Each statement represents a primary learning objective for parts of this unit. After you complete the unit, you should be able to:

• List and describe the sciences that collectively make up Earth science.

• Discuss the scales of space and time in Earth science.

• Discuss the nature of scientific inquiry, including the construction of hypotheses and the development of theories.

• Outline the stages in the formation of our solar system.

• List and describe Earth’s four major spheres.

• Define system.

• Explain why Earth is considered to be a system.

• List and describe the major features of the ocean basins and continents.

The spectacular eruption of a volcano, the magnificent scenery of a rocky coast, and the destruction created by a hurricane are all subjects of interest for an Earth scientist. The study of Earth science deals with many fascinating and practical questions about our environment. What forces produce mountains? Why is our daily weather variable? Why is Earth’s climate changing? How old is Earth, and how is it related to other planets in the solar system? What causes ocean tides? What were the Ice Ages like, and will there be another? Where should we search for water?

The subject of this text is Earth science. To understand Earth is not an easy task because our planet is not a static and unchanging mass. Rather, it is a dynamic body with many interacting parts and a long and complex history.