I.A.2 Part Two—Pits in the Sand
This activity is designed to show that the circumference of a pit that can be dug depends on the depth of dry sand available. It will also show the effectiveness of various kinds of digging tools and introduces a tricky, but very important concept: sometimes we can get useful answers even when we ask misdirected questions.

Materials:
Each team of four students needs:
  • Shoe box
  • Dry sand (enough to make 11/2 inches in the box)
  • Plastic spoon
  • Plastic fork
  • Pencil (for digging)
  • Popsicle stick
  • Ruler
  • Small piece of paper
  • Pencil
Instructions for the teacher:
  1. Divide students into teams of four. Each member of the team should have a different digging tool.

  2. Write the following question on the board or overhead projector: Which digging tool can make the largest pit? Have teams decide amongst themselves and write their answer down on a piece of paper.

  3. Tell students that, one at a time, they will each dig a pit in the sand with their digging tool. Once they reach the bottom of the box, they will stop and measure the diameter of the pit. Show students how to measure the diameter of a pit. Once the pit is measured and the diameter is recorded, students will level the sand in the box.

  4. Have students begin digging with their tools, one at a time. Remind them to measure the pit once they reach the bottom, and write the answer on a piece of paper. Continue until all team members have had the opportunity to dig and measure their pits.

  5. Copy the table below on the chalkboard or overhead projector. Collect data from all the teams and put the results on the table.



    6. Pit Diameters:

    Team Spoons Forks Pencils Popsicle sticks
             
             
             
             
             
             
             
             



  6. Find the average diameter for each column. The average diameter for all columns should be similar—which, most likely, is not what most students expected.

  7. Ask your students: If the type of digging tool is not important, then what is? (The time it takes to dig the burrow and how deep the burrow needs to be.)

Notes

The additional activity below is intended to get students to use what they now know about sand and think about animal adaptations:

Ask your class the following question: Ant lions make pits in sand that other insects fall into. Why don’t any big animals make pits in sand?

Assign each team of four students an animal that must catch its prey in a sand trap: a pit-fox, a pit-turtle, a pit-snake, a pit-bobcat, etc.

  • What special problems might a large animal have as a pit-maker?
  • What special features would they give their animal to make it easier to live and dig in the sand?
  • Draw the animal.

Results
After completing this activity, students should:

  • Understand that sand is easy to dig in.
  • Understand that sand is an unusual but predictable material.
  • Understand that the circumference of a pit enlarges as the depth of the pit increases.
  • Understand that the adaptations scrub animals have for digging can assume a variety of shapes and sizes.
I.A.2-Part 1    Part 2
A. Physical Properties of Sand     I.A.1     I.A.3
B. Animal Tracks in the Sand     I.B.1
C. Glossary     D. Questions for Student Evaluation