Barb Lavelle

Science

Grade 3

 

Lesson: Soil Layering

 

Objectives:

  1. Students will estimate how much of the earth’s surface is soil.
  2. Students will combine different soil samples brought in from home.
  3. Students will predict the outcome of mixing their soil samples with water and shaking them.
  4. Students will observe and describe the soil layers by recording drawings in their soil booklets.

 

Procedures:

 

  1. Using the projector, access the site below showing the apple representation of planet Earth. As you progress through the site, demonstrate with a real apple exactly what is being done online at:

    http://soil.gsfc.nasa.gov/app_soil/hmsoil.htm
  2. Allow students to make predictions of how much of the apple’s skin will represent the amount of Earth’s soil.
  3. Empty soil samples collected from students and combine in larger container.
  4. Pair off students with each pair getting a soil tube and cup for water. (You can even have a tube mixed with class soil samples of clay, pebbles, organic matter, sand and silt. That way you can be assured of several layers for them to see.)
  5. While one student comes up to the table to get soil, their partner fills the cup with water. Both students return to their seats and draw in their soil booklets what they think the tube will look like hours from now.
  6. Students then fill the rest of the tube (about an inch from the top) with water. Students shake vigorously (being careful the lid stays on tight).
  7. Allow tubes to stand overnight. The next day, allow students to get their tubes and observe what happened. Were their predictions accurate?
  8. Ask students to draw the new results in their booklet and answer the questions:
    1. How many layers do you see?
    2. How big are the pieces on the bottom?
    3. How big are the pieces on the top?
    4. Is there anything floating on top?
  9. Allow students time to compare their tubes of soil. Discuss differences and similarities.
  10. Use layered soil tubes to identify humus, sand, silt, clay, and rocks.

 

Assessment: Observe student drawings from day #1 to day #2. Day 2 should show the layering that occurred overnight.