Structures of Life
Investigation 4: Meet the Land Snail
The Snail Pull
Students attach loads to snails and discover how much mass a snail can pull; they then compare that load to the mass of the snail itself.
1.3.L. Describe how an organism's behavior and ability to survive is influenced by its environment, other life forms, and availability of food and/or other resources.
2.1.5 Record and report observations, explanations, and conclusions using oral and written expression.
3.1.1 Understand that all scientific observations should be reported accurately even when they contradict expectations.
The structures of animals have particular functions that help the animal survive.
The shell of the land snail helps protect it during dry conditions.
The soft, moist foot of a land snail allows it to move and stick to a variety of surfaces.
1. Make sure snail shells are dry before attaching thread. Duct tape works best for keeping the thread attached.
2. Placing all snails on a large table or two large tables make it more fun to watch.
3. Placing carrots in front of snails can help with the snail pull. We call it a "race" to make it more exciting.
4. Keep the water bottle handy because spraying a snail lightly can help it move and make it a little more exciting.
5. As the snails move, add more washers to see how strong each snail is. You will be surprised that 6 or 7 washers will not affect the movement of the larger snails.
6. During this lesson is a good time to let small groups go and measure their plants and observe the crayfish.
A snail pulling a washer on its own. Add more washers as the snail moves across the table.
If the snail won't move, try spraying it with water or place a carrot in front of the snail. Keep moving the carrot away as the snail approaches it.
1. Keep all materials at the station at which the students are working. Let the students go to each workstation and explore.
2. Set rules and guidelines for observing the animals during non-science times.
3. Keep Moving! If you are constantly moving, it will keep everyone on task.
4. Watch for the child who may want to experiment with the snail and hurt it.
5. If you are not paying attention, snails may go to the edge of a table and end up dangling. Make sure that students don't attempt to place the snail in the hanging position.
1. You can lengthen or shorten the time on any lesson.
2. Use pages 2 & 3 to help guide further inquiry at the end of every part.
3. If students are afraid of touching crayfish, use 2 plastic spoons to scoop them up to place into the basins. If they are afraid of touching the snails, use plastic gloves.
4. Give students time to discuss their observations with each other.
5. Keep word banks and content inquiry charts up so students can see and have more time to copy later, if needed. It's nice if you can keep them up all the time and just add to them as you go.
6. Remember that you are now observing the plants, crayfish and snails. Set up a schedule that won't require a lot of class time.
1. Have students reflect on the day's lesson in their journal.
2. Start and finish each lesson with a KWLQ chart. ("What do I know?" "What do I want to know?" "What have I learned?" and "Are there any more questions to investigate?")
3. Have students write all word banks and inquiries in their journals.
Read FOSS's Science story A Chance Encounter.
Check the Resources section of the teacher's guide for more reading suggestions, or the literature link on this site.