Worm World Activity
& Relationship to Wisconsin's Model Academic Standards for Science and Environmental Education
(adaptations for specific grade levels are outlined throughout)
Students ask questions about different habitats. Students raise earthworms to the soil surface by using a non-lethal irritant (dry mustard slurry!), then count and compare data.
What is "good" earthworm habitat and how might we improve an area for these humble creatures? Despite their small size and inconspicuous colors, earthworms in large numbers can be a major force below ground. As mentioned above, earthworms can move a huge amount of soil each year! Also, earthworms create large pores in the soil that allow for essential aeration.
To study earthworms and their habitats, you have to find them! You can dig them up, but that destroys their habitat. Instead, you can force them to come to the surface. In this activity, adapted from NAAEE’s Worm Worlds, students use a "slurry" made of dry mustard—an irritant that bothers worms a little but doesn’t harm them—to sample earthworms. Teams count all the worms they find (both adults and juveniles) to get an idea of what might be good or bad worm habitat.
This activity can be much more than a simple counting activity. Rather, students can ask meaningful ecological questions: What environmental factors determine how many earthworms are found in different habitats? This question can be answered through further inferences, educated guesses, and observations, with the depth of the research depending on the students’ level. Some factors that may influence earthworms are the density and moisture level of the soil, the kind and type of organic matter the soil contains, whether there are transplanted trees nearby whose rootballs might have carried worms to the site, and the presence of animals that eat worms.
For each team of researchers (usually 2-3 students per team, depending upon background and age):
- 1. Quarter Square Meter (0.25m2) Quadrat
- 2. Mustard Slurry Jugs with 1 sprinkler head
- Use gallon milk jugs or watering cans
- Mustard Slurry Recipe: 2 T dry mustard powder per gallon of water. Shake vigorously. (Try Colman’s or bulk mustard from organic grocer—it must be fresh). This makes a 0.33% solution of mustard by weight. Higher concentrations might harm the worms.
- 3. Bowl or pan (for holding worms
- 4. Scissors or clippers (for clipping grass to see worms better)
- 5. Pencil, data sheet, and clipboard
For the whole group:
Extra jug with about ½ gallon of water (for wetting bowls and rinsing worms)