Class: Senior Secondary School 1 (SS1, SS 1, SSS1, SSS 1)
Term: First Term
Week: 5
Age: 15 years
Duration: 45 minutes
Subject: Physics
Curriculum Theme: Physics
Previous Lesson: Rectilinear Acceleration.
Topic: Motion
Subject Matter: Causes and effects of motion, types of force as contact force and force field, friction as solid friction, static friction and dynamic friction, coefficient of limiting friction, advantages of friction, disadvantages of friction, methods of reducing friction

Specific Objectives

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

Cognitive Domain:

Define force and friction.
Distinguish between contact force and force field, giving examples.
Identify the different types of solid friction.
State at least three advantages and three disadvantages of friction.
List at least two methods of reducing friction.

Affective Domain:

Appreciate the role of forces and friction in everyday life.
Show interest in understanding how friction affects motion.

Psychomotor Domain:

Observe demonstrations of contact and field forces.
Illustrate situations where friction is beneficial or problematic.

Participate actively in class discussions on forces and friction.
Collaborate with peers to identify examples of forces.

Reference Materials

The following resources were used in planning this lesson:

9 Years Basic Education Curriculum
State Unified Scheme of Work
New School Physics for Senior Secondary Schools by M.W. Anyakoha
Comprehensive Certificate Physics by P.N. Okeke

Instructional Materials

The teacher will teach this lesson with the aid of:

Spring balance
Magnets
Rough and smooth surfaces
Blocks
Charts illustrating types of friction and forces
Measuring scale

Rationale for the Lesson

This lesson helps pupils understand the fundamental concepts of force and friction, which explain why objects move or stop. It enables them to identify how friction impacts daily activities and the functioning of machines, and how to manage its effects.

Prerequisite/Previous Knowledge

Pupils have been taught about basic concepts of motion and force in Junior Secondary School.

Lesson Content/Board Summary

Causes and Effects of Motion, Types of Force, and Friction

Causes and Effects of Motion

Motion is caused by a force acting on an object. A force can make a stationary object move, change the speed or direction of a moving object, or stop a moving object.

Types of Force

A force is a push or a pull that tends to change the state of rest or uniform motion of an object.

Forces can be broadly classified into two main types:

Contact Force: This is a force that acts on an object only when there is physical contact between the interacting objects.

Examples of contact forces include:

Friction
Tension
Air resistance
Normal force
Applied force

Force Field (Non-Contact Force): This is a force that acts on an object even when there is no physical contact between the interacting objects.

Examples of force fields include:

Gravitational force
Magnetic force
Electrostatic force

Friction

Friction is a resistive force that opposes the relative motion or tendency of motion between two surfaces in contact.

Types of Solid Friction

Solid friction can be classified into:

Static Friction: This is the friction that opposes the start of motion between two surfaces in contact when they are at rest relative to each other. It acts when an object is stationary but a force is applied to make it move.
Dynamic Friction (Kinetic Friction): This is the friction that opposes the relative motion between two surfaces that are already in motion.

Dynamic friction can be further divided into:

Sliding Friction: Occurs when one object slides over another.
Rolling Friction: Occurs when one object rolls over another.

Coefficient of Limiting Friction

The coefficient of limiting friction (μs) is the ratio of the limiting frictional force (F) to the normal reaction (R) when an object is just about to move.

μs = F/R

Advantages of Friction

The following are advantages of friction:

It enables walking and running without slipping.
It allows vehicles to move and stop (braking).
It holds objects in place (e.g., nails in wood).
It enables writing with a pen or pencil.
It allows machines to grip and transmit power (e.g., belts).

Disadvantages of Friction

The following are disadvantages of friction:

It causes wear and tear of machine parts.
It produces unwanted heat in machines.
It reduces the efficiency of machines by wasting energy.
It makes it difficult to move heavy objects.

Methods of Reducing Friction

The following are methods of reducing friction:

Lubrication: Applying oil, grease, or graphite between surfaces.
Using Ball Bearings or Roller Bearings: Replacing sliding friction with rolling friction.
Streamlining: Designing objects with smooth, aerodynamic shapes to reduce air/fluid resistance.
Polishing Surfaces: Making surfaces smoother to reduce irregularities.
Using Wheels: Allowing objects to roll instead of slide.

Teaching Methods/Instructional Techniques

Discussion, Lecture, Demonstration, Question and Answer, Visual Aids

Instructional Procedures

Step 1: Introduction

Time: 5 minutes
Teaching Skill: Set Induction
Teacher’s Activity: The teacher greets the pupils and asks them to recall what they know about motion and forces from their previous classes. The teacher then introduces the topic “Motion” and specifically, the causes and effects of motion, types of forces, and friction.
Pupils’ Activity: Pupils respond to the teacher’s questions and listen attentively to the introduction.
Learning Point: Pupils are reminded of prior knowledge and introduced to the new lesson.

