratosphere, temperatures decrease. The coldest parts of our atmosphere are located in this layer and can reach –90°C. Thermosphere - In the thermosphere, the air is thin, meaning that there are far fewer air molecules. The thermosphere is very sensitive to solar activity and can heat up to 1,500°C or higher. |
1.3 The troposphere is a mixture of nitrogen, oxygen and other gases including water vapor.
The troposhere is when all life exists. The troposhere is made up of gases, with nitrogen and oxygen being the most common gases. Water vapor is also part of the troposhere. THINK: We learned earlier in the year that all living things need to exchange gases. What is it about the gases in the troposhere that allow life to exist? Share your ideas with a member of your science team. |