Earthworm Structure- Inside Out!
Lesson 2 of 3
Objective: Students will create a model to identify the parts of an earthworm.
I ring my chime to get the class’s attention. I announce we were about to begin our next Science lesson about earthworms. I ask them to return to the carpet squares and ‘Show Five’.
In my hand, I have a small Slinky. As I played with it, I wondered out loud “Hmmm..this reminds me of an animal…Does anyone have an idea?” “Worm?” “What makes you think that?” “It’s stretchy and bendy?” “Let’s look at that idea a little closer.”
Large Group Instruction
I ask the class, “With all our recent rain, how many of you have seen an earthworm outside today?” I wait for answers from the class. As expected, they answer “Me!”. I continue, “Were they different..or were they all the same?” These were designed to be quick questions so it's OK that I didn't get many answers. I know the instruction will soon come and I want to use the immediacy of their outside experience to give them a concrete connection to the upcoming material.
We then watch a short clip showing just how the earthworm's structure helps it move so they better knew the details of what they were observing in the earthworms they collected. Here are some additional facts about earthworms that enhanced their observation.
• Earthworms are boneless.: “Feel your finger. Now imagine your finger is one big muscle. No bones to keep it straight or protected. Earthworms are one big muscle whose purpose is to dig underground. It moves in a way similar to the snails we studied whose body is one big muscle, the body part that makes things move."
• They move using a pattern of rings.: "Their structure is kind of like a Slinky because it’s the kind of animal made up of muscle rings that help it move. An earthworm (or red worm) is the type we most often see. When we watch it move, you see the contraction of these muscles, almost like they’re moving against each other- contract release, contract release” “That’s a pattern!” “You are absolutely right! Since the worm has no brain, that pattern gives the worm the ability to move by instinct, finding the best places to survive."
• Their digestive system adds valuable nutrients to the soil: "This ability to dig makes it useful when it looks for food, plus the digging loosens up the soil and makes it easier for plants to grow. After they dig and eat, their poop is left in a cast- like a trail hole- to add valuable nutrients to the soil.” "Ewww!" "Yeah, I know. Poop can be 'Eww!'. But worm poop helps the ground in a very not 'Eww!' way!"
I display three earthworm pictures on the easel board. I then pass them around the circle so the students could examine the images further. Extra review and examination time will help them on the assessment piece of the lesson. As they look, I tell them, “See the different earthworms? What do you notice? How are they different?” and wait for answers. As expected, the children first notice the color, “Red” “White” “Pink”. "What else did you notice?” “Small rings” “Pointy tails” “A belt” “Very observant. Based on what we just learned from the pictures- and even from the Slinky- how do these rings and body shape help the earthworm?” “They help them move.”. To avoid having them sit too long, I continue the instruction at their table.
Small Group Instruction
• Playdough (or a similar material), dark pink
• Plastic combs (one per group)
I ring the chime to get the students’ attention. "It’s time to show each other what we just learned.” and I have them move to their tables to begin the activity.
As they sit in their seats, I pass out playdough that I previously divided into individual portions. I want to keep this activity simple so the students could quickly practice the idea. “Your job is to create an earthworm with the kind of body that can survive in their habitat. What can you add to make it look like an earthworm? “Rings?” “Absolutely right! You can add rings to show the muscle that makes it move. What else?” “A long skinny worm body?” “That, too. It will help them find room to dig.” I give some instructions:
1. "Roll the playdough out to create the correct earthworm shape. Look at the earthworms in the containers on their tables if you need."
2. "Create some rings to show the structure that helps the worms move." As the students begin to work, I then pass out some inexpensive Dollar Store 10 for $1 combs to help make the pattern that would create the rings. I briefly stop at each table to model how to make the rings by gently dragging or pressing the comb over the surface of the play dough and rolling it a little. The intent is to have the worm look realistic enough so they could be used to explain the earthworm structure to someone else.
3. "Share the reasons why you're making the worm look this way with a partner." I ask them to use sentence starters like ‘I put the rings because ______’ or ‘The earthworm is skinny so it can ________.’ to practice the Science vocabulary and explain their reasoning.
As they finish up, I circulate around to help, when necessary, students adjust the structure or clarify their thinking.
This activity could go quickly..or last until the students get tired to creating play dough earthworms. I aim for something in between. Rather than rush through it, I feel an extended creation period may prompt some extra questions and additional realizations. Once they all complete their earthworms and the peer comments began to wind down, I pass out plastic baggies to store their creations and take them home. Yes, they’ll probably get squished, though now they know how to recreate it. I get their attention with the chime and ask them to put away their baggies before they come back to the carpets.
When we were seated, I do a review with the whole group so we could learn from each other. I asked, “How did creating a playdough worm help you better understand the structure of an earthworm?” “We rolled it out to look just like a real earthworm.” “We made lines so they could pretend move.”. I let them continue to share for a few minutes and wrapped it up. “This activity should help us understand an earthworm better. How many of you will look at them differently now?” “Me!!” Sounds like we have a new room of worm stewards!