Are You My Mommy?- Life Cycle of a Water Snail

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Student will identify the major stages of a water snail life cycle and record with a visual sample.

Big Idea

How does a water snail survive in the water to grow from egg to adult snail?


5 minutes

Bubbles are an infinitely engaging activity.  Since a teacher's purpose is to be creative with the things we have, I decide to use this interest to my advantage with my lesson introduction.  

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 continue our study on the water snail.  I sit on the floor with them and get out a bottle of bubbles.  As I begin to blow bubbles over the students,  I asked “Look at the bubbles.  Who has noticed things that look like bubbles in the fish tank?”   I wait for answers from the class.  As expected, they answer “Me!”.  "But..are they really bubbles?  Let's find out!" 

Whole Group Instruction

15 minutes

I begin my lesson introduction by asking,  “How many of you have looked at the snails in our fish tank?"  Most hands went up.  “When you saw the bubbles, did you think anything special?” “Noooo…”  “So when you see things like this, how do you know if they are really bubbles?”  “They are round and tiny.”  “They float around.”.  I give them a moment to consider the idea that things aren't always what them seem and then ask “What if they looked like a bubble but were really something else?”

I continue the instruction, “When snails are first born, they begin as tiny round eggs.  The outside of the egg is not hard like a chicken egg.  The outside of a snail egg is kind if opaque.  That means it's kind of see through but not really clear like glass.  And it’s very yielding, like Jello.  This becomes a kind of cushion that protects the new egg.  It kind of looks like a...bubble!"  I want to make this information concrete by connecting snail eggs to something familiar as well as add words like ‘opaque’ and ‘yielding’ to grow their vocabulary.  It's very easy for students at this age, particularly English Learners, to use colloquial or familiar vocabulary in their communication.  Research supports the benefit of raising vocabulary so I like to connect new words to our curriculum in a fun way, using 'paint chips' to give a visual representation of how academic vocabulary words can grow from something more simple.  

As I continue my description of the snail development, I begin to pass around the pictures of the stages of snail life cycle so the students can see the process in action.  As I introduce each snail stage, I list it on a chart and add a simple illustration to revisit later in the Wrap Up.  “You can see here the egg starts out kind of clear.  As soon as the shell begins to develop, next you'll see a tiny black dot called a hatchling begin to appear in the center of the egg.  It’s surrounded by more clear material.  It’s like the albumen in a chicken egg and serves to nourish the development of the snail.  Then, as the snail continues to grow, both the snail and shell gets bigger.  The soft outside covering and clear fluid go away and the snail parts begin to take its place.  Last, when it becomes mature, the water snail will be better protected from predators with the complete body structure of a shell, foot, one set of tentacles, and an operculum- parts we studied earlier this week.”.  Since the purpose of this lesson is the stages of a water snail development, I verbally review the structure vocabulary here before I move on.

Individual Instruction

15 minutes

After the whole class finish their observations, I tell them “It’s time to continue this lesson at your table.  We will take pictures of the snail’s life cycle that we just saw and put them in order.”.  To maintain consistency, I use the same pictures that I used in the Whole Group section to create the Life Cycle worksheet.

I use the chime to dismiss the students back to their tables. Once they were seated, I say “Before you start, let’s review the stages of the snail’s development.  First, it's an… "Egg!”  "Next, it becomes.." “a tiny dot”  "'hatchling", I correct them-though pretty close!, "then it's a…" "Baby snail”, "last it becomes a "Mature snail”.  "OK, sounds like you're ready.”.  There are times when I pass out a paper and have the students read it along to give a visual to the vocabulary.  Since we had already done this on the carpet squares, I skip this step.

To make sure the process was clear, I go over the directions before I pass out the worksheets so students wouldn’t start work before they understand what to do.  “First, you need to review the vocabulary words to yourself," I count them off on my fingers "Egg, hatchling, baby snail, and mature snail.  Next, cut out the small pictures of the snail life cycle.  Then, match the pictures to the correct box.  Last, glue the pictures to the box on the paper only after you are confident that the pictures match the correct label.”  They have a tendency to immediately use glue, without checking for mistakes first, so I included the last step to avoid changing pictures and ripped papers.  I remind them about our rule for glue, “Use only a dot of glue, no bigger than the fingernail on your pinkie.”  I chose this comparison years ago both to give an instant reference and save on glue!  Then I pass out the Snail Life Cycle worksheets.  While they work, I circulate and check in on their progress.

As expected, the simple activity goes pretty quickly.  After five minutes, I see that most students are finished so I give them a one-minute warning with the chime.  As the rest complete their worksheet, they have another minute to have a brief discussion at their table to share and discuss the vocabulary.  As those discussions wind down, I again ring the chime.  I ask the students to bring their paper when they return to their carpet squares to talk about our lesson and add their ideas to our vocabulary chart.

Wrap Up

5 minutes

As we sit down, I make a quick connection to how a baby survives in a protected environment before it’s born.  Then I ask the class to share their ideas, “Who noticed a connection between the snail life cycle and how it survives?" It’s protected in it’s bubble.”  “It doesn’t need to breath.” “The hard shell keeps it from ‘predtors’.”.  As each idea (bubble, breathe, shell) was shared, I add it to the chart.  After all ideas are recorded, we review 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.