Chapter 10: Atmospheric Gases Input Page/Notes Chapter 10: At Atmospheric tmospheric Gases The atmosphere is a shell of gases that surround Earth. Air is the common name for the gases that make up the atmosphere. Composition of the Atmosphere Nearly 99% of the atmosphere is made of nitrogen and oxygen. There are other trace gases found in air. We will consider several of them in addition to nitrogen and oxygen. 1.
2.
3.
4.
5.
6.
Nitrogen. The majority of the atmosphere is made of nitrogen. Nitrogen is important to the atmosphere because it helps create air pressure. Too much or too little nitrogen in the atmosphere changes air pressure. Oxygen. The second most abundant gas in the atmosphere is oxygen. Oxygen is vital to living things. Without oxygen, animals and other organisms would die. However, too much oxygen is toxic to some living things. Argon. Argon is the third most common gas in the atmosphere - although its abundance is extremely small. Its importance to the atmosphere is unknown. For this reason, we often forget about this gas in the atmosphere. Carbon Dioxide. Carbon dioxide is a trace gas found in the atmosphere. It is important to plants and photosynthesis. CO2 is a greenhouse gas. A greenhouse gas is a gas that helps keep Earth warm. Too little carbon dioxide is harmful to plants and could cause temperature on Earth to decrease. Too much CO2 could cause Earth to become too warm. Water Vapor. Water vapor is a trace gas found in the atmosphere, although its percent abundance varies greatly. It is important to the water cycle. It is also the most important greenhouse gas that keeps Earth warm. Like other greenhouse gases, it “blankets” Earth, trapping heat. Too little water vapor could cause Earth to become cold. Too much could cause Earth to become too warm. Ozone. Ozone is a trace gas. It most important to the formation of the ozone layer in the stratosphere. This gas forms a layer (the ozone layer) which blocks UV light. Too little ozone creates holes in the ozone layer, allowing more UV light to reach Earth’s surface. Too much is toxic to living thing.
Considerations: - There are other trace gases found in the atmosphere. These gases include neon, helium and methane. Methane is a greenhouse gas like CO2 and water vapor. - The composition of air in each atmospheric layer varies. For example, water vapor is only found in the troposphere. The majority of ozone (97%) is found in the stratosphere.
Chapter 10: Atmospheric Gases INB Activity Directions: Cut out the table. First, create a circle graph to show the composition of gases in the atmosphere. Correctly label each sector on the graph. Then describe the importance of different gases in the atmosphere. Describe what would happen if there was more or less gas in the atmosphere. Atmospheric Gases Gases found in Earth’s Atmosphere Gas
