Class: Senior Secondary School 1 (SS1, SS 1, SSS1, SSS 1)
Term: Second Term
Week: 1
Age: 15 years
Duration: 45 minutes
Subject: Basic Electricity
Curriculum Theme: Basic Electricity
Previous Lesson: .
Topic: RESISTANCE
Subject Matter: Definition of resistance, connection of resistors in series, connection of resistors in parallel, connection of resistors in series-parallel, calculation of total resistance for each connection.

Specific Objectives

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

Cognitive Domain:

Define electrical resistance.
State the unit of resistance.
Identify different ways resistors can be connected in a circuit.
Recall the formulas for calculating total resistance in series and parallel connections.

Affective Domain:

Appreciate the importance of resistance in controlling current flow in circuits.
Show interest in analyzing basic electrical circuits.

Psychomotor Domain:

Draw simple circuit diagrams showing series, parallel, and series-parallel resistor connections.
Calculate the total resistance for resistors connected in series, parallel, and series-parallel.

Work collaboratively to solve problems related to resistor connections.

Reference Materials

The following resources were used in planning this lesson:

9 Years Basic Education Curriculum
State Unified Scheme of Work
Basic Electricity for Senior Secondary Schools by P.N. Okeke

Instructional Materials

The teacher will teach this lesson with the aid of:

Resistors
Breadboard
Connecting wires
Power supply
Multimeter
Circuit diagrams

Rationale for the Lesson

This lesson helps pupils understand how resistors control current in electrical circuits. Knowing about resistance and its connections is important for designing and troubleshooting simple electronic devices used in everyday life.

Prerequisite/Previous Knowledge

Pupils have basic knowledge of electric current, voltage, and simple circuits.

Lesson Content/Board Summary

Resistance

Definition of Resistance

Resistance is the opposition to the flow of electric current in a circuit. It converts electrical energy into heat energy.

The unit of resistance is the Ohm (Ω).

Connection of Resistors in Series

Resistors are said to be connected in series when they are joined end-to-end, forming a single path for the current.

The following are characteristics of series connection:

The current is the same through all resistors.
The total voltage across the combination is the sum of the individual voltages across each resistor.
The total resistance (R_T) is the sum of the individual resistances: R_T = R₁ + R₂ + R₃ + …

Connection of Resistors in Parallel

Resistors are connected in parallel when their terminals are connected to the same two points, providing multiple paths for the current.

The following are characteristics of parallel connection:

The voltage across each resistor is the same.
The total current flowing into the combination is the sum of the currents through each resistor.
The reciprocal of the total resistance (1/R_T) is the sum of the reciprocals of the individual resistances: 1/R_T = 1/R₁ + 1/R₂ + 1/R₃ + …

Connection of Resistors in Series-Parallel

A series-parallel connection is a combination of both series and parallel arrangements within a single circuit. To calculate the total resistance, parallel sections are simplified first, then combined with series sections.

The steps to calculate total resistance in a series-parallel circuit are:

Identify and simplify all parallel combinations first to find their equivalent resistances.
Treat these equivalent resistances as series components with the other series resistors.
Calculate the total resistance of the resulting series circuit.

Calculation of Total Resistance

Example formulas:

For two resistors in series: R_T = R₁ + R₂
For two resistors in parallel: R_T = (R₁ * R₂) / (R₁ + R₂)
For multiple resistors in parallel: 1/R_T = 1/R₁ + 1/R₂ + …

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, reviews the previous lesson on basic electrical quantities, and introduces the concept of resistance by asking what opposes the flow of water in a pipe and relating it to electricity.
Pupils’ Activity: Pupils respond to questions and listen attentively.
Learning Point: Pupils are prepared for the new lesson on resistance.

Step 2: Definition and Unit of Resistance

Time: 5 minutes
Teaching Skill: Explanation/Definition
Teacher’s Activity: The teacher defines resistance, explains its role in a circuit, and states its unit (Ohm) and symbol (Ω), writing key points on the board.
Pupils’ Activity: Pupils listen, take notes, and ask questions for clarification.
Learning Point: Pupils understand the definition and unit of resistance.

