Class: Senior Secondary School 1 (SS1, SS 1, SSS1, SSS 1)
Term: 2nd Term
Week: 4
Age: 15 years
Duration: 45 minutes
Subject: Physics
Curriculum Theme: Physics
Previous Lesson: Transfer of Heat Energy.
Topic: ELECTRIC CHARGES
Subject Matter: Production of electric charges by different methods, types of charges as positive and negative, distribution of charges on conductors, storage of charges, application of charge concepts in lightning conductor

Specific Objectives

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

Cognitive Domain:

Define electric charge.
Identify and differentiate between positive and negative electric charges.
Describe methods of producing electric charges.
Explain how electric charges are distributed on conductors.
State how electric charges can be stored.
Explain the working principle of a lightning conductor.

Affective Domain:

Show interest in understanding the concept of electric charges.
Appreciate the importance of lightning conductors in ensuring safety.

Psychomotor Domain:

Produce electric charges using simple materials like a comb and cloth.
Draw a simple diagram illustrating charge distribution on a conductor.

Work cooperatively during practical demonstrations.

Reference Materials

The following resources were used in planning this lesson:

9 Years Basic Education Curriculum for Physics (Senior Secondary Education)
State Unified Scheme of Work for Physics SSS 1
New School Physics by P.N. Okeke and Anyakoha
https://www.physicsclassroom.com/class/estatics/Lesson-2/Charging-Methods
https://www.britannica.com/science/lightning-rod

Instructional Materials

The teacher will teach this lesson with the aid of:

Plastic ruler or comb
Woolen or silk cloth
Pieces of paper
Electroscope (if available)
Metal objects (e.g., spoon, key)
Charts illustrating lightning conductors and charge distribution
Safety notes on handling static electricity

Rationale for the Lesson

Understanding electric charges helps pupils to grasp fundamental principles of electricity, which are present in many daily experiences. This lesson also explains how devices like lightning conductors protect buildings, making pupils aware of practical applications of physics for safety.

Prerequisite/Previous Knowledge

Pupils have basic knowledge of atoms and their components (protons, neutrons, electrons) from previous science lessons.

Lesson Content/Board Summary

ELECTRIC CHARGES

Definition of Electric Charge

Electric charge is a fundamental property of matter that causes it to experience a force when placed in an electromagnetic field. It is carried by subatomic particles like electrons and protons.

Types of Electric Charges

There are two types of electric charges:

Positive Charge: This is the charge carried by protons. An object becomes positively charged when it loses electrons.
Negative Charge: This is the charge carried by electrons. An object becomes negatively charged when it gains electrons.

Like charges repel each other, while unlike charges attract each other.

Methods of Producing Electric Charges

Electric charges can be produced by the following methods:

Friction: Rubbing two different materials together can transfer electrons from one material to another, making both materials electrically charged. For example, rubbing a plastic comb with a dry cloth.
Conduction (Contact): When a charged object touches an uncharged conductor, some of the charge is transferred to the uncharged conductor.
Induction: This is the process of charging an object without direct contact. A charged object brought near an uncharged conductor can cause a redistribution of charges in the conductor, leading to temporary or permanent charging if earthed.

Distribution of Charges on Conductors

When an electric charge is placed on an isolated conductor:

The charges quickly distribute themselves over the outer surface of the conductor.
The charge density (charge per unit area) is highest at sharp points or regions of smaller radius of curvature on the conductor.
Inside a hollow conductor, there is no electric field and thus no net charge.

Storage of Charges

Electric charges can be stored using devices known as capacitors. A common example of an early charge storage device is the Leyden jar.

Application of Charge Concepts: Lightning Conductor

A lightning conductor (or lightning rod) is a metal rod mounted on top of a building and connected to the ground through a thick copper wire.

Its working principle is based on the distribution of charges at sharp points:

The sharp points of the lightning conductor ionize the air around them.
During a thunderstorm, the highly charged cloud induces an opposite charge on the sharp points of the conductor.
This opposite charge leaks into the atmosphere, neutralizing the charge in the cloud and preventing a lightning strike.
If lightning does strike, the conductor provides a low-resistance path for the huge electric current to flow safely into the earth, protecting the building from damage.

