SWBAT explore how to create composite shapes out of 3D figures.

Students think critically about how 3D shapes fit together in different ways to create strong structures that stand up.

5 minutes

**CCSS Context:**

This lesson is aligned to 1GA2, which asks students to build composite 3D shapes. Students work to use concrete models (incredibly important in first grade) to build shapes, but then also transition to the abstract as they try to create concrete composite models that match a picture. Students also have to create conjectures about composite shapes that stand up versus composite shapes that fall down.

**Review**:

We have looked at the attributes of 3D shapes and thought about the rules we have for each shape. Today we are going to look at how these shapes fit together.

**Connect:**

Mathematicians use 3D shapes together to make larger, composite shapes. However, we have to pay close attention to the features to put together shapes that will stand.

**Objective:**

Your job today is to build 4 buildings for Santa’s workshops. Your thinking job is: Why do these shapes fit together? Why doesn’t this shape fall down?

10 minutes

We are going to be using our geoblocks to build different structures. Before we do that, though, we need to think about what we know about these shapes to see if we can figure out how they would fit together. We are going to be building buildings for Santa’s workshop. We have to make sure they will stand up!

**1. I'll present a sphere and cube.**

- Partner talk: Would these be good shapes to use to make a building for Santa? Why or why not?

- Partner talk: Could you use these two shapes to make a building? Why or why not? How would you have to orient these shapes so they would stand up?

**3. Replace the cube with a cone. **Partner talk: Could you use these shapes to make a building? How?

**Big takeaway question: What makes these shapes fit together? **

This question focuses students on MP7, Look for and make use of structure. This part of the lesson is asking kids to see a pattern across all three shape compositions they have observed. Hopefully they have noticed that the only way shapes can truly stand up is if they both have faces.

20 minutes

**Student Work Time: **

Students all look at Shape A from the Investigations sheet. You can go here to get the master copy.

Students write down the building materials needed to make this building and then build it. If they finish, they write why this building doesn’t fall over.

**Students come back together: **I’ll have a model of the building on the rug for the discussion.

Guiding Questions:

- How did you build this shape?
- Partner talk: How could I rearrange these shapes so I could make a different building that would also stand up?

Teacher models one of the ways students discussed. Why does the building still stand up?

Partner talk: How could I rearrange these shapes so the building would fall?

Model a few ideas. After each structure falls, ask: What about this arrangement meant the building wasn’t stable?

15 minutes

**Students tackle building one of the buildings from Santa's Workshop! I'll explain that they are writing their plans so they can send them to the elves. **

The idea behind the independent practice is that students pick the exact shape to create the structure and make it look just like the building. The reasoning behind this is that students are transferring how shapes are represented in pictures to their real life counterparts.

Find the shapes I used here.

Directions:

1. Choose 1 shape to create.

2. Record which shape (Building A, B, C or D) on your recording sheet. **See attached recording sheet!**

3. Students write down what shapes they used under "Building Materials" and draw the building.

4. Students reorganize their shapes to show another way you could build this building and it would still stand up. They record a drawing of the plan.

5. Students reorganize their shapes so the building will fall down!

Watch the attached Student Teacher Dialogue video to listen into student-teacher dialogue. This student was struggling to make a composite shape that looks just like the model.

10 minutes

Students write a letter to Santa about the building they made. Students are expected to use the shape names and they can use direction words to help explain how to build it. This is aligned to the CCSS emphasis on writing across the curriculum.

Before students write their own letters, I'll quickly model the kind of words they might use in their own explanations such as...

- Sequencing words (first, next, last)
- Positional words (on top, below, beside, to the right, etc)

**Here's the letter: Santa Letter.pdf**

25 minutes

Assess student understanding of 1.G.A1, 1.GA2, 1.OA.1, and 1.OA.C6 in the attached Shapes Assessment.pdf!

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