Wander With Water Snails- Water Snails Structure

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Objective

Students will identify the major parts of a fresh water snail and communicate this with a diagram.

Big Idea

What body parts does a water snail use to survive?

Hook

5 minutes

I ring my chime to get the class’s attention.  I ask them to return to the carpet squares and ‘Show Five’.  Once seated, I announce that we were about to begin the study on our second kind of snail. I share “The three type of water animal that we studied in this unit were………..”  I wait for answers from the class.  As expected, they answer “Guppies!  Goldfish.  Tadpoles.”.  I continue,  “We observed them and noticed there are some important ways they are different from each other.  Is there another water animal that lives in our class? “  I set a timer and announce, “You have one minute to walk backwards around the class and look for this other water animal.”  I want to give them an opportunity to identify the water snail on their own.  Rather than watching them run around, I include the “backward” part of the direction because it helps them slow down.  After one minute, I ring the chime to bring them back to their carpet squares.  

Large Group Instruction

20 minutes

I ask for their observations, “What animals that live in water did you see in our class?”. “Fish”, “Snails in the fish tank”.  “Today, we get to learn more about those water snails in the fish tank.”  I show them a detailed image from the internet.  My goal is to help the students focus the unique features of this snail so they could see characteristics that were different from the land snail (a more in depth compare/contrast will come in a later lesson).  Since they already studied the basic body of a snail, they had some background knowledge that could immediately be applied.

I draw a KWL chart about water snails and ask “Based on some observations and experience with the land snails, what do we know about water snails?”.  I record the responses- “They crawl the same”  “They have shells”.  Then I ask, “What do we think will be different?  What do we want to learn?”.  I add the question about ‘different’ as a jumping off point to the ‘want to know’.  Otherwise, it can be difficult to get them to come up with questions that reflect real wonder and deeper level thinking.

To keep the attention on the material in one place, I model how to quick draw an aquatic snail on the bottom of the KWL chart.  While I am drawing, I tell the students the names for the structures they have observed. “Most of the parts of the water snail are same as the land snail.  Can you help me label them?”  As I draw lines to the location of foot, shell, mouth, and tentacles, I explain that naturalists label their drawings so they can remember what they learned about the animals they observed.  I call on for volunteers to come up and identify each part before I label it.  While I call them 'volunteers', I often will strategically choose certain students who need extra practice in oral communication and presentation.  As long as you don't do what I call 'cherry pick' (e.g. always choose the high learners), this is a good strategy to spread the wealth and give everyone an opportunity to speak in front of their peers.  

I then introduce two differences. “One part that a land snail does not have is something called an operculum.  It’s on the bottom of the foot and looks like an oval trap door.  It allows the sea snail close off it’s inside so it protects the moisture and doesn’t dry out. The water snail also does not have the lower tentacles.  Does anyone have any idea why?”  I wondered if anyone would make a connection to the ‘hearing’ function we learned about for the Land Snail.  When no answers came, I said, “The water snails don’t have any need to hear, so they use their one set of tentacles to ‘see’- feel their way around their environment.”.

Small Group Instruction

10 minutes

After we finished the whole class anatomy and quick draw activity, I told them “It’s time to be Naturalists.  We’re going to continue this lesson with your table groups.  I need you to record your own version of a water snail.”.  I used the chime to dismiss the students back to their tables.  Once they were seated, I said “Remember a few unique aspects of the water snail.  Think about shape, features, and color..or anything else you and your group remember.” To extend their observation experience and help with the drawing, I put out a small container with a few water snails on each table, as well as a picture.  I also invited the students to observe the water snails in our tanks.  

I passed out half sheets of paper for their drawing, with a simple label of “Water Snail”.  I announced they had about ten minutes to come up their record (tracking the passage of time can be difficult at this age.  To help this along, I use a ‘Time Timer’ to give a visual representation of this concept.). Since we had studied the two snails for a few lessons, the class had an adequate knowledge base so this independent activity could act as a summative assessment.

After five minutes, I gave them a three-minute warning with the chime.  Once they completed their drawing, they had another minute to have a brief discussion at their table to share ideas.  As that wound down, I again rang the chime.  I asked the students to bring their drawing when they return to their carpet squares to talk about our lesson and share their observations.

 

 

Wrap Up

5 minutes

I asked the class to share their ideas, “Who noticed something that was different in this snail?” (“No tentacles near the mouth”  “The shell was smaller and pointier than the land snail.”.  As each idea was shared, I added it to the KWL chart under 'learned'.  After all ideas were recorded, we reviewed the contributions before it was posted near the Science area so the students could refer to it during future Science lessons or drawing/writing activities.  I dismissed students by table group to put away their drawings and return to their carpet squares.