# Modeling 3D Figures

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## Objective

Students will be able to use what they know about 3D figures to create models of figures.

#### Big Idea

This lesson is awesome because it allows students to apply what they have learned and create some 3D figures and cut them apart to see the cross section. Students will also have an opportunity to review vocabulary in this lesson.

## Lesson Beginning

5 minutes

Class should begin by pointing out that this is a day for review, giving students a chance to apply what they know to make figures and to practice the vocabulary included in that figure creation. Have students respond to the following prompt then share and compare responses. Have students decide which nets will satisfy the prompt and why.

Prompt: Draw a net that would form a square pyramid. I want to see that students can create the net. I am looking for a distinct difference between a square pyramid and a square prism, which is a common mistake. The response to the prompt will give me information on the students’ understanding and application of vocabulary.

## Lesson Middle

30 minutes

The Stages Chart will allow students the opportunity to create the figures that have been discussed in class. Students will mold a 2D shape then make a 3D figure using the 2D shape as the base.  Additionally, using modeling clay, students will be able to take the figures apart and analyze the components of each figure and see the results of cross sections. In pairs or groups of three, students will use modeling clay to create each of the two-dimensional figures on the chart then move to the other stages on the chart. As students work to build the models of each stage, discussion between group members will be about how they know what the shape or polygon will look like.  At each stage, they need to draw a sketch of what they see. Each member of the group needs to have a copy of the chart to complete to use for study purposes. As the groups work on the chart, I will walk around to see how students progress through the chart. Are they able to identify the base in the 3D figure? Are they able to use the 2D figure as a base? Do they understand perpendicular and parallel? Are they using those distinctions when they cut? When the time is up, students will share their work, either through the sketches they created or by holding up their models to generate class discussion. Did groups create different models? If all groups created the same models, can they create a different one? Does it meet all of the requirements in the chart? Would any of the sketches in the chart change with the new model?

After discussion, I will distribute the I Have cards to students and have them practice the vocabulary by completing the game. One student in the group reads a card aloud. The last sentence on the card is actually a question that identifies another shape or polygon. The student who has the shape or polygon described on the previous card then stands and reads their card. The objective of the game is to use vocabulary to identify shapes and polygons. Students have to listen attentively to know when there turn has come to read. The cards are connected and each card has to be read to complete the game. Students can be divided into smaller groups of 10 to play, or into pairs to use cards. After the first round, decide if students might benefit from shuffling the cards and playing a second round with different cards. This review will serve as a formative assessment to determine students’ knowledge.

## Lesson End

5 minutes

Have students respond to a prompt for an Exit Ticket: Describe the difference between the cross sections of a triangular prism and a rectangular prism. Explain how you determine the differences. The exit ticket will give a picture of what students understand about cross sections and if they can visualize the cross sections for different figures.