Night Creatures of the Kalahari

Teacher Instructions

Food Chain Chambers

Materials for four chambers

  • 8 two-liter soda bottles
  • 4 soda bottle caps
  • utility knife
  • hammer
  • nail
  • permanent marker
  • 3 spiders
  • 4 twigs
  • banana slices

Directions for One Chamber

  1. Remove the labels from the bottles.

  2. Cut bottle #1 between the shoulder and the neck—about 2.5 cm (1 in.) above the shoulder. Remove the top part.

    Bottle diagram 1 - 2 liter bottle cut at shoulder
  3. Unscrew the cap from the top of bottle that you just cut. Punch a hole in the cap using a hammer and nail. The hole should be about 2 mm (.08 in.) in diameter. Screw the cap back on.

  4. Cut the second bottle 2.5 cm (1 in.) above the hip.

    Diagram: cut the second bottle above the hip
  5. Fit the top of bottle #1—cap pointing up—into the bottom of bottle #2. This will be the fruit fly chamber.

    Diagram: top of bottle 1 fit into bottom of bottle 2
  6. Invert the remainder of bottle #1 over the fruit fly area, and fit it into the base. This is the spider area. Slice a little trap door into which you can place a spider (and then tape it closed).

    Diagram: remainder of bottle 1 fit over bottles from 5
Diagram: control chamber 1

Make a total of four chambers. Vary the four chambers as follows:

  • Chamber 1, the control chamber, includes a spider, fruit, and access for fruit flies to enter (two small holes cut into the feet of bottle #2).

  • Chamber 2 contains a spider and access for fruit flies, but no fruit.

  • Chamber 3 contains a spider and fruit but no access for fruit flies.

  • Chamber 4 contains fruit and access for fruit flies, but no spider.