Soil is the name given to the material found above the solid rock of the earth. It consists of particles worn from rock mixed with decaying animal and vegetable matter. There are some easily recognizable common types of soil-clay, gravel, sand-which differ in texture. Some are made up of finer particles than others and in some the particles are more closely packed than in others. For these reasons, different types of soil (aquifers) differ in the degree to which they hold water.
What you need:
What you do:
1. Use the scissors to carefully cut the bottoms off of the bottles.
2. Have an adult help you build a small plywood stand to hold the bottles upside down.
3. Tape a piece of gauze over the mouth of each bottle. Fill one with gravel and sand, a second with sand and topsoil, the third with topsoil and clay, and the fourth with clay. Place bowls under each mini-aquifer to catch the drippings.
4. With a partner, pour one cup of water into the top of each bottle at exactly the same time. Observe the length of time it takes water to pass through each type of soil mixture. Do you think farmers needs to know which type of aquifer holds water best and which loses it fastest?
Used with permission from
Science Activities from A to Z
by Dr. Helen Challand and Elizabeth Brandt with illustrations by Herb Rudd.
Courtesy Digital Atlas of Idaho 2000.