Class: Senior Secondary School 1 (SS1, SS 1, SSS1, SSS 1)
Term: 3rd Term
Week: 2
Age: 15 years
Duration: 45 minutes
Subject: Basic Electricity
Curriculum Theme: Basic Electricity
Previous Lesson: Electromagnetism: Faraday’s Laws and Induction.
Topic: ELECTROMAGNETISM
Subject Matter: Lenz’s law of electromagnetic induction, application of electromagnetic induction, experimental verification of induction laws, construction of a simple motor prototype using an electromagnet

Specific Objectives

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

Cognitive Domain:

Define Lenz’s Law of electromagnetic induction.
State at least three applications of electromagnetic induction.
Describe the experimental verification of induction laws.

Affective Domain:

Appreciate the importance of electromagnetic induction in daily life.
Show interest in conducting experiments related to electricity and magnetism.
Cooperate with peers during practical activities.

Psychomotor Domain:

Participate in the experimental verification of induction laws.
Construct a simple motor prototype using an electromagnet.

Work collaboratively in groups to perform experiments.
Share ideas and observations effectively with classmates.

Reference Materials

The following resources were used in planning this lesson:

9 Years Basic Education Curriculum for Basic Science and Technology.
State Unified Scheme of Work for Senior Secondary School 1 (SS1, SS 1, SSS1, SSS 1) Basic Electricity.
New School Physics by P.N. Okeke.

Instructional Materials

The teacher will teach this lesson with the aid of:

Coil wire
Magnets (bar magnet, horseshoe magnet)
Battery
Switch
Paper clips
Galvanometer
Charts illustrating Lenz’s law and electromagnetic induction

Rationale for the Lesson

This lesson helps pupils understand how electricity and magnetism are related and how this relationship is used in many technologies. Learning about electromagnetic induction and constructing a simple motor enables pupils to grasp the principles behind electric generators and motors, which are common in our environment.

Prerequisite/Previous Knowledge

Pupils are expected to have prior knowledge of basic concepts of magnets, magnetic fields, electric current, and simple electromagnets.

Lesson Content/Board Summary

ELECTROMAGNETISM

Lenz’s Law of Electromagnetic Induction

Lenz’s Law states that the direction of an induced electromotive force (e.m.f.) and current is always such that it opposes the change in magnetic flux that produced it.

This law is a consequence of the principle of conservation of energy.

Experimental Verification of Induction Laws

Electromagnetic induction can be experimentally verified using a coil connected to a galvanometer and a bar magnet.

The following observations are made:

When a magnet is moved towards or away from a stationary coil, the galvanometer shows a momentary deflection, indicating an induced current.
The direction of the induced current (and hence the deflection) reverses when the direction of the magnet’s motion is reversed.
No current is induced, and the galvanometer shows no deflection, when the magnet is held stationary inside or near the coil.
The magnitude of the induced current increases with the speed of the magnet’s motion and the strength of the magnetic field.

Applications of Electromagnetic Induction

Electromagnetic induction is a fundamental principle with numerous practical applications. Some common applications include:

Electric generators (both AC and DC)
Transformers for stepping up or stepping down voltage
Induction cooktops
Metal detectors
Credit card readers
Dynamic microphones

Construction of a Simple Motor Prototype using an Electromagnet

A simple DC motor operates on the principle that a current-carrying conductor placed in a magnetic field experiences a force. This force causes rotation.

Basic components of a simple motor prototype include:

A coil of insulated wire (armature)
A source of magnetic field (permanent magnet or electromagnet)
A power source (e.g., battery)
Commutator (often split rings) to reverse current direction
Brushes to connect the coil to the power source

Steps for constructing a simple motor prototype:

Wind insulated copper wire around a cylindrical object to form a coil.
Carefully remove the insulation from the ends of the coil wire.
Create simple supports (e.g., from paper clips) to hold the coil and act as terminals.
Position the coil between the poles of a strong magnet.
Connect the coil ends (via the supports) to a battery to supply current.
Observe the coil rotating due to the magnetic force acting on its sides.

