Questions

Review Questions

Question 5.1

How does water falling as snow atop a mountain eventually become a cloud?

Question 5.2

What is unique about the behavior of water compared to other common substances?

Question 5.3

How does the greenhouse effect influence the temperature of the atmosphere? Which properties of greenhouse gases in the atmosphere cause this effect?

Question 5.4

How do we know that Earth was once entirely molten?

Question 5.5

What are the different types of seismic waves? Why are seismic waves useful for probing Earth’s interior structure?

Question 5.6

Describe the interior structure of Earth.

Question 5.7

The deepest wells and mines go down only a few kilometers. What, then, is the evidence that iron is abundant in Earth’s core? That Earth’s outer core is molten but the inner core is solid?

Question 5.8

Describe the process of plate tectonics. Give specific examples of geographic features created by plate tectonics.

Question 5.9

Explain how convection in Earth’s interior drives the process of plate tectonics.

Question 5.10

Describe the various ways in which Earth’s surface is reshaped over time.

Question 5.11

Describe Earth’s magnetosphere. If Earth did not have a magnetic field, do you think aurorae would be more common or less common than they are today?

Question 5.12

Ozone and carbon dioxide each make up only a fraction of a percent of our atmosphere. Why, then, should we be concerned about small increases or decreases in the atmospheric abundance of these gases?

Question 5.13

What is the difference between ozone depletion and global warming?

Web Chat Questions

Question 5.1

The human population on Earth is currently doubling about every 30 years. Describe the various pressures placed on Earth by uncontrolled human population growth. Can such growth continue indefinitely? If not, what natural and human controls might arise to curb this growth? It has been suggested that overpopulation problems could be solved by colonizing the Moon or Mars. Do you think this is a reasonable solution? Explain your answer.

Question 5.2

In order to alleviate global warming, it will be necessary to dramatically reduce the amount of carbon dioxide that we release into the atmosphere by burning petroleum. What changes in technology and society do you think will be needed to bring this about?

Collaborative Exercises

Question 5.1

Using a ruler and self-stick or tape-on labels, create a scale model of Earth on the shortest member of your group. Use the group member’s height in inches divided by Earth’s diameter (12,800 km) as the scale factor. For example, if the selected group member is 65 in. tall then the 50-km maximum depth of Earth’s crust is (65 in. ÷ 12,800 km) × (50-km) = 0.25 in. from the top of the head and 0.25 in. from the bottom of the feet.

Observing Questions

Question 5.1

Use Starry Night™ to view Earth from space. Open the view named Favourites > Explorations > Earth’s Surface. The view shows the rotating Earth from a point in space about 12,000 km above the surface. The clouds and atmosphere have been removed from the image, and the side of Earth facing away from the Sun is artificially brightened so that you may use the location scroller and Zoom controls to inspect the entire surface of our home planet. (a) Can you see any evidence of plate tectonics on Earth? (b) Can you see any evidence of life or of man-made structures or objects?

Question 5.2

Use Starry Night™ to view Earth from space. Select Favourites > Explorations > Earth from the menu to place yourself about 12,238 km above Earth’s surface. Use the location scroller to rotate Earth beneath you, allowing you to view different parts of its surface. Is there any evidence for the presence of an atmosphere on Earth? Explain.

Question 5.3

Use Starry Night™ to view Earth from space. Click the Home button in the toolbar to move your viewing location to your hometown or city. Click the Increase current elevation button beneath the Viewing Location panel in the toolbar to raise your position to about 11,000 km above your home location. Use the hand tool to move Earth into the center of the view. Locate the position of your home and zoom in on it, using the Zoom tool on the right of the toolbar to set the field of view to about 16° × 11°. Use the location scroller to move over various regions of Earth’s surface. (a) Can you see any evidence of the presence of life or of man-made objects? (b) Right-click on Earth (Ctrl-click on a Mac) and select Google Map from the contextual menu to examine regions of Earth in great detail on these images from an orbiting satellite. (You will need to have access to the Internet in order to use Google Map.) You can attempt to locate your own home on these maps. As an exercise, find the country of Panama. Zoom in progressively upon the Panama Canal and search for the ships traversing this incredible waterway and the massive locks that lift these ships into the upper waterways. What does this suggest about the importance of sending spacecraft to planets to explore their surfaces at close range?

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