LabLearner—The Science of Learning
LabLearner—The Science of Learning

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Atmosphere

Investigation 1 – PreLab

 

 

 

 

 

 

 

Back to Investigation 1

ZERO-IN

Italicized font represents information to be shared orally or physically completed with the students at this time.

The non-italicized font represents additional information included to support the teacher’s understanding of the content being introduced within the CELL.

ASK WHY

Remind students that Earth’s atmosphere is critical for life on our planet. It protects us from dangerous radiation from the sun and other objects coming at us from outer space, holds in surface heat and prevents it from radiating out into space, provides weather, makes flight possible, and, ultimately, allows us to talk with each other. 

BRANCH OUT

Remind students that meteorologists track hurricanes to alert people about its path, which could save thousands of lives.

GET FOCUSED

Inform students that the Investigation is designed to help them to answer the following Focus Questions:

  • What happens to air as it is heated and cooled? The volume and density of air change with changes in temperature. As the temperature of air increases, its volume increases, and its density decreases. As the temperature of air decreases, its volume decreases, and its density increases.
  • How do changes in the temperature of air affect its density? As air is heated its density decreases because its mass remains constant but its volume increases. As air is cooled, its density increases because its mass remains constant but its volume decreases.
  • Why do changes in density cause air movement? Air is a fluid. Fluids that are more dense sink below those that are less dense. The decrease in density as air is heated causes it to rise above cooler, more dense air. The increase in density as air is cooled causes it to sink below warmer, less dense air.
  • How do differences in the temperature of the Earth’s atmosphere affect the movement of air? The warmer air in the atmosphere rises and cooler air in the atmosphere sinks. This causes convection currents in the atmosphere.

Note: These questions are located in students’ SDRs at the beginning and end of the Investigation.

Note: These are succinct responses to the Focus Questions and are placed here for your reference at this time. Fully developed responses to the Focus Questions can be found on the PostLab page.

GO DEEPER

As a class, read the Background(s) in the Investigation. Have students read the information aloud or silently to themselves. When students have finished, discuss the following concepts as a class:

  • The atmosphere is a thin layer of gases that surrounds the Earth.
  • The atmosphere consists mainly of the gases nitrogen, oxygen, and argon. Nitrogen makes up 78% of the atmosphere. Oxygen makes up 21% and argon makes up approximately 0.9% of the atmosphere.
  • The atmosphere is held in place around the Earth by Earth’s gravity.
  • The atmosphere has several layers.
  • Most of the Earth’s weather occurs in the bottom layer of the atmosphere called the troposphere.
  • The troposphere is heated by UV light and other forms of energy from the Sun which are absorbed or reflected by water and land.
  • The heat absorbed by the land or water is transferred to the air directly above the land or water by conduction and radiation. 
  • All areas of the Earth do not receive the same amount of light and other electromagnetic radiation.
  • Because the Earth is tilted 23.5º on its axis, the angle at which light hits the equator is more direct than the areas away from the equator.
  • The north and south poles receive the least amount of direct light.
  • Differences in the amount of direct light cause differences in the amount of heat. More direct light results in more heat that is received. Less direct light results in less heat that is received. 
  • Gases behave in certain, predictable ways. One of the ways in which gases behave is described by the scientific principle known as Charles’ Law.
  • Charles’ Law describes how the volume changes with changes in temperature when the pressure of a gas is constant; as the temperature of a gas increases, the volume of the gas increases.

Note: These concepts are integrated into the Background(s) and are used to deepen students’ comprehension of the big ideas.

 

LEARN THE LabLearner LINGO

The following list includes Key Terms that are introduced in the Investigation Background(s). They should be used, as appropriate, by teachers and students during everyday classroom discourse.

  • density
  • atmosphere
  • Charles’ Law
  • troposphere

Note: Definitions of these terms can be found on the Introduction page to the CELL.

Note: Additional words may be bolded within the Background(s). These words are not Key Terms and are strictly emphasized for exposure at this time.

 

SET FOR SUCCESS

  • Explain to students that the focus of this Investigation is to better understand the changes that can occur to the atmosphere and how these changes result in changes in the weather.
  • Inform students that the changes in weather that will be examined are the temperature, pressure, and precipitation received by different areas on Earth.
  • Assess students’ prior knowledge and their understanding of the atmosphere and weather by asking the following questions. Student answers will vary.
    • What does someone mean when they talk about “the weather?”
    • What causes weather?
    • Where is the atmosphere and what is its composition?
    • Are all areas of the atmosphere the same?
  • Review what students know about temperature and precipitation.
  • Ask for several student volunteers to describe the relationship between temperature and kinetic energy.

Note: Students should be able to describe temperature as a measure of the kinetic energy of the molecules of a solid, liquid, or gas. In addition, students should generate ideas about precipitation that include: Precipitation as part of the water cycle, and precipitation occurs in solid and liquid forms such as rain, snow, hail, freezing rain, and sleet.

  • Encourage students to share their ideas about pressure. If necessary, briefly describe pressure as the force exerted per area of an object or substance.
  • Tell students that one type of pressure, atmospheric pressure, and its relationship to weather changes, will be discussed further during Investigation Two.
  • Emphasize that students will begin their exploration of the atmosphere and weather by focusing on the changes that occur to air as it is heated and cooled.
  • Instruct students to look at the Focus Questions again. Encourage them to make suggestions as to which physical characteristics of air they should focus on as they conduct their experiment. Help students understand that the Focus Questions make reference to temperature and density, therefore students should think about the changes in temperature and density that may occur to air.
  • Assess students’ prior knowledge and their understanding of the temperature, density, and weather phenomena by asking them to discuss the answers to the following questions. Students will formulate answers to these questions after they have completed the Investigation.
    • Where does weather occur? •
    • What is density? How is it calculated?
    • How do fluids of different densities behave when mixed together? 
    • How do changes in the atmosphere cause changes in the weather?
  • If necessary briefly review the concept of density.
    • The density of a substance is a measure of the amount of matter contained within a certain volume of a substance.
    • Re-acquaint students with the formula for calculating density: Density= mass/volume
    • Discuss the concept of density within liquids. Remind students that if immiscible liquids of two different densities are combined, the more dense liquid will sink below the less dense liquid.
  • Explain to students that liquids have certain ways in which they respond to changes in some of their physical characteristics such as density and response to a force. Because of these ways, scientists refer to liquids as fluids. Inform students that scientists also consider gases such as “air” fluids.
  • Play the video below. Stop to ask students questions or answer students’ questions when necessary. Remind students to follow along with their SDRs and make any notes that they think might be helpful.
  • After the video, direct students to divide into their lab groups to discuss their strategy for the lab. For example, they may assign certain group members to perform specific functions during the lab.

Note: The purpose of the video is to allow students to anticipate the laboratory experience they will soon encounter. Students should leave this PreLab session with a firm idea of what to expect and how to perform in the lab.

Note: Homework is posted below the video.

 

HOMEWORK

Tell students that they should review the Investigation in preparation for the Lab.