Model Transmission Systems and Communication Technology for SS 3

Class: SS 3
Term: First Term
Week: 11
Age: 16-17 years
Duration: 45 minutes
Subject: Physics
Curriculum Theme: Physics in Technology
Previous Lesson: Physics in the Real World and Technology Applications
Topic: PHYSICS IN THE REAL WORLD (PHYSICS IN TECHNOLOGY)
Subject Matter: Construction of a model transmission system using a transformer

Specific Objectives

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

Cognitive Domain

• Identify the key components of a model electrical transmission system.
• Explain the function of a transformer in power transmission.
• Describe the basic principle of power transmission using step-up and step-down transformers.

Psychomotor Domain

• Construct a simple model electrical transmission system using a transformer.
• Demonstrate the operation of the constructed model transmission system.

Affective Domain

• Appreciate the application of physics principles in modern technology.
• Work collaboratively in groups to assemble the model.

Reference Materials

The following resources were used in planning this lesson:

• 2025 Revised 9 Years Basic Education Curriculum
• Relevant State Unified Scheme of Work
• New School Physics for Senior Secondary Schools
• The HeadTeacher Scheme of work

Instructional Materials

The teacher will teach this lesson with the aid of:

• A small step-up transformer
• A small step-down transformer
• Connecting wires
• A low-voltage DC power supply (e.g., 6V battery or power pack)
• Two small light bulbs (e.g., 3V or 6V LED bulbs)
• Two bulb holders
• A switch
• Diagrams illustrating a power transmission system

Rationale for the Lesson

This lesson provides a practical understanding of how electrical power is efficiently transmitted over long distances. By constructing a model, students can visualize the role of transformers in stepping up and stepping down voltage, which is a fundamental concept in modern electrical engineering and technology. This hands-on experience reinforces theoretical knowledge and highlights the real-world applications of physics.

Prerequisite/Previous Knowledge

Students should have a basic understanding of electric circuits, current, voltage, and the working principles of a transformer (step-up and step-down).

Lesson Content/Board Summary

PHYSICS IN THE REAL WORLD (PHYSICS IN TECHNOLOGY)

Construction of a Model Transmission System Using a Transformer

An electrical transmission system is a network used to transport electricity from power generation plants to substations, and then to consumers. Transformers play a crucial role in making this transmission efficient.

Role of Transformers in Power Transmission

1. Step-up Transformer: At the power station, a step-up transformer increases the voltage of the generated electricity to a very high level (e.g., from 11kV to 330kV). This high voltage reduces the current for a given power, thereby minimizing energy loss (I²R loss) during transmission over long distances.
2. Step-down Transformer: Near consumption areas, step-down transformers reduce the high transmission voltage to lower, safer levels suitable for distribution to homes and industries (e.g., from 330kV to 33kV, then to 415V/240V).

Components for a Model Transmission System

To construct a simple model transmission system, the following components are typically needed:

1. Power Source: Provides the initial low voltage (e.g., a battery).
2. Step-up Transformer: Increases the voltage from the source.
3. Transmission Line: Long connecting wires representing the power lines.
4. Step-down Transformer: Reduces the voltage for the load.
5. Load: A device that consumes electricity (e.g., a light bulb).
6. Connecting Wires: To link all components.
7. Switch: To control the circuit.

Steps for Constructing the Model Transmission System

Follow these steps to build a basic model:

1. Connect the low-voltage power source (e.g., battery) to the primary coil of the step-up transformer.
2. Connect the secondary coil of the step-up transformer to the “transmission line” (long connecting wires).
3. Connect the other end of the transmission line to the primary coil of the step-down transformer.
4. Connect the secondary coil of the step-down transformer to the load (e.g., a light bulb in a holder).
5. Ensure all connections are secure and the circuit is complete.
6. Introduce a switch in the primary circuit of the step-up transformer to control power flow.

Working Principle of the Model

When the switch is closed:

1. The power source supplies low voltage to the step-up transformer.
2. The step-up transformer increases the voltage, and this high voltage (low current) is sent through the transmission line.
3. The step-down transformer receives the high voltage and reduces it to a lower, usable voltage.
4. The light bulb (load) receives this lower voltage and lights up, demonstrating the successful transmission of power.

Teaching Methods/Instructional Techniques

Demonstration, Practical Activity, Guided Practice, Discussion, Question and Answer, Explanation

Instructional Procedures

Step 1: Introduction

Time: 5 minutes

Teaching Skill: Engaging, Questioning

Teacher’s Activity: The teacher greets the students and asks them about how electricity gets to their homes. The teacher then introduces the topic of power transmission and the role of transformers.

Pupils’ Activity: Students respond to questions and listen attentively to the introduction.

Learning Point: Introduction to power transmission

Step 2: Explanation of Transmission Systems

Time: 7 minutes

Teaching Skill: Explanation, Visualisation

Teacher’s Activity: The teacher explains what an electrical transmission system is and why it is necessary to transmit power over long distances. The teacher uses diagrams to illustrate the concept.

