Lesson Plan
Wrap It Up!
Students will define surface area and calculate the surface area of rectangular prisms using nets.
Understanding surface area helps us solve real-world problems like how much wrapping paper is needed for a gift or how much paint to buy for a room. It builds essential spatial reasoning skills!
Audience
6th Grade Students
Time
30 minutes
Approach
Interactive slides, guided practice, and a hands-on activity with nets.
Materials
Whiteboard or Projector, Markers or Pens, Surface Area Slide Deck, Surface Area Warm-Up, Surface Area Worksheet, Surface Area Answer Key, Scissors, Tape or Glue, and Pre-printed nets of rectangular prisms (one per student)
Prep
Teacher Preparation
15 minutes
- Review the Surface Area Slide Deck and practice the script.
* Print and cut out pre-made nets of rectangular prisms (e.g., from a template or a blank cereal box unfolded). Ensure there is one net per student.
* Print copies of the Surface Area Warm-Up and Surface Area Worksheet.
* Have scissors and tape/glue readily available.
* Review the Surface Area Answer Key.
Step 1
Warm-Up: Flat or Fab?
5 minutes
- Distribute the Surface Area Warm-Up.
* Ask students to consider the prompt: "Imagine you have a flat piece of cardboard. What 3D shape could you make from it? Draw how it would look flattened out."
* Briefly discuss their ideas, leading into the concept of nets.
Step 2
Introduction: What is Surface Area?
7 minutes
- Use the Surface Area Slide Deck to introduce surface area.
* Slide 1: Title Slide.
* Slide 2: "What's the Buzz?" Discuss what surface area means in simple terms (the total area of all the faces of a 3D object). Use the analogy of wrapping a gift.
* Slide 3: "Unfolding the Mystery: Nets!" Explain what a net is (a 2D representation of a 3D shape that can be folded to form the shape). Show an example of a rectangular prism net.
* Slide 4: "Counting the Squares." Demonstrate how to find the area of each face on a net and then add them up to find the total surface area. Work through a simple rectangular prism example together.
Step 3
Hands-On Activity: Net Challenge!
10 minutes
- Distribute the pre-printed nets, scissors, and tape/glue.
* Instruct students to carefully cut out their nets and then fold and tape/glue them into a 3D rectangular prism.
* Once assembled, have students work with a partner to identify each face and calculate the area of each face on their physical prism. They should then add these areas to find the total surface area of their prism. Encourage them to draw or label the dimensions on their nets before folding.
* Circulate to provide support and answer questions.
Step 4
Guided Practice & Worksheet
6 minutes
- Distribute the Surface Area Worksheet.
* Review the first problem on the worksheet as a class, guiding students through identifying the faces and calculating their areas.
* Allow students to work independently or in pairs on the remaining problems.
* Circulate to provide support and check for understanding. Explain that they can complete any unfinished problems for homework.
Step 5
Cool Down: Quick Check
2 minutes
- Ask students to write down one thing they learned about surface area today and one question they still have.
* Collect these as an exit ticket.
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Slide Deck
Wrap It Up!
Exploring Surface Area
How much 'outside' does a 3D shape have?
Welcome students and introduce the lesson's exciting topic. Ask them to think about how much wrapping paper they'd need for a gift.
What's the Buzz?
What is Surface Area?
- The total area of all the faces (sides) of a 3D object.
- Imagine you're wrapping a gift! The amount of wrapping paper you need is the surface area.
- It's like finding the area of every flat part and adding them all together!
Define surface area simply. Use the gift-wrapping analogy to make it relatable. Ask students for other examples where knowing the 'outside' area would be useful (e.g., painting a box, covering a book).
Unfolding the Mystery: Nets!
What is a Net?
- A net is a 2D (flat) shape that can be folded to form a 3D object.
- It shows all the faces of the 3D shape laid out flat.
(Imagine a diagram of a rectangular prism net here)
Introduce the concept of a net. Show a visual representation. Emphasize that it's the 3D shape flattened out. Ask students if they've ever seen boxes unfolded like this.
Counting the Squares
How to Calculate Surface Area using a Net
- Identify all the faces of the 3D shape.
