Layers of the Atmosphere Lab

Layers of the Atmosphere Lab

Name ______

Question:How are the layers of Earth’s atmosphere distinguished from one another?

Introduction:

The atmosphere can be divided into four layers based on temperature variations. The layer closest to the Earth is the troposphere. Above this layer is the stratosphere, followed by the mesosphere, and then the thermosphere. The upper boundaries between these layers are known as the tropopause, the stratopause, and the mesopause respectively.

Temperature variations in the four layers are due to the way solar energy is absorbed as it moves downward through the atmosphere. The Earth’s surface is the primary absorber of solar energy. Some of this energy is reradiated (bounces off) by the earth as heat, which warms the troposphere above. The global average temperature in the troposphere rapidly decreases with altitude until the tropopause, the boundary between the troposphere and the stratosphere.

The temperature begins to increase with altitude in the stratosphere. This warming is caused by a form of oxygen called ozone (O3 ) absorbing ultraviolet radiation from the sun. Ozone protects us from most of the sun’s ultraviolet radiation, which can cause cancer, genetic mutations, and sunburn. Scientists are concerned with the level of ozone in the stratosphere. Certain chemicals such as nitric oxide and chlorofluorocarbons deplete the stratospheric zone. The use of these chemicals have been banned in a worldwide treaty called the Montreal Protocol (1989). Since the passage of this, ozone levels have recovered somewhat, and are predicted to be completely recovered by the year 2050.

At the stratopause, the temperature stops increasing with altitude. The mesosphere above this does not absorb solar radiation, so the temperature decreases with altitude. At the mesopause, the temperature begins to increase with altitude, and this trend continues into the thermosphere. Because the atmosphere is so thin, a thermometer cannot measure the temperature accurately, and special instruments are needed.

Procedure:

Table 1 contains temperature readings at various altitudes in the Earth’s atmosphere.

1. Plot this data on the graph on the worksheet provided.
2. Connect the points with a solid line. (This profile provides a general picture of the conditions in the atmosphere at any given time and place, however actual temperature values may deviate, particularly in the lower atmosphere)
3. Label the different layers of the atmosphere and the separating boundaries between each layer.
4. Mark the general location of the ozone (information is in the reading)

Table 1 Average Temperature Readings at various altitudes

Discussions Questions:

1. From the graph…at what elevation is the highest temperature? ______

1. From the graph…. What is the highest elevation? ______

1. What is the observation that scientists use to divide the atmosphere into four layers? (Infer from the reading)

1. Does the temperature INCREASE or DECREASE as you increase altitude in each of the following spheres?

1. Troposphere ______
2. Stratosphere ______
3. Mesosphere ______
4. Thermosphere ______

1. What is the altitude (km) and the temperature (° C) of each of the atmospheric boundaries?

1. Tropopause ______(km) / ______(° C)
2. Stratopause ______(km) / ______(° C)
3. Mesopause ______(km) / ______(° C)

1. What causes the increase in temperature in the stratosphere? (From the reading)

1. In conclusion: Write a paragraph discussing the Scientific Question (from the lab) and what you learned from this activity.