Pupils’ Activity: Students listen, observe the diagrams, and ask questions for clarification.

Learning Point: Understanding transmission systems

Step 3: Role of Transformers in Transmission

Time: 7 minutes

Teaching Skill: Explanation, Illustrating

Teacher’s Activity: The teacher explains the specific roles of step-up and step-down transformers in minimizing power loss during transmission. The teacher revises the basic principles of transformers.

Pupils’ Activity: Students recall previous knowledge about transformers and understand their application in power transmission.

Learning Point: Transformers’ role in power

Step 4: Identifying Components for the Model

Time: 5 minutes

Teaching Skill: Identification, Demonstration

Teacher’s Activity: The teacher displays all the instructional materials (transformers, wires, bulbs, power source, etc.) and guides students to identify each component and state its purpose in the model.

Pupils’ Activity: Students identify the components and discuss their functions.

Learning Point: Model components identification

Step 5: Guided Construction of the Model

Time: 10 minutes

Teaching Skill: Guidance, Practical Demonstration

Teacher’s Activity: The teacher guides students, in groups, to carefully connect the components to construct the model transmission system, ensuring correct wiring and safety. The teacher demonstrates each step.

Pupils’ Activity: Students follow the teacher’s instructions, work in groups, and assemble the model transmission system.

Learning Point: Practical model construction

Step 6: Demonstration and Observation

Time: 4 minutes

Teaching Skill: Observation, Application

Teacher’s Activity: The teacher helps students to switch on the power supply to the constructed model and observe the light bulb lighting up. The teacher asks students to explain what they observe.

Pupils’ Activity: Students observe the model in operation and explain the observed phenomenon.

Learning Point: Model operation observation

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. List two key components of the model transmission system you constructed.
2. What is the function of the step-up transformer in power transmission?
3. Briefly describe how the model transmission system works.

Pupils’ Activity: Pupils answer orally and in writing.

Learning Point: Assessment of understanding

Step 8: Note-Taking

Time: 4 minutes

Teaching Skill: Guided Writing

Teacher’s Activity: The teacher guides pupils/students to copy the essential Board Summary notes on the construction and working of the model transmission system into their notebooks.

Pupils’ Activity: Pupils/students copy the notes carefully into their notebooks.

Learning Point: Recording lesson notes

Step 9: Conclusion

Time: 3 minutes

Teaching Skill: Summarizing, Reinforcement

Teacher’s Activity: The teacher briefly summarizes the lesson, emphasizing the importance of transformers in efficient power transmission and their real-world applications. The teacher addresses any remaining questions.

Pupils’ Activity: Students listen to the summary and ask final questions.

Learning Point: Reinforcement of concepts

Continuous Assessment/Further Study

Type: Homework/Project

Instruction: Individually or in pairs, research and draw a more detailed diagram of a national power grid, identifying where step-up and step-down transformers are typically located. Explain the purpose of each transformer in your diagram.

1. Draw a diagram of a typical power transmission network.
2. Label the power generation plant, transmission lines, and various substations.
3. Indicate the locations of step-up and step-down transformers.
4. Briefly explain why transformers are placed at those specific points.

Lesson Keywords

• Transmission System – A network for transporting electricity from generation to consumption points.
• Transformer – An electrical device that transfers electrical energy between two or more circuits through electromagnetic induction, usually for changing voltage levels.
• Step-up Transformer – A transformer that increases voltage and decreases current.
• Step-down Transformer – A transformer that decreases voltage and increases current.
• Power Loss – Energy dissipated as heat during electrical transmission, primarily due to resistance.

Differentiation

For students who grasp the concept quickly, encourage them to investigate the types of materials used for transmission lines and why. For students who need more support, provide pre-assembled parts or clearer step-by-step visual guides during the construction phase, and pair them with stronger students.

Suggested Lesson Videos

Search on YouTube for: “How power transmission works physics SS3” or “Model electricity transmission system”

Teacher Guide for Using This Lesson Plan

Before the lesson, ensure all components for the model transmission system are available, functional, and safe for student use. Arrange the classroom to facilitate group work and provide enough space for practical construction. Begin by engaging students with real-world examples of electricity supply. Guide them through the theoretical explanation of transmission systems and the critical role of transformers. During the practical construction phase (Step 5), circulate among groups, providing hands-on assistance and ensuring correct wiring. Emphasize safety precautions when dealing with electrical components, even low voltage ones. After the practical activity, allow students to observe the model’s operation and discuss their findings. The Board Summary should be copied after the practical demonstration and discussion, ensuring students have a clear understanding before recording the notes. Check for understanding through questions throughout the lesson and during the evaluation stage. For weaker learners, simplify the connections and provide more direct guidance. For faster learners, challenge them to explain the physics behind the transformer’s operation or suggest improvements to the model.