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* *Reflection: Checks for Understanding
Attributes of 3D Shapes Part 2 - Section 2: Teaching the Lesson

Students were asked to count the various parts of the 3 shapes they had made. I assumed that remembering which part was which might be a bit confusing and was ready to provide support to the students for this process. We did the first shape together. We reviewed the terms. I felt that I had laid the groundwork in the past few days for identifying the attributes of different 3D shapes.

The part that I assumed would be easy was measuring an edge of each shape. Students had used rulers in the past and we had talked about how to find which side was inches and which was centimeters. We had also talked about always measuring from the end of the ruler (the zero point). I was wrong that this was easy. When I watched several students record inches for centimeters, and one child measure from the 1 inch mark rather than the zero point, I realized that my expectations were not realistic. I had to stop the class for a moment and review measuring from the end of the ruler, and identifying the different sides of the ruler and what each one meant. I then went to the children who were struggling and helped them to see their mistakes and to correct them. I had to ask questions such as, "do you think that you measured in inches here and here if you found that one side was 3 inches and the one across from it was 9 inches. Do you think that makes sense? Should we check to see if those are both correct? I was trying to get students to reason abstractly and quantitatively about what they were doing. (MP2)

As a teacher I need to be ready to adapt to what my students need. I have to be able to read the signs that students are giving me and teach to those signs.

I am constantly being reminded that my lesson plans are just that, plans. Plans are made to be changed. My goal is to meet the needs of my students so that the foundation in math I am setting is strong and my students feel successful with math.

*Did I assume this part was easy?*

*Checks for Understanding: Did I assume this part was easy?*

# Attributes of 3D Shapes Part 2

Lesson 5 of 7

## Objective: SWBAT identify the attributes of 3D shapes and measure the edges in inches and centimeters.

*55 minutes*

#### Warm Up

*15 min*

I begin today by reviewing the terms we use to describe attributes of 3D shapes. I hold up a rectangular prism and ask if anyone can remember what the shape is called? Next I ask if anyone can touch a face on the shape? What about an edge? A corner? A vertex?

I hold up a cylinder, a square pyramid, and a cone and repeat the process.

I then ask if anyone would like to describe a 3D shape for the class to guess? I take a volunteer to come up and describe a shape that they secretly show to me before they begin. I remind them that they will need to give at least 3 clues. After the student gives the clues they ask if anyone can come up and find their shape. We do this 3 times.

Next I ask each table to go up and find the shapes that they built the day before. I help with this process by finding the side of the shape with the name on it, and putting that side face up.

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#### Teaching the Lesson

*30 min*

I post a table on the Smart Board, and give each child a copy for their desk. I tell them that today we will compare the 3 shapes they have. (They built a square pyramid this morning as they arrived at school so they now have a cube, a triangular pyramid and a square pyramid.)

I ask students to pick up the cube and count the number of faces they see and record it on the chart. Next we review the term vertex (corner) and I ask them to count those. We count the number of edges and record that. We repeat this with the other 2 shapes.

I ask students to look for patterns. What do they notice about the shapes, the different numbers of edges, vertices and faces. Do they see any patterns in the numbers of edges, faces or vertices from one shape to another? They should see patterns such as the numbers of vertices and faces are the same for the pyramids. I am asking students to construct viable arguments for what they are noticing (MP 3).

Now I give each student a straight edge. I ask them to measure 1 edge of the cube and write down the number in inches. (It is important to remind students to measure precisely so they can see that all the edges of a cube are the same size (MP6). I ask them to do the same with centimeters. Do they think that all edges will be the same for the cube? I ask them to check.

We repeat this for the square and triangular pyramid. What did they find out?

#### Resources

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#### Closing

*10 min*

Once the students have completed the table we post their count of faces, vertices, edges and lengths on the board. I ask students to look for patterns in the results.

See: Identifying Patterns.

The students share their thoughts about the numbers they see on the board. Most of the patterns had to do with the types of numbers such as even numbers for the triangular prism, finding that the numbers changed by 1 (4 to 5), that there were 2 fours and an eight, etc. I hoped that students would notice that the number of faces and vertices were the same, while the number of edges was greater. I asked some questions to bring out this idea such as which are there more of in a shape, faces or edges? Why might that be? Students were able to identify the answer and give a plausible reason, such as you need an edge to connect every two faces and the faces on the ends so there have to be more edges. (MP3).

After the students point out the differences and patterns, I ask, how many sides does a triangle have (3), how many faces does a triangular prism have (4). How many sides does a square have (4), how many faces does a square prism have (5). If that is true can you guess how many faces a pentagon pyramid might have (6). How do you know that? (the pentagon has 5 sides).

We finish by sharing how a cube and a rectangular prism are similar and different.

#### Resources

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- UNIT 1: What and Where is Math?
- UNIT 2: Adding and Subtracting the Basics
- UNIT 3: Sensible Numbers
- UNIT 4: Sensible Numbers
- UNIT 5: Everything In Its Place
- UNIT 6: Everything in Its Place
- UNIT 7: Place Value
- UNIT 8: Numbers Have Patterns
- UNIT 9: Fractions
- UNIT 10: Money
- UNIT 11: The Numbers Are Getting Bigger
- UNIT 12: More Complex Numbers and Operations
- UNIT 13: Area, Perimeter and More Measurement
- UNIT 14: Length
- UNIT 15: Geometry
- UNIT 16: Getting Ready to Multiply
- UNIT 17: Getting Better at Addition and Subtraction
- UNIT 18: Strategies That Work