This lesson introduces students to canyons and has them compare canyons to mountains and plains. They will look at photographs of three canyons and then focus on the Grand Canyon, discussing how the Colorado River carved it into its present form. They will conclude by drawing pictures of the Grand Canyon and writing captions or drawing additional pictures to describe how the canyon was formed.

Geography, earth sciences

Standard 7: "The physical processes that shape the patterns of Earth's surface"

One to two hours

• Computer with Internet access
• Map of the United States, showing the location of the Grand Canyon

Students will

• compare photographs of three canyons;
• compare canyons to mountains and plains;
• brainstorm how the Grand Canyon might have been created;
• discuss how the Colorado River carved the Grand Canyon; and
• draw pictures of the Grand Canyon with captions explaining how it was formed.

Write the word "canyon" on the board. Ask students if they know what a canyon is, and discuss their ideas.

Explain that a canyon is a deep valley with very steep sides, usually carved by a river.

Have students look at these pictures of canyons, and discuss what they all have in common:

• Grand Canyon (Arizona)
• Hells Canyon (Oregon/Idaho)
• Kings Canyon (California)

Explain that canyons are very different from other physical features students may be familiar with. To illustrate this point, have students look at the following photographs:

National Geographic: Grand Canyon Photographs
National Geographic Magazine: Mountains—Sherpas
National Geographic Magazine: Great Plains—Change of Heartland (look at the landscape where the farmers are standing)

Discuss the differences between canyons, mountains, and plains, using examples from the photographs students have seen.

Point out the location of the Grand Canyon on a United States map, and explain that this is probably the best known canyon in the world. Millions of people visit the Grand Canyon each year to enjoy its beauty.

Have students return to the photograph of the Grand Canyon. Ask them how they think the Grand Canyon might have been formed. List their ideas on the board or discuss them as a class.

Ask students to look carefully at the above photograph to find the Colorado River at the bottom of the canyon.

Explain that over millions of years, the Colorado River carved the Grand Canyon out of the rock. Provide these analogies to help students understand this concept:

• After it rains hard, you can sometimes see tiny "rivers" carving into the dirt. The faster the water moves, the deeper it can carve these little "rivers."
• If you've ever built a sandcastle at the beach, the water eventually comes up and washes the sandcastle away.
• If there's a river in your town, you can go there and look at the riverbanks. These banks have been carved out by the river over time, much as the Colorado River has carved the Grand Canyon.

Students should have noticed that each of these examples shows how water can carve features out of the land, whether in a small area, such as a sandcastle, or in a huge area, such as the Grand Canyon.

Have students look at additional Grand Canyon photographs. Discuss what the landscape looks like and what it might be like to take a hike around or in the canyon. Inform students that in some places, the canyon is a mile deep; compare this distance to a mile's walk in their town.

Also tell them that the canyon is over 200 miles (320 kilometers) long and 18 miles (29 kilometers) wide at its widest point. Compare these distances to distances in your region (e.g., New York City to Washington, D.C. is approximately 230 miles; your town to another town might be around 18 miles).

Have students draw pictures of the Grand Canyon and write captions below the pictures that explain how the canyon was formed. If your students are not yet writing, have them draw pictures showing the river in the process of carving the canyon.

Have students draw a mural of the Grand Canyon on poster paper. The mural should show as many of the canyon's layers as possible and the Colorado River at the bottom of the canyon. After they have drawn the canyon and river, have them research the plants and animals that live in the Grand Canyon, and ask them to add some of these to the mural. They can find information about plants and animals at these Web sites:

National Geographic: Grand Canyon—Interactive Map of the South Rim (click on the icons for "Plant Life" and "Canyon Creatures")
Outdoors Unlimited River Trips: Plant and Animal Photos
PBS: Meeting the Natives
Wildlife and Plant Life of the Grand Canyon

National Geographic: Grand Canyon—The Hidden Secrets
The American Southwest: Grand Canyon National Park