Teaching Methods/Instructional Techniques

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

Instructional Procedures

Step 1: Introduction

Time: 5 minutes
Teaching Skill: Set Induction/Questioning
Teacher’s Activity: The teacher greets the pupils and reviews the previous lesson on electromagnets. The teacher then asks questions such as, “How can we generate electricity using magnets?” and “What happens when a magnet moves near a coil of wire?” This leads into the topic of electromagnetic induction.
Pupils’ Activity: Pupils respond to questions and recall previous knowledge.
Learning Point: Pupils are prepared for the new topic and connect it to prior learning.

Step 2: Introduction to Lenz’s Law

Time: 10 minutes
Teaching Skill: Explanation/Definition
Teacher’s Activity: The teacher introduces Lenz’s Law, defining it clearly and explaining its significance as a statement of energy conservation. The teacher uses diagrams or charts to illustrate the concept of opposing flux.
Pupils’ Activity: Pupils listen attentively, take notes, and ask questions for clarification.
Learning Point: Pupils understand the definition and principle of Lenz’s Law.

Step 3: Experimental Verification of Induction Laws

Time: 10 minutes
Teaching Skill: Demonstration/Observation
Teacher’s Activity: The teacher sets up an experiment using a coil, a galvanometer, and a bar magnet. The teacher demonstrates moving the magnet in and out of the coil, showing the galvanometer deflection and explaining the observations in relation to induced current and its direction. Pupils are guided to note down the observations.
Pupils’ Activity: Pupils observe the experiment, record observations, and discuss what they see.
Learning Point: Pupils visually verify the principles of electromagnetic induction.

Step 4: Applications of Electromagnetic Induction

Time: 5 minutes
Teaching Skill: Explanation/Listing
Teacher’s Activity: The teacher discusses various real-world applications of electromagnetic induction, such as electric generators, transformers, and induction cooktops. The teacher uses charts or examples to explain how these devices work based on the principle.
Pupils’ Activity: Pupils listen, contribute examples if known, and take notes on the applications.
Learning Point: Pupils understand the practical relevance and uses of electromagnetic induction.

Step 5: Construction of a Simple Motor Prototype

Time: 10 minutes
Teaching Skill: Demonstration/Guidance
Teacher’s Activity: The teacher explains the basic principle of a simple DC motor and demonstrates how to construct a prototype using the available materials (coil wire, magnets, battery, paper clips). The teacher guides pupils to participate in assembling their own simple motors.
Pupils’ Activity: Pupils observe the demonstration, follow instructions, and attempt to construct their own simple motor prototypes in groups.
Learning Point: Pupils understand the working principle of a motor and gain practical experience in constructing one.

Step 6: Evaluation/Review

Time: 5 minutes

Teaching Skill: Questioning/Assessment

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

Define Lenz’s Law of electromagnetic induction.
Mention two applications of electromagnetic induction.
Describe briefly how you would experimentally verify electromagnetic induction.
List three components required to construct a simple motor prototype.

Pupils’ Activity: Pupils answer orally and in writing.

Learning Point: Pupils demonstrate understanding of the lesson.

Step 7: Conclusion

Time: 2 minutes
Teaching Skill: Summarization
Teacher’s Activity: The teacher summarizes the key points of the lesson, reiterating the definition of Lenz’s Law, its experimental verification, applications, and the basic principle of a simple motor. The teacher assigns homework for pupils to research more applications of electromagnetic induction.
Pupils’ Activity: Pupils listen to the summary and copy down the homework.
Learning Point: Pupils consolidate their learning and are given tasks for further study.

Lesson Keywords

Electromagnetism – The study of the relationship between electricity and magnetism.
Electromagnetic Induction – The process of generating an electric current in a conductor by changing the magnetic field around it.
Lenz’s Law – States that the direction of an induced current opposes the change in magnetic flux that produced it.
Magnetic Flux – The measure of the number of magnetic field lines passing through a given area.
Galvanometer – An instrument used for detecting and measuring small electric currents.
Motor – A device that converts electrical energy into mechanical energy.

Differentiation

For pupils who grasp concepts quickly, the teacher can encourage them to research and present on more complex applications like eddy current braking. For pupils needing more support, the teacher can provide simplified diagrams and allow more time for hands-on construction, offering one-on-one guidance during the motor prototype activity.

Note for teachers using this lesson plan

Ensure all materials for the experimental verification and motor construction are readily available and in working condition before the lesson. Safety precautions, especially when handling batteries and wires, should be emphasized. Encourage group work to foster collaborative learning and allow pupils to explore and discover principles through practical engagement.