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 questions about common observations related to static electricity, e.g., “Have you ever felt a small shock after walking on a carpet and touching a doorknob?” or “What happens when you rub a plastic comb through your hair and hold it near small pieces of paper?”
Pupils’ Activity: Pupils respond to the questions and share their experiences.
Learning Point: Pupils are introduced to the concept of electric charges through familiar phenomena.

Step 2: Production of Electric Charges

Time: 10 minutes
Teaching Skill: Demonstration/Explanation
Teacher’s Activity: The teacher defines electric charge and demonstrates how charges can be produced by friction (rubbing a plastic ruler with wool/cloth and attracting paper bits). The teacher also explains conduction and induction as other methods.
Pupils’ Activity: Pupils observe the demonstration, ask questions, and take notes. Some pupils may be invited to try the friction experiment.
Learning Point: Pupils learn how electric charges are defined and produced by different methods.

Step 3: Types of Electric Charges

Time: 5 minutes
Teaching Skill: Explanation
Teacher’s Activity: The teacher explains the two types of electric charges (positive and negative) and states the rule of attraction and repulsion between charges.
Pupils’ Activity: Pupils listen, take notes, and ask clarifying questions.
Learning Point: Pupils understand the two types of charges and their interactions.

Step 4: Distribution of Charges on Conductors

Time: 7 minutes
Teaching Skill: Explanation/Illustration
Teacher’s Activity: The teacher explains how charges distribute on the surface of conductors, emphasizing the higher density at sharp points. The teacher may draw a simple diagram on the board or use a chart.
Pupils’ Activity: Pupils listen, observe the diagrams, and copy notes.
Learning Point: Pupils learn about the distribution of charges on conductors, especially at sharp points.

Step 5: Storage of Charges

Time: 3 minutes
Teaching Skill: Lecture
Teacher’s Activity: The teacher briefly introduces the concept of storing charges, mentioning capacitors and the Leyden jar.
Pupils’ Activity: Pupils listen and note down the key terms.
Learning Point: Pupils are aware that electric charges can be stored.

Step 6: Application: Lightning Conductor

Time: 10 minutes
Teaching Skill: Explanation/Discussion
Teacher’s Activity: The teacher uses a chart or diagram to explain the structure and working principle of a lightning conductor, linking it to the concept of charge distribution at sharp points and safety.
Pupils’ Activity: Pupils observe the diagram, ask questions about its function, and contribute to the discussion on its importance.
Learning Point: Pupils understand the practical application of electric charge concepts in lightning conductors.

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 electric charge.
List two methods of producing electric charges.
State the two types of electric charges and how they interact.
Explain how electric charges are distributed on a conductor.
Briefly explain the working principle of a lightning conductor.

Pupils’ Activity: Pupils answer orally and in writing.

Learning Point: Pupils demonstrate understanding of the lesson.

Step 8: Conclusion

Time: 2 minutes
Teaching Skill: Consolidation
Teacher’s Activity: The teacher summarizes the key points of the lesson, reiterating the definition, types, production, distribution, storage, and application of electric charges. The teacher then assigns homework.
Pupils’ Activity: Pupils listen to the summary and copy the homework.
Learning Point: Pupils review the main concepts of the lesson.

Lesson Keywords

Electric Charge – A fundamental property of matter that causes it to experience a force in an electromagnetic field.
Positive Charge – The type of charge associated with protons, typically resulting from electron loss.
Negative Charge – The type of charge associated with electrons, typically resulting from electron gain.
Friction – A method of producing electric charges by rubbing two materials together.
Conduction – Charging an object by direct contact with a charged object.
Induction – Charging an object without direct contact by bringing a charged object nearby.
Conductor – A material that allows electric charges to move freely through it.
Lightning Conductor – A device that protects buildings from lightning strikes by providing a path for current to the ground.

Differentiation

For pupils who grasp concepts quickly, the teacher may encourage them to research more complex applications of static electricity. For pupils who need more support, the teacher will provide simplified explanations and more direct guidance during practical demonstrations.

Note for teachers using this lesson plan

Ensure all safety precautions are taken during demonstrations involving static electricity. Emphasize real-life examples to make the lesson more relatable. Encourage active participation and questions from pupils.