- Calculate the area of each individual face.
- Remember: Area of a rectangle = length × width
- Add up the areas of all the faces to get the total surface area.
Example: Let's say we have a rectangular prism with sides 3cm, 4cm, and 5cm.
- Face 1 (Front): 3cm x 5cm = 15 cm²
- Face 2 (Back): 3cm x 5cm = 15 cm²
- Face 3 (Top): 4cm x 5cm = 20 cm²
- Face 4 (Bottom): 4cm x 5cm = 20 cm²
- Face 5 (Side): 3cm x 4cm = 12 cm²
- Face 6 (Other Side): 3cm x 4cm = 12 cm²
Total Surface Area = 15 + 15 + 20 + 20 + 12 + 12 = 94 cm²
Guide students through an example. Focus on identifying each face, calculating its area (length x width), and then summing all the areas. Use a simple rectangular prism.
Warm Up
Surface Area Warm-Up: Flat or Fab?
Instructions: Take a few minutes to think about the question below and write down your ideas. We'll discuss them as a class!
Imagine you have a flat piece of cardboard, like a box that has been completely unfolded. What 3D shape could you make from it? Draw how it would look flattened out (its "net"). You can draw any 3D shape you can think of!
Bonus Question: Why do you think it might be useful to flatten out a 3D shape like this in real life?
Worksheet
Surface Area Practice
Instructions: For each problem, calculate the surface area of the given rectangular prism. Show your work!
Problem 1:
A rectangular prism has a length of 6 cm, a width of 3 cm, and a height of 2 cm.
-
Draw a simple net for this prism:
-
Calculate the area of each face:
- Top:
- Bottom:
- Front:
- Back:
- Side 1:
- Side 2:
- Top:
-
Total Surface Area:
Problem 2:
A shoebox is 10 inches long, 6 inches wide, and 4 inches tall. What is its surface area?
Problem 3:
Mr. Garcia wants to paint a storage box that is 1.5 meters long, 1 meter wide, and 0.5 meters high. How much surface area will he need to paint?
Answer Key
Surface Area Answer Key
Problem 1:
A rectangular prism has a length of 6 cm, a width of 3 cm, and a height of 2 cm.
-
Draw a simple net for this prism: (Student drawing will vary but should show 6 rectangular faces that can form the prism)
Example Net Structure:+---+ | T | +---+---+---+ | S | F | S | +---+---+---+ | B | +---+*T=Top, B=Bottom, F=Front, S=Side
-
Calculate the area of each face:
- Top: 6 cm x 3 cm = 18 cm²
- Bottom: 6 cm x 3 cm = 18 cm²
- Front: 6 cm x 2 cm = 12 cm²
- Back: 6 cm x 2 cm = 12 cm²
- Side 1: 3 cm x 2 cm = 6 cm²
- Side 2: 3 cm x 2 cm = 6 cm²
-
Total Surface Area:
18 cm² + 18 cm² + 12 cm² + 12 cm² + 6 cm² + 6 cm² = 72 cm²
Problem 2:
A shoebox is 10 inches long, 6 inches wide, and 4 inches tall. What is its surface area?
- Front/Back faces: 2 * (10 in * 4 in) = 2 * 40 in² = 80 in²
- Top/Bottom faces: 2 * (10 in * 6 in) = 2 * 60 in² = 120 in²
- Side faces: 2 * (6 in * 4 in) = 2 * 24 in² = 48 in²
- Total Surface Area: 80 in² + 120 in² + 48 in² = 248 in²
Problem 3:
Mr. Garcia wants to paint a storage box that is 1.5 meters long, 1 meter wide, and 0.5 meters high. How much surface area will he need to paint?
- Front/Back faces: 2 * (1.5 m * 0.5 m) = 2 * 0.75 m² = 1.5 m²
- Top/Bottom faces: 2 * (1.5 m * 1 m) = 2 * 1.5 m² = 3 m²
- Side faces: 2 * (1 m * 0.5 m) = 2 * 0.5 m² = 1 m²
- Total Surface Area: 1.5 m² + 3 m² + 1 m² = 5.5 m²