Class: Senior Secondary School 1 (SS1, SS 1, SSS1, SSS 1)
Term: First Term
Week: 10
Age: 15 years
Duration: 45 minutes
Subject: Physics
Curriculum Theme: Mechanics (Work, Energy and Power)
Previous Lesson: Vectors.
Topic: WORK, ENERGY AND POWER
Subject Matter: Concept of work, concept of energy, concept of power, relationship between work and energy, interchangeability of work and energy in physical processes, common examples of work and power in daily activities

Specific Objectives

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

Cognitive Domain:

Define work, energy, and power.
State the units of work, energy, and power.
Explain the relationship between work and energy.
Identify common examples of work and power in daily activities.

Affective Domain:

Appreciate the importance of work, energy, and power in understanding physical processes.
Demonstrate interest in solving problems related to work and power.

Psychomotor Domain:

Calculate basic power when given work done and time taken.
Illustrate situations where work is done or energy is transferred.

Actively participate in group discussions on real-life applications of work, energy, and power.

Reference Materials

The following resources were used in planning this lesson:

9 Years Basic Education Curriculum (Physics for Senior Secondary Schools)
State Unified Scheme of Work for Senior Secondary School Physics
New School Physics by P.N. Okeke and Anyakoha
https://www.physicsclassroom.com/class/energy
https://www.khanacademy.org/science/physics/work-and-energy

Instructional Materials

The teacher will teach this lesson with the aid of:

Charts/posters illustrating work, energy, and power scenarios.
Simple load objects (e.g., a book, a small block).
Measuring tape.
Stopwatch.
Chalkboard/Whiteboard.

Rationale for the Lesson

This lesson helps pupils understand the fundamental concepts of work, energy, and power, which are essential for explaining motion and changes in physical systems. Understanding these concepts allows pupils to better comprehend how things move, how machines operate, and how energy is used in everyday life.

Prerequisite/Previous Knowledge

Pupils are expected to have prior knowledge of force, motion, distance, and time from their previous lessons.

Lesson Content/Board Summary

WORK, ENERGY AND POWER

Concept of Work

Work is done when a force causes an object to move through a distance in the direction of the force. If the force and displacement are in the same direction, work is positive. If they are perpendicular, no work is done by that force.

The formula for work is: Work (W) = Force (F) × Distance (d) × cos(θ), where θ is the angle between the force and the displacement.

The SI unit of work is the Joule (J).

The following are conditions for work to be done:

A force must be applied to an object.
The object must move through a distance.
The motion must be in the direction of the applied force or have a component in that direction.

Concept of Energy

Energy is the capacity or ability to do work.

The SI unit of energy is the Joule (J).

The following are common forms of mechanical energy:

Kinetic Energy (KE): Energy possessed by an object due to its motion. Formula: KE = ½mv² (where m = mass, v = velocity).
Potential Energy (PE): Energy possessed by an object due to its position or state.
Gravitational Potential Energy (GPE): Energy due to an object’s height above a reference point. Formula: GPE = mgh (where m = mass, g = acceleration due to gravity, h = height).
Elastic Potential Energy: Energy stored in elastic materials (e.g., stretched spring).

Concept of Power

Power is the rate at which work is done or energy is transferred.

The formula for power is: Power (P) = Work (W) / Time (t) or Power (P) = Force (F) × Velocity (v).

The SI unit of power is the Watt (W), which is equivalent to 1 Joule per second (J/s).

Relationship Between Work and Energy

The Work-Energy Theorem states that the net work done on an object is equal to the change in its kinetic energy.

Work done = Change in Kinetic Energy (W = ΔKE = ½mv² – ½mu²).

Work and energy are interchangeable. When work is done on an object, energy is transferred to it. When an object does work, it loses energy.

Common Examples of Work and Power in Daily Activities

The following are examples of work and power:

Work:
- Pushing a trolley across the floor.
- Lifting a bag of cement onto a truck.
- Kicking a football.
Power:
- A car engine pulling a car up a hill quickly (high power).
- A person climbing stairs quickly versus slowly.
- An electric fan rotating (rate of doing work against air resistance).

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 understand by ‘force’ and ‘motion’. The teacher then introduces the topic by asking pupils if they consider lifting a heavy box work, and if a person who lifts it faster does more work.
Pupils’ Activity: Pupils respond to the questions and engage in the introductory discussion.
Learning Point: Pupils recall prior knowledge and are introduced to the concept of work, energy, and power.

