Snail Observation Exercise
Author: Matt Wedel
Overview: In this exercise, each student is given a pond snail in a clear glass and asked to make observations on the snail’s form and behavior. One of the key ideas is that seemingly common subjects (like snails) often have surprising or interesting properties, if only we take the time to look carefully.
California Science Education Standards:
Grade span: 6-8 or 9-12
Advanced preparation: None.
Time: 30 minutes.
Grouping: The students are encouraged to work on their own (provided you have enough snails).
Give each student a glass with a little water and a snail, a blank piece of paper, and a hand lens. Have them fold their papers in thirds, as when folding a letter, and then turn the pages sideways so that the folds form three columns. In the left-hand column, ask the students to write down their observations on the snails’ form—size, shape, color, texture, and so on. In the middle column, ask them to write down their observations on the snails’ behavior—does it move? If so, how? Does it travel in a straight line? A curving, twisted path? A circle? Where does the snail go in the glass—does it stay on the bottom, or climb the sides, or even swim upside down across the surface of the water? Ask the students to pick up their glasses and observe the snails’ broad, muscular foot. They may be able to see the mouth opening and closing near the front of the foot. Finally, ask the students to draw their snails in the right hand column of their papers. Remind them that sketches complement written observations, and don't have to be artistic to convey useful information (such as whether their snails are spotted or striped).
You may ask the students to place a drop of water on the palm of one hand and then set their snails on their hands. Don’t be surprised if some students are too squeamish.
Finally, if time allows, ask the students to trade snails with a neighbor, and then make lists of the similarities and the differences between the two snails.
After the exercise is over, you’ll have some snails to deal with. If you got your snails from a pet store, don’t release them into the wild. They can serve as vectors for foreign disease organisms and contaminate native fish populations. I feed leftover snails to my turtle. If you don’t know any turtle enthusiasts, you might try freezing the snails before disposing of them.