Class: Senior Secondary School 1 (SS1, SS 1, SSS1, SSS 1)
Term: 1st Term
Week: 10
Age: 15 years
Duration: 45 minutes
Subject: Basic Electronics
Curriculum Theme: Basic Electronics
Previous Lesson: Ohm’s Law: Definition and Expression.
Topic: RELATIONSHIP BETWEEN VOLTAGE, CURRENT, AND RESISTANCE: Simple Experiment to Determine Ohm’s Law
Subject Matter: Setting up a simple Ohm’s Law experiment, taking voltage and current readings, plotting V against I graph, determining resistance from slope, interpreting experimental results

Specific Objectives

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

Cognitive Domain:

Define Ohm’s Law.
Explain the relationship between voltage, current, and resistance.
Interpret experimental results from an Ohm’s Law experiment.

Affective Domain:

Appreciate the importance of precision and safety in electrical experiments.
Demonstrate patience and attention to detail while taking readings.

Psychomotor Domain:

Set up a simple circuit to demonstrate Ohm’s Law.
Take accurate voltage and current readings.
Plot a V-I graph from experimental data.
Determine resistance from the slope of the V-I graph.

Collaborate effectively with peers during the experiment.

Reference Materials

The following resources were used in planning this lesson:

9 Years Basic Education Curriculum
State Unified Scheme of Work
Basic Electronics for Senior Secondary Schools 1 by Any Relevant Publisher

Instructional Materials

The teacher will teach this lesson with the aid of:

Resistors
Variable resistor (rheostat)
Connecting wires
Dry cells (power source)
Ammeter
Voltmeter
Graph sheet
Calculator

Rationale for the Lesson

This lesson helps pupils understand the fundamental relationship between voltage, current, and resistance in an electrical circuit. Understanding Ohm’s Law is important for analyzing and designing basic electronic circuits, making it applicable to many technological fields.

Prerequisite/Previous Knowledge

Pupils should have a basic understanding of electrical current, voltage, and resistance, and be familiar with simple circuit components and their symbols.

Lesson Content/Board Summary

RELATIONSHIP BETWEEN VOLTAGE, CURRENT, AND RESISTANCE: Ohm’s Law

Definition of Ohm’s Law

Ohm’s Law states that the current flowing through a metallic conductor is directly proportional to the potential difference (voltage) across its ends, provided that the temperature and other physical conditions remain constant.

Ohm’s Law Formula

The mathematical representation of Ohm’s Law is:

V = I x R

Where:

V = Voltage (Potential Difference) in Volts (V)
I = Current in Amperes (A)
R = Resistance in Ohms (Ω)

Experimental Setup for Ohm’s Law

To verify Ohm’s Law, a simple circuit is set up using the following components:

Power source (dry cells)
Resistor (the conductor whose resistance is to be determined)
Ammeter (connected in series to measure current)
Voltmeter (connected in parallel across the resistor to measure voltage)
Variable resistor (rheostat) to vary the current and voltage
Connecting wires

Procedure for Ohm’s Law Experiment

The steps to conduct a simple Ohm’s Law experiment are:

Connect the components as shown in the circuit diagram, ensuring the ammeter is in series and the voltmeter in parallel across the resistor.
Ensure all connections are tight.
Adjust the variable resistor to obtain different current readings.
For each current reading (I), record the corresponding voltage reading (V).
Take several pairs of (V, I) readings.

Plotting the V-I Graph and Determining Resistance

After taking readings, a graph is plotted:

Plot voltage (V) on the y-axis and current (I) on the x-axis.
The graph should be a straight line passing through the origin for an ohmic conductor.
The resistance (R) of the conductor is determined from the slope of this V-I graph.
Slope = Change in V / Change in I = R.

Interpretation of Results

A straight-line graph passing through the origin confirms Ohm’s Law, indicating that the resistance of the conductor is constant over the range of voltages and currents applied.

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 reviews the previous lesson on basic electrical concepts like voltage, current, and resistance. The teacher then introduces the topic by asking pupils if they know how these three quantities are related in a circuit.
Pupils’ Activity: Pupils respond to questions and listen attentively to the introduction of the new topic.
Learning Point: Pupils recall previous knowledge and are prepared for the new lesson.

