Teacher Site Map 4thGrade Core USOE Science Home Page USOE

# Keeping Soil In Its Place.

We need plants to eat. Plants need soil to grow. So in a weird way, we need soil to eat! Soil is a very valuable resource, and there isn’t much of it.

DO IT!
You know how important water is to life on our planet. Almost all living things depend on it to survive and thrive. Just like water, soil is a major natural resource. Soil is like the skin of the Earth. There is a lot of action, reaction, and interaction going on to make soil. The amount of topsoil that is usable for crop production is only a very small percentage. Who should care? EVERYONE! The following activity demonstrates the value of Earth's soil.

Try It!

Make sure you get permission from an adult.

Materials:

• One apple
• Knife to cut the apple (Be sure to get an adult to help you do this.)
• Paper towels for clean up

Procedure:

1. Imagine Earth as an apple.
2. Cut the apple into four equal parts. Only one of these sections represents land. Explain why. Set the other three pieces aside.
3. Cut the land piece in half. One of these sections represents the land area that is covered with mountains, deserts, or ice. Set it aside. The other piece represents livable land.
4. Cut the “livable” area into fourths. Three of these sections are rocky, wet, hot, infertile or covered with roads and cities. Set them aside.
5. How much of the apple is now remaining? If you have done your math correctly, you now only have 1/32 of the original apple. This is the part of Earth that can be used for farming.
6. Peel the skin from the farming section of the apple. This represents the topsoil on which the food is grown. This small amount of “soil” must “feed” all of the people on this planet.
7. Go ahead, eat your apple and don't forget to clean up your mess!

Analysis:
Write a short summary of this activity. Include a paragraph on the importance of soil to life on Earth.

Plant It!
Topsoil is valuable. We must find ways to conserve it and keep it from eroding away. One of the best ways to conserve soil is to plant... plants! The roots of plants help to anchor the soil to the ground preventing the wind and/or water from removing it.

You easily can see how plants hold soil. Find a grassy spot on a little hill. Turn the hose on the grass. Observe. Find a section of open dirt on a similar hill. Run the hose. Observe. You should notice soil moving from the plain dirt location, and see little or no dirt running from the grassy slope. The grass is holding onto the soil!

Download the plug-ins: , and . (The QuickTime plug-in is needed to play sounds and movies correctly.)

Want to share photos of you or your friends doing this activity? Send it in an e-mail with the following information:

1. The title of the activity
2. The URL (Internet address)
3. Your name.

Remember that no pictures can be used that show student faces or student names on it.

Teachers should view the Teacher Site Map to relate Sci-ber text and the USOE 4th grade science core.

Updated October 24, 2008 by: Glen Westbroek

Science Home Page | Curriculum Home Page | 4th Grade Science Core Home Page | USOE Home Page

Copyright © Utah State Office of Education.