Lesson Plan – Lesson 6 Surface Area Objectives and Habits of Mind

• To identify edges, faces and vertices (Level 3/ 4) • To find the surface area of a cube (Level 5) • To find the surface area of a cuboid (Level 6) • To find the surface area of 3D shapes from nets. (Level 7) • To work well in a group, listening attentively and taking on different roles when needed.

• To negotiate and follow ground rules, to ensure fairness and cooperation when working with others.

Keywords

Face, Surface Area, Vertex, Edge,

Mental and Oral Starter

Pupils to say how many faces, vertices and edges each 3D shape has.

Main Activity

Each member of the group should select a 3D shape to work on and cut it out. Pupils to write down the number of faces, edges and vertices the shape has. Pupils then calculate the surface area of their chosen shape.

They then glue the shape onto the group’s A3 paper and write down how they worked it out, checking that the rest of the group agree with their method. Pupils can use the nets provided to work out the surface area of some of the shapes. Support - provide 3D models for the pupils.

Plenary

Pupils to reflect on the success criteria.

LO To find the surface area of 3D shapes

Key Words: Face, Edge, Vertex, Surface Area

RAG

30-Apr-20

Starter Activity How many vertices, edges and faces?

Can you name any of these solids?

Level Shape Space Measure 3/4

I can identify edges, faces and vertices

5

I can find the surface area of a cube

6

I can find the surface area of a cuboid.

7 /8

I can calculate volumes and surface area of cylinders.

I am starting the lesson on level _____________________ By the end of this lesson I want to be able to _____________________

Starter Activity How many vertices, edges and faces?

Starter Activity How many vertices, edges and faces?

Surface area of a cube

How can we find the surface area of a cube of length 4cm?

4

All six faces of a cube have the same area.

The area of each face is

4

×

4

=

16

Therefore, Surface area of a cube = 16

x 6 = 96cm 2

Surface area of a cuboid

To find the

surface area

of a cuboid, we calculate the total area of all of the faces.

A cuboid has 6 faces.

The top and the bottom of the cuboid have the same area.

The sides of the cuboid have the same area.

The front and the back of the cuboid have the same area.

6 8 4

Surface area of a cuboid = 2 ×

(8 × 4)

Top and bottom + 2 × (

6 × 8)

Front and back + 2 ×

(6 × 4)

Left and right side Surface area of a cuboid = (2

× 32)

+ (2

× 48)

+ (2

× 24)

Working out surface are from nets.

Here is the net of a triangular based pyramid (tetrahedron.) What is its surface area?

5.2 cm Area of each face = ½

bh

= ½ × 6 × 5.2

= 15.6 cm 2 Surface area = 4 × 15.6

=

62.4 cm 2

6 cm

Here is the net of a triangular prism.

What is its surface area?

13 cm 10 cm

60

12 cm

260 200 260

20 cm

60

We can work out the area of each face and write it in the diagram of the net.

Then add each area together to get the total surface area = 60 + 60 + 200 + 260 + 260 = 840 cm 2

5

Here is the net of a Surface area of a cylinder

3

To find the surface area find the area of the rectangle and the area of the circles and add them together.

The rectangles wraps around the circles so the length of the rectangle is the same as the circumference of the circles.

Today’s Task In your groups Each member of the group should select a 3D shape to work on and cut it out.

Write down the number of faces, edges and vertices the shape has.

Find the surface area of the shape.

Glue the shape onto the group’s A3 paper and write down how you worked it out. The rest of your group must agree with your method.

3 12m Cylinder 2m Cubes 4cm 3cm 4cm Cuboids 6cm Cuboid 5m 2m 7m Triangular Prism 5cm 4cm 6cm 10cm Square Based Pyramid 5m 3m 4.5m

30m 30m

4m 3m 6m 12m 2m 30cm 30cm 5cm 4cm 10cm 6cm

Find the surface area of a ...........

Work out the area of each face.

Your working out will go in here.

Your answer in cm 2