Step 2: Explanation of Ohm’s Law

Time: 10 minutes
Teaching Skill: Explanation/Lecture
Teacher’s Activity: The teacher defines Ohm’s Law, states its formula (V=IR), and explains each component (V, I, R) and their units. The teacher also explains the conditions under which Ohm’s Law holds true.
Pupils’ Activity: Pupils listen, take notes, and ask questions for clarification.
Learning Point: Pupils understand the definition and formula of Ohm’s Law.

Step 3: Demonstration of Experimental Setup

Time: 10 minutes
Teaching Skill: Demonstration/Explanation
Teacher’s Activity: The teacher displays the instructional materials and demonstrates how to set up the circuit for verifying Ohm’s Law. The teacher explains the function of each component and how meters are connected (ammeter in series, voltmeter in parallel).
Pupils’ Activity: Pupils observe the setup carefully, identify the components, and ask questions about the connections.
Learning Point: Pupils learn how to correctly set up an electrical circuit for Ohm’s Law.

Step 4: Conducting the Experiment and Taking Readings

Time: 10 minutes
Teaching Skill: Practical Application/Guidance
Teacher’s Activity: The teacher guides the pupils (or a group of pupils) to adjust the variable resistor and take various corresponding voltage and current readings from the ammeter and voltmeter. The teacher emphasizes precision and accuracy.
Pupils’ Activity: Pupils actively participate in taking readings, recording them in a table, and ensuring accuracy.
Learning Point: Pupils gain practical experience in taking electrical measurements.

Step 5: Plotting the V-I Graph and Determining Resistance

Time: 5 minutes
Teaching Skill: Instruction/Guidance
Teacher’s Activity: The teacher instructs pupils on how to plot the collected data on a graph sheet, with voltage on the y-axis and current on the x-axis. The teacher then explains how to calculate the resistance from the slope of the resulting straight line.
Pupils’ Activity: Pupils begin plotting the graph and calculate the slope as guided by the teacher.
Learning Point: Pupils learn to represent experimental data graphically and derive resistance from it.

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 Ohm’s Law.
State the formula for Ohm’s Law and identify its components.
List three components required to set up an experiment to verify Ohm’s Law.
Explain how resistance is determined from a V-I graph.

Pupils’ Activity: Pupils answer orally and in writing.

Learning Point: Pupils demonstrate understanding of the lesson.

Step 7: Conclusion

Time: 5 minutes
Teaching Skill: Summarization/Consolidation
Teacher’s Activity: The teacher summarizes the key points of the lesson, reiterating the relationship between voltage, current, and resistance as described by Ohm’s Law and its experimental verification. The teacher assigns homework, which may include completing the V-I graph and calculation of resistance.
Pupils’ Activity: Pupils listen to the summary and copy down the homework.
Learning Point: Pupils consolidate their understanding of the lesson.

Lesson Keywords

Voltage – The electrical potential difference between two points in a circuit, measured in volts (V).
Current – The flow of electric charge, measured in amperes (A).
Resistance – The opposition to the flow of electric current, measured in ohms (Ω).
Ohm’s Law – A fundamental law stating that current is directly proportional to voltage and inversely proportional to resistance.
Ammeter – An instrument used to measure electric current.
Voltmeter – An instrument used to measure potential difference (voltage).
Resistor – A passive two-terminal electrical component that implements electrical resistance as a circuit element.
Graph – A diagram showing the relationship between two or more variables, often used to visualize experimental data.

Differentiation

For visual learners, the demonstration of the circuit setup and the V-I graph will be highly beneficial. Kinesthetic learners will benefit from actively participating in setting up the circuit and taking readings. Struggling learners can be paired with more advanced pupils for support during the experiment and graph plotting. Advanced learners can be challenged to consider factors that might cause deviations from Ohm’s Law or to design variations of the experiment.

Note for teachers using this lesson plan

Ensure all electrical connections are secure and that pupils understand safety precautions when working with electrical circuits. Supervise pupils closely during the practical activity. Provide pre-drawn V-I graph axes if time is limited, or allow pupils to draw their own to practice graphing skills. Emphasize the importance of accurate readings for meaningful results.