Handbook of Nature-Study · Lesson CVII · Topic 17: Snail, earthworm and crayfish
107. The earthworm
Goal: Your child can describe how an earthworm moves, feels and feeds, and explain how worms plow and enrich the soil.
You'll need
- A garden spade and a patch of garden soil
- A tray, damp paper towels and a spray bottle
- A flashlight
- A ruler
- A hand lens (magnifying glass)
- A nature notebook and a pencil (colored pencils if you have them)
What's in the book
Comstock's story of the earthworm as a farmer: long before people tilled the soil, worms were plowing, harrowing and fertilizing it, drawing leaves into their burrows and leaving their "casts" on the surface. Then Lesson CVII's leading thought, method and questions.
The lesson, step by step
When and where
Spring and fall, when the soil is moist. Dig in the garden, or look on paths after a rain. Comstock's method: "They are nocturnal workers and may be observed by lantern light." A flashlight walk on a damp night works well.
Be kind to worms
Wet your hands before you pick up a worm, keep worms on damp paper towels out of the sun, and put them back in the soil after fifteen minutes or so. Wash hands with soap and water afterward.
Keep the big idea in mind
Comstock's "leading thought" is the one idea the lesson is meant to lead to. Read it to yourself now, and save it to share at the end, after your child has looked and answered:
The earthworm is a creature of the soil and is of much economic importance.
Economic importance means it matters to farmers and gardeners.
How it moves
Put a worm on the damp tray.
How does the earthworm crawl? How does it turn over? Has it legs? Compare its movement with that of a snake, another legless animal. What special provision for locomotion has the earthworm?
Compare the lengths of the contracted and extended body.
Stroke it very gently from tail to head with a fingertip, then from head to tail: you may feel the tiny bristles that grip the soil.
Its body and senses
Describe the body—its shape and color, above and below. Examine the segments. Do all the worms have the same number? Compare the head end with the tail end of the body. Has every worm a "saddle," or clitellum?
Does the earthworm hear easily? Has it eyes? Is it sensible to smell or to touch? What sense is most strongly developed?
Shade half the tray with your hand and see which way the worm goes.
The night's work
Try Comstock's experiment:
To form some estimate of the work done in a single night, remove the "casts" from a square yard of earth one day, and examine that piece of earth the next.
What is the food of the earthworm? How does it get its food?
Look for leaves pulled partly down into burrows.
Nature notebook
Draw an earthworm, label the head end, the saddle and the tail, and write how long it was stretched out and pulled in. Record how many casts appeared on your square yard overnight. Read the leading thought aloud.
Tip
What we know now: many of the earthworms in North American gardens came from Europe long ago. In some northern forests that had no earthworms, they are changing the forest floor, so never dump leftover fishing worms in the woods.