SWBAT explore how 2D shape faces create composite 3D shapes.

Students tackle a complex task and build understanding of how faces fit together to create 3D shapes, all while helping Santa!

5 minutes

For this lesson, you'll need enough cardboard boxes so each pair of students can have one. I unfolded all of the boxes, and then cut some of the pieces apart. Each pair of students will receive one disassembled box to put together.

This task is very complex, which is aligned to CCSS vision of complex tasks. By tackling the challenge of reassembling a box, students are having to apply what they know about 3D shapes to think about how all of the faces fit together to create the full shape.

**Review**:

We have been working on the academic vocabulary we need to describe these 3D shapes. Today we are going to investigate the key features of some of the 3D shapes.

**Connect**:

A 3D shape is like a 3D movie-it pops out! But today we are looking at how one can create a 3D shape out of our flat shapes.

**Objective**:

How can I use flat shapes to create a composite 3D shape?

10 minutes

I'll quickly present a situation to students that grounds this in a "real life" situation. Common Core pushes real world applications of problem solving. In first grade, this Santa-themed problem is about as real life as it gets!

**Present problem: Santa called me and asked for our help! The elves are trying to box up all the toys but they are running out of time and don't have time to put together the boxes. Our job is to use what we know about 2D faces to help the elves put the rectangular prism back together!**

I'll quickly show an example box but I won't model putting it together! I am merely setting up expectations for their partner work time (see reflection video) and showing them the pieces they will be working with.

25 minutes

This portion of the lesson is longer because I am giving students al lot of trial and error time. Students are given their boxes with a partner, a roll of tape and a marker.

If students finish their boxes early, they will get time to label the shapes of the faces on the box.

While students are working, I am floating around the room, reinforcing expectations and asking some guiding questions. This portion of the lesson is aligned to MP3-Construct viable arguments and critique the reasoning of others. Students are having to discuss with each other how to put the box together, and evaluate whether or not their partner's idea makes sense.

Expect that some students, even some students who tend to excel in number sense, may struggle with this activity!

**If students are successfully putting the box together... **

- How did you know to put those shapes together?
- What shapes are the faces so far?

**If students are struggling to put the box together...**

- Think of a rectangular prism, what do you know about its faces?
- I'll choose 2 pieces and ask: How could you fit these together? What edges would match?
- Are there pieces that are working together? How did you know those would fit together?

**See attached video of students tackling this difficult task of putting the boxes together!**

15 minutes

Now students are going to match some 3D shapes to their matching "footprint" or "faces". This helps them think about the 2D shapes that make up other solid shapes.

**Each child receives a Footprint master and a bag of geoblocks. You can go here to get the footprint master!**

Directions:

1. Find a geoblock that fits completely into the face shape.

2. Label the footprint with what geoblock fit there (triangular prism, cube, etc).

3. Work to fill all of the footprints. If you finish, try to find what 2 shapes could fit together to also create that footprint.

5 minutes

Students come back together and share their work with a partner, focusing in on what flat face each 3D shape had.

After students share, they play a quick online game on the promethean board: Shape Shoot Math Game Link