# Surface Area of a Rectangular Prism - What shapes do you see?

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## Objective

Students will be able to distinguish between surface area and volume, and calculate the surface area of a rectangular prism.

#### Big Idea

Can your students wrap a present without wasting paper? After this lesson they will be able to!

## Launch

10 minutes

Opener: As students enter the room, they will immediately begin working on the opener. The opener is a mixture of previously learned questions, and students should work individually, and then as table groups to discuss the methods for solving the questions. During this time I will assist those students who were absent the previous day, and any other students needing help. After approximately 5 minutes, I will call on students to go to the board and solve the opener questions. As with all openers, I will take volunteers to go to the board – the volunteer is expected to explain their reasoning, and other students are expected to follow along with the work and ask questions/make suggestions as necessary. By having a student explain their reasoning while others listen and provide feedback, mathematical practice 3 – construct viable arguments and critique the reasoning of others – becomes a natural part of class. Instructional Strategy - Process for openers

Learning Target: After completion of the opener, I will address the day’s learning targets to the students. In today’s lesson, the intended targets are, “I can distinguish surface area from volume” and “I can calculate the surface area of a rectangular prism.” Students will jot the learning targets down in their agendas (our version of a student planner, there is a place to write the learning target for every day).

## Explore

45 minutes

Brainstorm: Students will brainstorm the concept of surface area using a few guiding questions - what do you think surface area is, what are we finding when we calculate surface area, and how do you think we find the surface area of a rectangular prism?  Students will have two minutes to discuss the questions, and then I will open the floor for discussion, tossing candy at students with good responses.

Surface Area of a Rectangular Prism NotesAfter the discussion, I will go into instruction on finding the surface area of a rectangular prism.  I will ask students to add the information to their foldable as well as their guided notes sheet.  I will walk the students through finding the surface area by identifying the sides and their dimensions of the rectangular prism.  I will ask students to identify congruent sides by using like colors.  It is important to remind students that there are six sides to a rectangular prism, so they need to make sure there are six numbers that they are adding at the end.  Higher students will realize that they can find one side and multiply by 2 (MP 7 and 8), which is a perfectly acceptable way of finding surface area, lower students will most likely stick to finding the area of all 6 sides and adding – which is also okay.  This lesson sets up the learning for the next two lessons on surface area – so it is important for students to get a good conceptual understanding of what they are solving for.  By having students use color, they are actually identifying and making connections between the sides of the figure and the value that they are calculating. This use of modeling makes surface area easier for students to understand (MP 4).

Table Practice: After the example problem, I will work through one more of the class examples, and then ask that students work in their table groups to find the surface area of the rest of the class examples.  During this time I will walk around and provide assistance as necessary, and then I will call on students to go to the board to show the class their work.

Instructional Strategy - How do table challenges work?After the class examples, I will conduct a quick challenge using the quiz applet in smart notebook.  I will use playing cards to randomly choose table groups to respond.  My students love table challenges for a few reasons – they really enjoy competition, and they like the reward of candy or stamps (stamps are a PBIS incentive in my school).

## Summarize + Homework

5 minutes

Write Your Own: To summarize the lesson, I will have students create their own rectangular prism and find the surface area of it.  Students will make a pile of their papers at their tables, and I will walk around and collect them.  This activity is fun for students because they think it is cool that they can make up their own problem – they are always baffled that I can stand at the board and make up problems, so it makes them feel really smart when they get to do it!  Additionally, the activity gives me feedback of who gets it and who doesn’t, and what steps I need to take next.

HomeworkAfterwards, students will begin to work on their homework assignment. Philosophy on Homework