PRIMARY 6: BASIC SCIENCE – THIRD TERM | WEEK 2

TOPIC: SIMPLE MACHINES – LEVERS

A: TEACHING AND LEARNING MATERIALS

1. Bottle opener.
2. Scissors.
3. Wheelbarrow.
4. Seesaw illustration.
5. Pliers.
6. Lever chart.
7. Ruler and small objects for demonstration.

B: REFERENCE MATERIALS

1. Scheme of work.
2. Recommended Basic Science textbook for Primary 6.
3. Online educational resources.

C: PREVIOUS KNOWLEDGE

The pupils have learnt that simple machines help people perform work more easily and have seen tools such as scissors, bottle openers and wheelbarrows.

D: PERFORMANCE OBJECTIVES

By the end of the lesson, pupils should be able to:

1. Define a machine.
2. Define a simple machine.
3. Explain a lever.
4. Identify the parts of a lever.
5. Mention the three classes of levers.
6. Give examples of each class of lever.
7. State uses of levers.
8. Explain how levers make work easier.

E: CONTENT

Meaning of a Machine

A machine is a device that helps us to perform work more easily. A simple machine is a basic device that changes the size or direction of a force to make work easier. Examples include:

• Lever
• Pulley
• Inclined plane
• Wheel and axle
• Screw
• Wedge

Meaning of a Lever

A lever is a rigid bar that turns around a fixed point called the fulcrum.

Parts of a Lever

A lever has three important parts:

1. Fulcrum – the fixed turning point.
2. Load – the object to be moved.
3. Effort – the force applied to move the load.

First-Class Lever

In a first-class lever, the fulcrum is between the effort and the load. Examples:

• Seesaw.
• Scissors.
• Pliers.

Effort – Fulcrum – Load

Second-Class Lever

In a second-class lever, the load is between the fulcrum and the effort. Examples:

• Wheelbarrow.
• Bottle opener.
• Nutcracker.

Fulcrum – Load – Effort

Third-Class Lever

In a third-class lever, the effort is between the fulcrum and the load. Examples:

• Broom.
• Fishing rod.
• Human forearm when lifting an object.

Fulcrum – Effort – Load

Uses of Levers

Levers are used for:

1. Lifting loads.
2. Cutting materials.
3. Opening bottle tops.
4. Moving heavy objects.
5. Gripping objects.

F: LESSON PRESENTATION

F1: Teachers’ Activities

1. Introduces simple machines.
2. Defines a lever.
3. Demonstrates the parts of a lever.
4. Explains the three classes of levers.
5. Shows examples of each class.
6. Guides pupils to identify effort, load and fulcrum.
7. Demonstrates how a lever makes work easier.

F2: Pupils’ Activities

1. Define a simple machine.
2. Identify levers.
3. Name the parts of a lever.
4. Classify different levers.
5. Identify effort, load and fulcrum.
6. Mention uses of levers.

G: CONCLUSION

The teacher revises the meaning, parts and three classes of levers. Pupils are encouraged to identify examples of levers used at home and in school.

H: EVALUATION GUIDE

Pupils should be able to answer the following questions:

1. What is a simple machine?
2. What is a lever?
3. Name the three parts of a lever.
4. What is a fulcrum?
5. Give two examples of first-class levers.
6. Give two examples of second-class levers.
7. Give two examples of third-class levers.
8. State three uses of levers.