Category: 8. Earth as a Planet

Collaborative Group Activities

For Further Exploration Articles Earth Collins, W., et al. “The Physical Science behind Climate Change.” Scientific American (August 2007): 64. Why scientists are now confident that human activities are changing our planet’s climate. Glatzmaier, G., & Olson, P. “Probing the Geodynamo.” Scientific American (April 2005): 50. Experiments and modeling that tell us about the source and reversals of Earth’s…

Learning Objectives By the end of this section, you will be able to: In discussing Earth’s geology earlier in this chapter, we dealt only with the effects of internal forces, expressed through the processes of plate tectonics and volcanism. On the Moon, in contrast, we see primarily craters, produced by the impacts of interplanetary debris such…

Learning Objectives By the end of this section, you will be able to: As far as we know, Earth seems to be the only planet in the solar system with life. The origin and development of life are an important part of our planet’s story. Life arose early in Earth’s history, and living organisms have been interacting…

Learning Objectives By the end of this section, you will be able to: We live at the bottom of the ocean of air that envelops our planet. The atmosphere, weighing down upon Earth’s surface under the force of gravity, exerts a pressure at sea level that scientists define as 1 bar (a term that comes from…

Learning Objectives By the end of this section, you will be able to: Let us now examine our planet’s outer layers in more detail. Earth’s crust is a dynamic place. Volcanic eruptions, erosion, and large-scale movements of the continents rework the surface of our planet constantly. Geologically, ours is the most active planet. Many of the…

Learning Objectives By the end of this section, you will be able to: Earth is a medium-size planet with a diameter of approximately 12,760 kilometers (Figure 8.2). As one of the inner or terrestrial planets, it is composed primarily of heavy elements such as iron, silicon, and oxygen—very different from the composition of the Sun and…

Airless worlds in our solar system seem peppered with craters large and small. Earth, on the other hand, has few craters, but a thick atmosphere and much surface activity. Although impacts occurred on Earth at the same rate, craters have since been erased by forces in the planet’s crust and atmosphere. What can the comparison…