Step 2: Presentation of Subject Matter – Causes and Effects of Motion

Time: 5 minutes
Teaching Skill: Explanation/Illustration
Teacher’s Activity: The teacher explains that force is the cause of motion and describes how a force can start, stop, or change the motion of an object. The teacher gives simple examples like pushing a trolley or kicking a ball.
Pupils’ Activity: Pupils listen and provide their own examples of forces causing motion.
Learning Point: Pupils understand force as the cause of motion and its effects.

Step 3: Presentation of Subject Matter – Types of Force

Time: 10 minutes
Teaching Skill: Demonstration/Differentiation
Teacher’s Activity: The teacher defines force and then distinguishes between contact forces and force fields. The teacher demonstrates contact force using a spring balance to pull a block and a force field using magnets attracting or repelling without touching. Examples for each type of force are provided.
Pupils’ Activity: Pupils observe the demonstrations, identify contact and field forces from examples, and take notes.
Learning Point: Pupils can differentiate between contact and force field forces with examples.

Step 4: Presentation of Subject Matter – Friction and its Types

Time: 7 minutes
Teaching Skill: Explanation/Classification
Teacher’s Activity: The teacher defines friction as a resistive force. Using rough and smooth surfaces with a block, the teacher introduces and explains static friction and dynamic friction (sliding and rolling friction). The teacher also introduces the concept of coefficient of limiting friction.
Pupils’ Activity: Pupils observe the demonstration, describe the different types of friction, and ask questions for clarification.
Learning Point: Pupils understand the definition of friction and its types.

Step 5: Presentation of Subject Matter – Advantages and Disadvantages of Friction

Time: 5 minutes
Teaching Skill: Discussion/Analysis
Teacher’s Activity: The teacher leads a discussion on the benefits (e.g., walking, braking) and problems (e.g., wear and tear, heat generation) associated with friction, guiding pupils to list these points.
Pupils’ Activity: Pupils list advantages and disadvantages of friction, contributing their own ideas.
Learning Point: Pupils identify the practical advantages and disadvantages of friction.

Step 6: Presentation of Subject Matter – Methods of Reducing Friction

Time: 5 minutes
Teaching Skill: Problem-solving/Application
Teacher’s Activity: The teacher guides pupils to suggest and explain various methods of reducing friction, such as lubrication, using ball bearings, streamlining, and polishing surfaces. The teacher uses examples like oiling bicycle chains.
Pupils’ Activity: Pupils suggest and explain methods to reduce friction.
Learning Point: Pupils learn practical ways to reduce friction.

Step 7: Evaluation/Review

Time: 5 minutes

Teaching Skill: Questioning/Assessment

Teacher’s Activity: The teacher evaluates the learning by asking the following questions:

Define force and friction.
Differentiate between contact force and force field, giving two examples for each.
List three advantages and three disadvantages of friction.
State two methods by which friction can be reduced.

Pupils’ Activity: Pupils answer orally and in writing.

Learning Point: Pupils demonstrate understanding of the lesson.

Step 8: Conclusion

Time: 3 minutes
Teaching Skill: Summarization/Homework Assignment
Teacher’s Activity: The teacher summarizes the key points of the lesson, reinforcing the understanding of forces and friction. The teacher then assigns homework: “Explain how friction is important in the movement of vehicles.”
Pupils’ Activity: Pupils listen to the summary and copy the homework assignment.
Learning Point: Pupils consolidate their learning and apply knowledge to a practical situation.

Lesson Keywords

Force – A push or a pull that tends to change the state of rest or uniform motion of an object.
Contact Force – A force that acts between objects that are physically touching.
Force Field – A force that acts on an object without physical contact.
Friction – A resistive force that opposes relative motion between surfaces in contact.
Static Friction – Friction that opposes the start of motion between surfaces at rest.
Dynamic Friction – Friction that opposes relative motion between surfaces that are already moving.
Coefficient of Limiting Friction – The ratio of the limiting frictional force to the normal reaction when an object is just about to move.

Differentiation

For pupils who grasp concepts quickly, the teacher will encourage them to research and present on specific applications of friction in engineering. For pupils needing more support, the teacher will provide simplified diagrams and allow for more one-on-one explanations and practical examples.

Note for teachers using this lesson plan

Ensure all demonstrations are conducted safely and clearly. Encourage pupils to relate the concepts of force and friction to their daily experiences to enhance understanding. Emphasize the practical implications of friction in various contexts.