Work, Energy and Power Basic Science JSS 2 Second Term Lesson Notes Week 1

Subject: Basic Science
Class: JSS 2
Term: Second Term
Week: Week 1
Topic: Work, Energy, and Power
Sub-topic: Understanding the Concepts and Applications
Duration: 45 minutes
Entry Behaviour: Students should have a basic understanding of physical concepts such as force and motion.
Key Words: Work, Energy, Power, Force, Motion, Joule, Watt
Behavioural Objectives: By the end of the lesson, students should be able to define work, energy, and power, explain the relationship between them, and apply these concepts to solve problems.
Embedded Core Skills: Critical thinking, Problem-solving, Communication
Learning Materials: Lagos State Scheme of Work, Physical and Health Education Book 2
Reference Books: Lagos State Scheme of Work, Physical and Health Education Book 2

Content:

Introduction:

• Briefly revise the previous topic, which was about Force and Motion.

Concepts of Work, Energy, and Power:

• Define work as the product of force and distance moved in the direction of the force.
• Explain energy as the capacity to do work, and power as the rate at which work is done.
• Discuss the relationship between work, energy, and power, and their units of measurement.

Introduction

Work and energy are essential concepts in our daily lives. Energy is needed for any work to be done. When we relate work and energy, they share the same measurement unit called Joule.

Concepts of Work, Energy, and Power

Work

Work occurs when a body moves in the direction of a force, expressed as:

Work = force x distance moved in the direction of the force

W = f x d

Where: W = work done, f = force, d = distance moved in the direction of the force.

If the force applied cannot cause motion or displacement, no work is done.

Energy

Energy is the capacity to do work. It can be stored (potential energy) or in motion (kinetic energy). The relationship between work and energy is expressed by the formulas:

Potential energy (PE) = mgh

Kinetic Energy (KE) = ½mv^2

Power

Power is the rate at which work is done, defined as:

Power = Work done / Time

P = W/t

The SI unit of power is Joules per second (J/s) or Watts (W).

Calculation Involving Work Done Per Time (Power)

Example: How much power does a student of 25kg mass climbing a stair with 20 steps, where each step is 15cm high, in 30s have? (Assuming g = 10m/s^2)

Energy Transfer: Conversion of Potential Energy to Kinetic Energy

In phenomena like a simple pendulum, potential energy converts to kinetic energy and vice versa at different points of motion.

PRESENTATION

The lesson is presented in stages:

Step 1: Revision of previous topics

Step 2: Introduction of the new topic

Step 3: Encourage learners’ contributions through questions, suggestions, and corrections.

1. Energy is the capacity to do _______. a) eat b) sleep c) work d) play
2. Work is said to be done when a body moves in the direction of the _______. a) cloud b) force c) tree d) river
3. The SI unit of power is _______. a) kilogram b) watt c) meter d) liter
4. Power is defined as the rate of doing _______. a) rest b) play c) work d) eat
5. Potential energy is the energy possessed by a body due to its _______. a) mass b) color c) position d) speed
6. Kinetic energy is the energy possessed by a body in _______. a) rest b) motion c) sleep d) silence
7. The formula for calculating work done is force multiplied by _______. a) distance b) time c) speed d) weight
8. Work done is measured in _______. a) Joules b) Watts c) Newtons d) Meters
9. Power is calculated by dividing work done by _______. a) distance b) force c) time d) mass
10. Energy transfer involves the conversion of _______ energy to kinetic energy. a) electrical b) potential c) chemical d) thermal
11. In a simple pendulum, potential energy is maximum at point _______. a) A b) B c) C d) D
12. The unit of power is _______ per second. a) Joules b) Newtons c) Watts d) Kilograms
13. A stone on the ground has _______ energy. a) kinetic b) potential c) electrical d) chemical
14. Work done and energy transferred are measured in _______. a) liters b) volts c) joules d) grams
15. The concept of work, energy, and power is important in understanding _______ phenomena. a) natural b) artificial c) mechanical d) mystical

CLASS ACTIVITIES

Teacher guides students in activities on boiling and evaporation, discussing their findings. Students deduce factors affecting evaporation based on observations.

1. What is the definition of energy?
   • Energy is the capacity to do work.
2. How is work defined in the context of physics?
   • Work is defined as the product of force and the distance moved in the direction of the force.
3. What is the relationship between work and energy?
   • Work and energy are closely related; work is done when energy is transferred from one object to another or converted from one form to another.
4. Can you explain the concept of potential energy?
   • Potential energy is the energy possessed by an object due to its position or configuration. It is stored energy that can be converted into kinetic energy.
5. What factors determine the amount of kinetic energy an object possesses?
   • The amount of kinetic energy an object possesses is determined by its mass and velocity.
6. How is power defined, and what is its significance?
   • Power is defined as the rate at which work is done or energy is transferred. It measures how quickly work is done and is significant in understanding the efficiency of processes and machines.
7. What are the units used to measure work, energy, and power?
   • Work and energy are measured in joules (J), while power is measured in watts (W) or joules per second (J/s).
8. Can you provide examples of energy transfer in everyday life?
   • Examples of energy transfer include electrical energy being converted into light energy in a bulb, chemical energy in food being converted into kinetic energy during physical activity, and potential energy in water stored in a dam being converted into electrical energy in a hydroelectric power plant.
9. How does a simple pendulum illustrate the conversion of potential energy to kinetic energy?
   • In a simple pendulum, potential energy is maximum at the highest point of swing, where kinetic energy is zero. As the pendulum swings down, potential energy decreases while kinetic energy increases, illustrating the conversion between the two forms of energy.
10. Why is the understanding of work, energy, and power important in various scientific disciplines and practical applications?
    • Understanding work, energy, and power is crucial in physics and engineering for analyzing mechanical systems, designing efficient machines, and solving real-world problems related to energy production, consumption, and conversion

Presentation: Step 1: The teacher revises the previous topic, which was Force and Motion.
Step 2: The teacher introduces the new topic, Work, Energy, and Power, explaining their definitions and importance.
Step 3: Teacher’s Activities:

• Define work, energy, and power using simple examples.
• Provide illustrations and real-life scenarios to demonstrate the concepts.
• Show students how to calculate work, energy, and power using relevant formulas.

Learners Activities:

• Listen attentively to the teacher’s explanations.
• Engage in class discussions and ask questions for clarification.
• Participate in solving example problems and calculations.

Assessment:

• Evaluate students’ understanding through class discussions, questions, and problem-solving activities.

Ten Evaluation Questions:

1. What is work?
2. Define energy.
3. Explain power.
4. How are work and energy related?
5. What are the units used to measure power?
6. Can you give an example of potential energy?
7. Calculate the work done when a force of 10N moves an object 5 meters.
8. What is the formula for calculating power?
9. Describe the concept of kinetic energy.
10. Why is understanding work, energy, and power important in science?

Conclusion: In today’s lesson, we have explored the fundamental concepts of work, energy, and power. We have learned how these concepts are interconnected and their significance in understanding various physical phenomena. By applying these principles, we can solve problems related to force, motion, and energy transfer effectively.

EVALUATION

1. What is energy?
2. What is power?
3. What is kinetic energy?
4. What is potential energy?
5. Calculate the power of a student climbing stairs.