4.1 A Planetary Overview

It’s easy to take the beauty of our planet for granted, which is part of why it is so important to understand what Earth is like on a planetary scale. This particular photograph was taken on the island of Nuku Hiva in French Polynesia. Do you have a favorite landscape photograph of your own?

If you go for a daytime walk in nature or in a park, the world may not look much different today than it did to our ancestors long ago. Just as they saw, you’ll see rocks of different types, plants and animals, water, and when the sky is clear, a seemingly endless blue sky. The big difference between our modern view and the view of our ancestors is not in the things we see, but rather in the context through which we understand them.

In this first section, we’ll explore the modern context through which we understand our planet. In essence, we’ll develop a “big picture” view of the Earth: what it looks like, how it changes, and how we study it.

Section Learning Goals

By the end of this section, you should be able to give general answers to the following questions:

What does Earth look like on the outside?
What does Earth look like on the inside?
How has Earth changed through time?
How do we study the Earth?

Before you continue, take a few minutes to discuss the above Learning Goal questions in small groups or as a class. For example, you might discuss what (if anything) you already know about the answers to these questions; what you think you’ll need to learn in order to be able to answer the questions; and whether there are any aspects of the questions, or other related questions, that you are particularly interested in.

Journal Entry

Local Photo Journal

Look through your personal photo collection, or take new photos if needed, to make a journal entry in which you paste 3 to 5 of your favorite photos of your local landscape. Try to choose photos for which you can draw a connection between what is visible in the photo and the larger context of our planet Earth. For each photo, write a paragraph or two about what natural phenomena are visible in the photo, about how these phenomena connect to the larger context of planet Earth, and about why you chose each particular photo. Hint: A few examples might include: connecting what you see in the sky to the atmosphere or weather; connecting landscape features to natural resources or Earth’s geological history; connecting water features to the oceans or water cycle.

Show Teachers Notes

The goal here is simply to get students thinking about how local phenomena are globally connected. The journal entries might be quite wide-ranging, so for grading, look for thoughtfulness. Some examples of the types of connections students might draw:

Connecting the sky visible in a local photo to the larger context of Earth’s atmosphere.
Connecting a weather phenomenon (e.g., cloud, rain) to global weather patterns and circulation.
Connecting a lake or stream to the water cycle, or a beach to the global ocean system.
Connecting a hill or mountain or rock formation to global geology.
Connecting trees to the cycling of carbon dioxide or even to global warming.
Connecting birds with their migration patterns and reasons for their migrations.
etc.

Connections—Etymology

geo

Throughout this and the remaining chapters we will use numerous words that start with the Greek root geo, which means “Earth.” For example:

The Greek root logy means “the study of,” so, geology is literally “the study of the Earth” and a geologist is a scientist who engages in this study.
The suffix graphy comes from a Greek root meaning “to write about,” so geography is writing about the Earth, which we generally take to mean describing or mapping the Earth.

Note that while geo could in principle apply to any aspect of Earth, we generally think of it as applying to Earth’s surface and interior, but not to the oceans or atmosphere. For example, we count mountains and caves as geological features, but not winds or ocean currents. More specifically, today we think of geology as the study of any aspect of Earth’s structure, history, or processes. For example, if you say “I am studying the geology of the Rocky Mountains,” it could mean you are studying the types of rocks found there, the overall structure of the mountains, the history of the mountains, or the processes that made them.

Note also that it is now common to apply the root geo not only to the study of Earth, but also to the study of any other world with a solid surface. For example, when we talk about the geology of the Moon or Mars, we are talking about the study of features found on these worlds.

Activity/Journal Entry

Google Earth

Google Earth opens only in the Chrome browser. Open that browser, and go to https://www.google.com/earth/, then do the following:

Read through the home page to get a sense of the types of things you can do with Google Earth. Then click the “Launch Earth” button to get started with the app. You will see that the app opens with a full globe view of Earth.
Explore how you can rotate the globe, or zoom in or out, to see particular features. Notice how the globe represents depths in the ocean.
Rotate the globe so that your location is in view. Then choose the icon that “flies in” to a close-up view of your location.
Gradually zoom out from your location to explore the region around you. Where are the nearest lakes or streams? Where are the nearest hills or mountains? What other features make your location geographically interesting?
In your journal, write a paragraph or two describing your local region based on what you see in Google Earth.
Click the icon for the “Voyager” feature, then explore one Voyager project of your choice.
In your journal, write down the name of the Voyage project your explored, and write one paragraph describing what the project showed, and then add a brief list of at least 5 things you learned from the project.