Step 3: Connection of Resistors in Series

Time: 10 minutes
Teaching Skill: Demonstration/Explanation
Teacher’s Activity: The teacher uses resistors, a breadboard, and connecting wires to demonstrate a series connection. The teacher explains the characteristics of series circuits (same current, additive voltages, additive resistances) and writes the formula for total resistance (R_T = R₁ + R₂ + …) on the board.
Pupils’ Activity: Pupils observe the demonstration, draw the circuit diagram, and copy the formula and characteristics into their notes.
Learning Point: Pupils learn how resistors are connected in series and how to calculate total resistance.

Step 4: Connection of Resistors in Parallel

Time: 10 minutes
Teaching Skill: Demonstration/Explanation
Teacher’s Activity: The teacher demonstrates a parallel connection using the same materials, explaining the characteristics (same voltage, additive currents, reciprocal total resistance) and writing the formula (1/R_T = 1/R₁ + 1/R₂ + …) on the board.
Pupils’ Activity: Pupils observe, draw the circuit diagram, and copy the formula and characteristics.
Learning Point: Pupils learn how resistors are connected in parallel and how to calculate total resistance.

Step 5: Connection of Resistors in Series-Parallel

Time: 5 minutes
Teaching Skill: Explanation/Illustration
Teacher’s Activity: The teacher explains what a series-parallel connection is and how to approach its calculation by simplifying parallel parts first, then combining with series parts. A simple diagram is drawn on the board.
Pupils’ Activity: Pupils listen, observe the diagram, and understand the concept of combined connections.
Learning Point: Pupils understand the concept of series-parallel resistor connections.

Step 6: Calculation of Total Resistance

Time: 5 minutes
Teaching Skill: Problem Solving
Teacher’s Activity: The teacher works through a simple example of calculating total resistance for both series and parallel connections on the board, demonstrating the application of the formulas. For example, R1=2Ω, R2=3Ω in series; R1=2Ω, R2=3Ω in parallel.
Pupils’ Activity: Pupils follow the calculations, ask questions, and solve similar problems in their notebooks.
Learning Point: Pupils practice calculating total resistance for different connections.

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 electrical resistance.
State the unit of resistance.
List two characteristics of resistors connected in series.
If R1 = 5Ω and R2 = 10Ω are connected in parallel, calculate their total resistance.

Pupils’ Activity: Pupils answer orally and in writing.

Learning Point: Pupils demonstrate understanding of the lesson.

Step 8: Conclusion

Time: 5 minutes
Teaching Skill: Summarization/Consolidation
Teacher’s Activity: The teacher summarizes the main points of the lesson, reiterating the definition of resistance and the formulas for series and parallel connections. The teacher assigns homework involving calculations of total resistance for various configurations.
Pupils’ Activity: Pupils listen to the summary, ask any final questions, and copy the homework assignment.
Learning Point: The lesson is consolidated, and pupils are given further practice.

Lesson Keywords

Resistance – The opposition to the flow of electric current.
Resistor – An electrical component that provides resistance in a circuit.
Series Connection – Resistors connected end-to-end, forming a single path for current.
Parallel Connection – Resistors connected across the same two points, providing multiple paths for current.
Ohm (Ω) – The standard unit of electrical resistance.
Total Resistance – The equivalent resistance of a combination of resistors in a circuit.

Differentiation

For visual learners, the teacher will use clear circuit diagrams and live demonstrations. For kinesthetic learners, pupils will be encouraged to handle components and connect simple circuits on a breadboard. Advanced learners can be given more complex series-parallel problems to solve, while struggling learners will receive additional guidance and simpler exercises.

Note for teachers using this lesson plan

Ensure all necessary instructional materials are prepared before the lesson. Emphasize safety precautions when working with electrical components. Encourage pupils to draw and label circuit diagrams accurately, as this helps in understanding the concepts and calculations.