A Disappearing Act
If you were a worm trying to escape a hungry bird, what would your luck
depend upon? Would the soil type make any difference? In this activity,
students use worms to investigate how long it take a worm to get underground
in various soil types, and to consider variables that might affect the
time it takes.
where students have seen earthworms, and to comment on what the soil
was like. (Depending upon age of your students, you may wish to discuss
that soil is make of particles of sand, silt, and clay. Clay soil
is very fine. Sandy soil has larger particles and feels gritty. Loam
soil is a mixture of sand, clay, and organic matter--once-living leaves,
twigs, stems, and parts of animals and plants. Loam is usually black.)
teams of students to collect soil from each of these places: a garden,
a field, an empy lot, woods, and any other places they have observed
students to make predictions about which bucket worms will burrow
and disappear the fastest and which bucket the slowest. What are the
reasons for these predictions?
our data collection sheet
and ask students to time and record the worms's burrowing into the
soil of each bucket.
predictions. Ask students to brainstorm a list of variables that might
affect the time it takes for a worm to disappear underground. (The
ideas may include things such as soil type, worm type, moisture, compaction
of soil, etc.)
How could you find out how each of the variables affects the time
it takes for the worm to go underground?
This! Journaling Question
would it take longer for a worm to escape a woodcock than to escape
a robin? (HINT: Look at the beaks of these two birds.)
Predators: American Woodcock and American Robin
(photos by J.A.Spendelow (l) and Ann