Worms!!!_
Grade Level: K-3, can be modified for grades 4-8.
Standards:
Science - NGSS
Practice 5: Using mathematical and computational thinking.
LS2.A: Interdependent Relationships in Ecosystems
Math – CCSS
2.MD.D.9: Generate measurement data by measuring lengths of several objects to the nearest whole unit, or by making
repeated measurements of the same object. Show the measurements by making a line plot, where the horizontal scale is
marked off in whole-number units.
2.MD.D.10: Draw a picture graph and a bar graph (with single-unit scale) to represent a data set with up to four
categories. Solve simple put-together, take-apart, and compare problems1 using information presented in a bar graph.
What is an earthworm?
Where do earthworms live?
What do earthworms eat?
Engage your students in the world of worms that live right under their feet! In this activity children are allowed
to dig in the dirt and touch worms while learning important science skills such as collecting data, making
observations, making comparisons, and drawing conclusions. Ideal for a variety of schoolyards (gardens,
flower bed, wooded area, lawn, anywhere you can safely dig in the soil!)
Background:
Of all the members of the soil food web, earthworms are probably the most familiar. Most of you become
familiar with these soft, slimy, invertebrates at a young age. Earthworms are major decomposers of dead and
decomposing organic matter. They obtain their nutrition from the bacteria and fungi that grow upon these
materials. Earthworms also break up the organic matter and play a major role in recycling the nutrients
contained in organic matter.
What do Worms Do?
Earthworms dramatically affect soil structure, water movement, nutrient cycling, and plant growth. They are not
essential to have in the soil, but their presence can be an indicator of good soil quality. Earthworms perform
several beneficial functions:
Decomposition and nutrient release. Earthworms break up larger plant organic matter by their feeding
activities.
Mixing and castings. Earthworms feed on plant litter as well as a wide range of decaying organic substances.
Earthworm casts are excreted masses of mineral soil often mixed with smaller bits of digested plant residues.
The earthworm activities of eating, burrowing, mixing, and casting all act to form soil aggregates, aerate the
soil, and improve soil water infiltration and holding capacity that improve soil habitat structure.
Increased air and water infiltration. Earthworms improve the amount of air that is contained in the soil
(aeration) by their burrowing activity and at the same time they improve soil porosity by improving the overall
structure of the soil as a habitat for themselves and other soil organisms. This means that soils with earthworms
not only contain more air but also fill and drain water faster.
Provide channels for root growth. The channels made by deep-burrowing earthworms are lined with readily
available nutrients. This makes it easier for roots to penetrate deep into the soil and for food to be available for
plants to grow.
Adapted from http://www.naturewatch.ca/english/wormwatch/programs/introduction.html
Activity:
(from Earth Partnership for School‟s “Alien Invaders of Wisconsin” lesson):
Materials:
 Metal frame for sampling, 33cm x 33 cm square and about 6” high (or mark off a similar area as best
you can using other materials)
 Concentrated mustard powder
 Measuring cup
 Water
 Empty gallon jugs
 „Earthworms of the Great Lakes‟ identification guides
 Jars for collecting worms
 Watch or timer
 Data sheets
What to do:
Have students work in teams of 3-4 students (make sure that the group contains at least 3 teams so that there are
enough replicates). Each team will add 1/3 cup of mustard powder to their jug and then fill it up with water.
Shake the jug vigorously to mix!
Clear the leaf litter layer away (just using your hands or feet is fine). Set the metal frame down onto ground,
making it as level as possible and pressing it into the soil so that it forms a barrier. You may want to examine
the soil in your area first: can you see a duff layer, or is there a layer of black topsoil on the surface? Pour about
half the gallon of mustard mix into the frame. Wait about 3 min. before pouring the rest of the gallon in.
Meanwhile, everyone should watch for worms! Wait until the worms are at least halfway out before you try to
pick them up, or you may scare them back into the ground! Carefully dip worms in a shallow bowl of water to
rinse the dry mustard off their bodies. Place worms in the glass jar so you can get a good count and try to
identify them.
Have students complete the Worm Watchers Data Sheet.
The main goal is to count how many worms were present, and break down that number into juveniles versus
adults (the identification guide helps with this—the main difference is that adults have a saddle-shaped
reproductive organ called a clitellum). Try to classify worms into ecological groups based on their size and
color (litter dwellers, soil dwellers, and deep burrowers—see Worm Watchers for more info). Graph the results.
Discussion Questions:
1. What are the benefits of worms? (students may need to research worms using books, interviews with
gardeners, and the internet)
2. Do we want worms in our garden (prairie, school lawn, etc)? Why or why not?
Resources:
Cronin, Doreen. Diary of a Worm. (Written from a worm‟s perspective, a great story for grades K-2.)
Great Lakes WormWatch:
http://www.nrri.umn.edu/worms/
Worm Watch:
http://www.naturewatch.ca/english/wormwatch/programs/introduction.html