Chapter 9 Lesson 2 "Layers of the Atmosphere"

Materials:

• Worksheet, "Layers of the Atmosphere"
• (Lead teacher will need a jar of cooking oil and a small diameter tube)

Objective:

• Students will identify the four layers of the atmosphere.
• Students will name one characteristic of each layer.

Anticipatory Set:* Show the students a jar of cooking oil. with a small diameter straw or tube blow a small bubble into the bottom of the jar and watch it rise. Ask the students if they notice a change in the bubble as it rises from the bottom to the top. As it rises the bubble rises it should enlarge. Ask the students why this happens. Draw a column and show the concentration of oil, water, or air molecules in the column. Start by putting the molecules equal spaced apart from top to bottom and ask what gravity does to the molecules. Increase the density of the molecules on the bottom. Show how the molecules making up the bubble would be able to expand as they rise. This phenomenon makes the atmosphere very complex. It changes the temperature, pressure, and chemical composition as you move up in the atmosphere.

Explain the theory again using a man who is climbing a tall mountain. Or why a runner from Ethiopia has a training advantage over someone from sea level.

Teacher Input:* Since the characteristics of air change as you go up in elevation scientists have divided the atmosphere into different layers based on how high in the air you are. Atmosphere Layers. (Identify the Thermosphere, Mesosphere, Stratosphere, and Troposphere)Each of the layers then have different characteristics. Now lets look at the characteristics of each.

Troposphere: Bottom layer of the atmosphere, extending from the ground level up to about 16 Kilometers, Most weather occurs in this level. Most thunderhead clouds end at the stratosphere.

The Stratosphere contains the ozone layer and an increase in temperature. Air temperature increases with height.

The Mesosphere is the coldest layer of the atmosphere as temperature decreases with heightagain. Most meteorites burn up in this layer.

The thermosphere is the outermost layer. Temperatures are much higher up to 2000 degrees Celcius.The upper thermosphere is called the ionosphere because the high energy from the sun at this level can strip electrons from the Nitrogen and Oxygen particles at this level. AM and short wave radio waves bounce off these ions and are sent back to the earth. This can enable you to hear radio stations from hundreds of miles away.

Guided Practice:* Students will complete the Questions on Page 210 together in class.

Independent Practice:* Students will complete the worksheet, "Layers of the Atmosphere"

Check for Understanding:* Students will take the quiz over Lesson 2, "Layers of the Atmosphere"

Duration:

30 minutes + 10-15 for Independent Practice (Could be longer if taken for homework).

Alaska Content Standards Addressed in this lesson:

• SCI A-1 Students will understand models describing the nature of molecules, atoms, and sub-atomic particles and the relation of the models to the structure and behavior of matter (Structure of Matter);
• SCI A-4 Students will understand observable natural events such as tides, weather, seasons, and moon phases in terms of the structure and motion of the earth (Earth);
• SCI A-5 Students will understand the strength and effects of forces of nature, including gravity and electromagnetic radiation (Forces of Nature);

• SCI A-15 Students will use science to understand and describe the local environment (Local Knowledge); and: