Simple Electrical Calculation in Basic Electricity for JSS 1

Class: Junior Secondary School 1 (JSS 1 / JS1)
Term: 3rd Term
Week: 9
Age: 12 years
Duration: 45 minutes
Subject: Basic Science and Technology
Curriculum Theme: Basic Technology
Previous Lesson: Measuring Instruments in Basic Electricity.
Topic: BASIC ELECTRICITY III
Subject Matter: Simple electrical calculation

Specific Objectives

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

Step 7: Evaluation/Review

Time: 5 minutes
Teaching Skill: Questioning/Assessment
Teacher’s Activity: The teacher evaluates the learning by asking the following questions:

1. Define voltage and state its unit.
2. State Ohm’s Law.
3. Write down the formula for calculating current, given voltage and resistance.
4. A bulb has a resistance of 5 Ω and a current of 2 A flows through it. Calculate the voltage across the bulb.

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
Teacher’s Activity: The teacher summarizes the key points of the lesson, emphasizing the importance of Ohm’s Law in simple electrical calculations. The teacher then gives homework, asking pupils to solve two similar problems.
Pupils’ Activity: Pupils listen to the summary and copy down the homework.
Learning Point: Pupils consolidate their learning and apply it independently.

Home Task: Record two correct examples of BASIC ELECTRICITY III from the lesson or home environment and explain each in your own words.

Lesson Keywords

• Voltage – The electrical pressure that pushes current.
• Current – The flow of electric charge.
• Resistance – The opposition to the flow of current.
• Ohm’s Law – The relationship between voltage, current, and resistance.
• Circuit – A complete path for electricity to flow.

Differentiation

For struggling learners, the teacher will provide additional simpler examples and one-on-one guidance. Advanced learners will be given more complex problems or asked to explain the real-life applications of Ohm’s Law.

Note for teachers using this lesson plan

Ensure pupils understand the basic definitions of voltage, current, and resistance before introducing Ohm’s Law. Emphasize the units for each quantity. Encourage pupils to show all their working steps when solving problems. Visual aids like the formula triangle can be very helpful for JSS 1 pupils.

Cognitive Domain:

• Define voltage, current, and resistance.
• State Ohm’s Law and its formula.
• Identify the standard units for voltage, current, and resistance.

Affective Domain:

• Appreciate the importance of understanding basic electrical calculations.
• Show interest in solving simple electrical problems.

Psychomotor Domain:

• Apply Ohm’s Law to calculate unknown values (voltage, current, or resistance) in simple circuits.
• Solve at least two simple electrical calculation problems correctly.

Social Domain:

• Participate actively in class discussions about electrical calculations.
• Share their understanding of the formulas with peers.

Reference Materials

The following resources were used in planning this lesson:

• 9 Years Basic Education Curriculum.
• State Unified Scheme of Work.
• MacMillan Basic Science and Technology for Junior Secondary Schools 1.
• https://www.waeconline.org.ng/e-learning
• https://www.youtube.com/c/OmoOyeEducation

Instructional Materials

The teacher will teach this lesson with the aid of:

• Chart showing Ohm’s Law formula triangle.
• Diagrams of simple electrical circuits.
• Whiteboard and markers.
• Calculators (optional, for demonstration).

Rationale for the Lesson

This lesson enables pupils to understand how voltage, current, and resistance are related in an electrical circuit. It helps them to perform basic calculations, which is important for understanding how electrical appliances work safely and efficiently in their daily lives.

Prerequisite/Previous Knowledge

Pupils have prior knowledge of basic electrical components such as cells, bulbs, switches, and wires, and have been introduced to the concepts of voltage, current, and resistance in previous lessons.

Lesson Content/Board Summary

Simple Electrical Calculations

Key Electrical Quantities and Units

In an electrical circuit, three main quantities are related:

• Voltage (V): This is the electrical pressure that pushes current through a circuit. Its unit is Volts (V).
• Current (I): This is the flow of electric charge. Its unit is Amperes (A).
• Resistance (R): This is the opposition to the flow of current. Its unit is Ohms (Ω).

Ohm’s Law

Ohm’s Law states that the current flowing through a conductor between two points is directly proportional to the voltage across the two points, and inversely proportional to the resistance between them. This applies when the temperature and other physical conditions remain constant.

The formula for Ohm’s Law is:

V = I × R

Where:

• V = Voltage (in Volts, V)
• I = Current (in Amperes, A)
• R = Resistance (in Ohms, Ω)

From this formula, we can also find:

• Current: I = V / R
• Resistance: R = V / I

Worked Examples

Example 1: Calculating Current

A simple circuit has a voltage of 12 V and a resistance of 4 Ω. Calculate the current flowing through the circuit.

Step 1: Identify the given values.

• Voltage (V) = 12 V
• Resistance (R) = 4 Ω

Step 2: State the formula for current.

• I = V / R

Step 3: Substitute the values into the formula and calculate.

• I = 12 V / 4 Ω
• I = 3 A

Therefore, the current flowing through the circuit is 3 Amperes.

Example 2: Calculating Voltage

If a current of 2 A flows through a resistor with a resistance of 6 Ω, what is the voltage across the resistor?

Step 1: Identify the given values.

• Current (I) = 2 A
• Resistance (R) = 6 Ω

Step 2: State the formula for voltage.

• V = I × R

Step 3: Substitute the values into the formula and calculate.

• V = 2 A × 6 Ω
• V = 12 V

Therefore, the voltage across the resistor is 12 Volts.

Example 3: Calculating Resistance

A circuit has a voltage of 9 V and a current of 3 A flowing through it. What is the resistance of the circuit?

Step 1: Identify the given values.

• Voltage (V) = 9 V
• Current (I) = 3 A

Step 2: State the formula for resistance.

• R = V / I

Step 3: Substitute the values into the formula and calculate.

• R = 9 V / 3 A
• R = 3 Ω

Therefore, the resistance of the circuit is 3 Ohms.

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 them to recall what they learned about voltage, current, and resistance in the previous lesson. The teacher then introduces the topic of simple electrical calculations.
Pupils’ Activity: Pupils respond to the questions and listen attentively to the introduction.
Learning Point: Pupils recall previous knowledge and are prepared for the new topic.

Step 2: Explanation of Key Terms and Units

Time: 7 minutes
Teaching Skill: Explanation
Teacher’s Activity: The teacher briefly reviews the definitions of voltage, current, and resistance, and their respective units (Volts, Amperes, Ohms), writing them on the board.
Pupils’ Activity: Pupils listen, take notes, and ask questions for clarification.
Learning Point: Pupils refresh their understanding of key electrical terms and units.

Step 3: Introduction of Ohm’s Law and Formula

Time: 8 minutes
Teaching Skill: Lecture/Explanation
Teacher’s Activity: The teacher introduces Ohm’s Law, explaining its relationship between voltage, current, and resistance. The teacher writes the main formula (V = I × R) and its derivations (I = V/R, R = V/I) on the board.
Pupils’ Activity: Pupils copy the law and formulas into their notebooks and pay attention to the explanation.
Learning Point: Pupils learn Ohm’s Law and its mathematical expressions.

Step 4: Demonstrating Formula Application with a Chart

Time: 5 minutes
Teaching Skill: Demonstration
Teacher’s Activity: The teacher uses a chart or draws a “formula triangle” on the board to visually demonstrate how to derive I, V, or R when two values are known, making it easier for pupils to remember.
Pupils’ Activity: Pupils observe the demonstration and try to recall the formula derivations.
Learning Point: Pupils understand how to easily recall the different forms of Ohm’s Law.

Step 5: Solving Worked Example 1 (Calculating Current)

Time: 6 minutes
Teaching Skill: Problem Solving/Demonstration
Teacher’s Activity: The teacher presents the first worked example (calculating current) from the board summary, guiding pupils step-by-step through the solution process on the board.
Pupils’ Activity: Pupils follow along, copy the example, and ask questions if they are confused.
Learning Point: Pupils learn how to apply Ohm’s Law to calculate current.

Step 6: Solving Worked Example 2 & 3 (Calculating Voltage and Resistance)

Time: 9 minutes
Teaching Skill: Guided Practice
Teacher’s Activity: The teacher presents the second and third worked examples (calculating voltage and resistance). The teacher encourages pupils to attempt the steps before revealing the full solution, providing guidance as needed.
Pupils’ Activity: Pupils attempt to solve the problems, then compare their answers with the teacher’s solution, correcting any mistakes.
Learning Point: Pupils practice applying Ohm’s Law to calculate voltage and resistance.