Step 2: Concept of Work

Time: 10 minutes
Teaching Skill: Explanation/Demonstration
Teacher’s Activity: The teacher defines work, explains its formula (W=Fdcosθ) and SI unit (Joule). The teacher demonstrates using a simple load object to show work being done when moving it across a distance. The teacher also explains the conditions for work to be done using examples.
Pupils’ Activity: Pupils listen, take notes, and observe the demonstration. They answer questions about conditions for work.
Learning Point: Pupils understand the definition, formula, unit, and conditions for work.

Step 3: Concept of Energy

Time: 10 minutes
Teaching Skill: Explanation/Illustration
Teacher’s Activity: The teacher defines energy as the ability to do work and states its SI unit (Joule). The teacher then explains different forms of mechanical energy, focusing on kinetic energy and potential energy (gravitational), giving their respective formulae and examples.
Pupils’ Activity: Pupils listen, ask questions for clarification, and note down the definitions and formulae.
Learning Point: Pupils understand the definition, forms, and units of energy.

Step 4: Concept of Power

Time: 7 minutes
Teaching Skill: Explanation/Problem Solving
Teacher’s Activity: The teacher defines power as the rate of doing work and provides its formula (P=W/t) and SI unit (Watt). The teacher works through a simple calculation example on the board: “If 100 J of work is done in 5 seconds, what is the power?”
Pupils’ Activity: Pupils listen, copy the definition and formula, and attempt to solve the calculation example.
Learning Point: Pupils understand the definition, formula, unit of power, and can perform basic calculations.

Step 5: Relationship Between Work and Energy

Time: 5 minutes
Teaching Skill: Linking Concepts
Teacher’s Activity: The teacher explains the Work-Energy Theorem, stating that work done on an object changes its kinetic energy. The teacher also explains the interchangeability of work and energy with simple examples like a falling object gaining kinetic energy as potential energy decreases.
Pupils’ Activity: Pupils listen and contribute examples of energy conversion they know.
Learning Point: Pupils understand that work done is a transfer of energy and the concept of the Work-Energy Theorem.

Step 6: Common Examples of Work and Power

Time: 3 minutes
Teaching Skill: Application/Discussion
Teacher’s Activity: The teacher uses charts/posters to show various daily activities and guides pupils to identify situations where work is done and where power is demonstrated. For instance, lifting a heavy object (work) versus lifting it quickly (power).
Pupils’ Activity: Pupils identify and discuss examples from the charts and their own experiences.
Learning Point: Pupils can apply the concepts of work and power to real-life situations.

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 work and state its SI unit.
What is energy? Mention two forms of mechanical energy.
Explain power and write its formula.
If a force of 50 N moves an object by 10 m in 2 seconds, calculate the work done and the power.

Pupils’ Activity: Pupils answer orally and in writing.

Learning Point: Pupils demonstrate understanding of the lesson.

Step 8: Conclusion

Time: 2 minutes
Teaching Skill: Summarization
Teacher’s Activity: The teacher summarizes the key points of the lesson, reiterating the definitions of work, energy, and power, their units, and their relationship. The teacher assigns homework for pupils to list five more examples of work and power from their homes.
Pupils’ Activity: Pupils listen to the summary and copy down the homework.
Learning Point: Pupils consolidate their understanding of the topic.

Lesson Keywords

Work – The product of force and displacement in the direction of the force.
Energy – The capacity to do work.
Power – The rate at which work is done or energy is transferred.
Joule – The SI unit of work and energy.
Watt – The SI unit of power.
Kinetic Energy – Energy of motion.
Potential Energy – Stored energy due to position or state.

Differentiation

For pupils who grasp concepts quickly, the teacher can provide more complex problems involving angles for work done or problems requiring conversion of units. For pupils needing extra support, the teacher can provide simpler, direct questions and visual aids, allowing them to define terms or identify basic examples.

Note for teachers using this lesson plan

Ensure that the demonstrations are clear and visible to all pupils. Encourage pupils to relate the concepts to everyday activities to make the learning more meaningful. Pay attention to the correct application of units in calculations. Emphasize the vector nature of force and displacement when discussing work.