# Nets

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## Objective

SWBAT create a formula for finding the surface area and volume of 3D figures

#### Big Idea

What is the difference between surface area and volume?

## Launch

5 minutes
• POD

As students enter the room, they will have a seat, take out their Problem of the Day (POD) sheet and begin to work on the question on the SMARTboard. The POD allows students to use MP 3 continually based on the discussions we have about the problem each day.

The POD today will ask students to discuss their understanding of the difference between surface area and volume and include examples. I want students to be able to determine which measurement is necessary to solve particular problems and to be sure about which measurement, surface area or volume, is applicable. It is important that they know the difference.

## Explore

30 minutes

To explore the concept of surface area, students will receive a copy of the “Nets” sheets. We will discuss the general meaning of surface area and volume. I want students to understand that surface area is the number of square units needed to cover the outside of a figure while volume is the number of cubic units that can be put inside a three dimensional figure. We can refer to the foldables they created in class as a resource. Students will cut out the nets and use the dotted line to fold each net into a 3D figure. Then they will measure the dimensions of the faces and calculate the surface area and volume. I have found that students conceptually understand surface area if we look at each face as a polygon. Students seem to have a better understanding of finding the area of four rectangular faces and two rectangular bases and adding them together than by memorizing the formula for a rectangular prism. After students have found the surface area and volume of each figure, we will work to develop a formula that students can use to find the surface area and volume of each type of solid. They can use centimeter cubes if that is helpful for them.

## Landing

5 minutes

Exit ticket: Describe an example when it is necessary to know the surface area of a figure. Why wouldn’t you use the volume in this example?

I want to make sure that students genuinely understand the difference between the two measurements. If the exit tickets indicate they don’t, we can continue to develop understanding of the difference as we moved through the unit.