Handbook of Nature-Study · Lesson CX · Topic 18: Daddy-longlegs and spiders
110. Cobwebs
Goal: Your child can describe a tangled cobweb and how the house spider uses it, and count a spider's legs and body parts.
You'll need
- A cobweb in a corner of a room, preferably with a spider
- A flashlight
- A hand lens (magnifying glass)
- A nature notebook and a pencil (colored pencils if you have them)
What's in the book
Comstock's introduction to spiders as "the civil engineers among the small inhabitants of our fields and woods," builders of bridges, nets and balloons, and useful insect-eaters. Then Lesson CX's leading thought, method and six questions, and a poem.
The lesson, step by step
When and where
Any season, indoors. Comstock's method: "The pupils should have under observation a cobweb in a corner of a room, preferably with a spider in it." Choose a web you can see clearly in a well-lit room.
Safety first
Spider safety: never pick up a spider you don't know. Look with a hand lens from a few inches away, touch webs only with a grass stem or a pencil, and never reach into a dark corner, woodpile or shed where you can't see.
The black widow is also a cobweb spider: shiny black, often with a red hourglass underneath. It lives in garages, sheds, woodpiles and outdoor furniture. Look only at webs in clear, open corners of the house.
Comstock asks children to put a spider under a tumbler. Instead, look at it with the lens where it sits, or use the book's pictures.
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 cobwebs which are found in the corners of ceilings and in other dark places in our houses, are made by the house spider which spins its web in these situations for the purpose of catching insects.
The web
Shine the flashlight across the web from the side so the threads show.
Is the web in a sheet or is it a mass of crisscrossed, tangled threads? How are the threads held in place?
What is the purpose of this web? Where does the spider hide?
The spider at work
If a fly becomes tangled in a web, describe the action of the spider.
If the spider is frightened, what does it do? Where does the silken thread come from, and how does its source differ from the source of the silken thread spun by caterpillars?
A spider spins from the tip of its abdomen; a caterpillar spins from near its mouth.
Count and compare
How many legs has it? How does the spider differ from insects in this respect? How many sections are there to the body?
Can you see the palpi on each side of the jaws? Where are the spider's eyes? How many pairs has it?
Then read the leading thought aloud.
Nature notebook
Draw a spider and an insect side by side: the spider with two body parts and eight legs, the insect with three body parts, six legs and antennæ. Label the differences.