Class: Senior Secondary School 1 (SS1 / SSS 1)
Term: 1st Term
Week: 5
Age: 15 years
Duration: 45 minutes
Subject: Radio, Tv & Electronics
Curriculum Theme: Trade
Previous Lesson: Conductors, Insulators And Semi-Conductors: Insulating Materials.
Topic: CONDUCTORS, INSULATORS, AND SEMI-CONDUCTORS.
Subject Matter: Semi-conductors, Semi-conducting materials, Silicon, Germanium, Gallium arsenide

Specific Objectives

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

Cognitive Domain:

Define semi-conductors.
State the characteristics of semi-conductors.
Differentiate between conductors, insulators, and semi-conductors.
Mention examples of semi-conducting materials.

Affective Domain:

Appreciate the importance of semi-conductors in modern electronics.
Show interest in understanding how different materials behave electrically.

Psychomotor Domain:

Identify samples of semi-conducting materials like silicon wafers or germanium.
Draw a simple representation of a semi-conductor’s atomic structure.

Discuss the applications of semi-conductors in everyday devices.

Reference Materials

The following resources were used in planning this lesson:

9 Years Basic Education Curriculum for Radio, TV and Electronics.
State Unified Scheme of Work for Senior Secondary School Radio, TV and Electronics.
Electronics Technology for Schools and Colleges by F.N. Amaefule.
https://www.electronics-tutorials.ws/diode/diode_1.html
https://www.electrical4u.com/semiconductor/

Instructional Materials

The teacher will teach this lesson with the aid of:

Whiteboard and markers/chalk.
Diagrams showing atomic structures of conductors, insulators, and semi-conductors.
Samples of silicon wafer, germanium, and electronic chips.
Charts illustrating the energy band gap of different materials.

Rationale for the Lesson

This lesson helps pupils understand the basic electrical properties of different materials used in electronic devices. Knowing about conductors, insulators, and especially semi-conductors, is important for understanding how phones, computers, and other gadgets work, which are part of daily life.

Prerequisite/Previous Knowledge

Pupils have prior knowledge of basic electricity, atomic structure, and have been introduced to conductors and insulators in previous classes.

Lesson Content/Board Summary

CONDUCTORS, INSULATORS, AND SEMI-CONDUCTORS

Introduction to Conductors, Insulators, and Semi-conductors

Materials are classified based on their ability to conduct electricity. This ability depends on the availability of free electrons in their atomic structure.

Conductors: Materials that allow electric current to flow easily through them due to a large number of free electrons. Examples include copper, silver, and gold.
Insulators: Materials that do not allow electric current to flow easily through them because they have very few free electrons. Examples include rubber, plastic, and glass.

Semi-conductors

Semi-conductors are materials whose electrical conductivity lies between that of conductors and insulators. Their conductivity can be controlled by adding impurities (doping) or by changes in temperature and light.

Characteristics of Semi-conductors

The following are characteristics of semi-conductors:

They have four valence electrons in their outermost shell.
Their electrical conductivity increases with increasing temperature.
Their conductivity can be significantly altered by adding small amounts of impurities (doping).
They have a small energy band gap, allowing electrons to move to the conduction band with moderate energy.
They exhibit rectification properties when combined, allowing current to flow in one direction more easily than the other.

Examples of Semi-conducting Materials

The following are common semi-conducting materials:

Silicon (Si): The most widely used semi-conducting material. It is abundant and forms the basis of most modern electronic devices like microprocessors and solar cells.
Germanium (Ge): An older semi-conducting material, less common than silicon today, but still used in some specialized applications. It has a smaller energy band gap than silicon.
Gallium Arsenide (GaAs): A compound semi-conductor known for its high electron mobility, making it suitable for high-frequency and high-speed applications like microwave circuits and laser diodes.

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 know about materials that conduct electricity easily and those that do not. The teacher then introduces the topic: Conductors, Insulators, and Semi-conductors.
Pupils’ Activity: Pupils respond to questions about conductors and insulators and pay attention to the new topic.
Learning Point: Pupils recall previous knowledge and are prepared for the new lesson.

Step 2: Review of Conductors and Insulators

Time: 8 minutes
Teaching Skill: Explanation/Review
Teacher’s Activity: The teacher briefly reviews the definitions and properties of conductors and insulators, providing examples. This sets the context for introducing semi-conductors.
Pupils’ Activity: Pupils listen, ask questions for clarity, and contribute examples of conductors and insulators.
Learning Point: Pupils refresh their understanding of basic electrical material classifications.

Step 3: Definition of Semi-conductors

Time: 7 minutes
Teaching Skill: Explanation
Teacher’s Activity: The teacher defines semi-conductors as materials with conductivity between conductors and insulators. The teacher explains that their conductivity can be controlled.
Pupils’ Activity: Pupils listen attentively and write down the definition in their notes.
Learning Point: Pupils understand the basic definition of a semi-conductor.

Step 4: Characteristics of Semi-conductors

Time: 8 minutes
Teaching Skill: Explanation/Elaboration
Teacher’s Activity: The teacher explains the key characteristics of semi-conductors, such as having four valence electrons, increasing conductivity with temperature, and susceptibility to doping.
Pupils’ Activity: Pupils listen, take notes, and ask questions about the characteristics.
Learning Point: Pupils learn the distinguishing properties of semi-conducting materials.

Step 5: Examples of Semi-conducting Materials

Time: 7 minutes
Teaching Skill: Demonstration/Listing
Teacher’s Activity: The teacher presents and discusses common examples of semi-conducting materials: Silicon, Germanium, and Gallium Arsenide. The teacher may show samples like a silicon wafer or electronic chips.
Pupils’ Activity: Pupils observe the samples, note the examples, and listen to their brief descriptions.
Learning Point: Pupils identify specific materials that function as semi-conductors.

Step 6: Differentiation

Time: 5 minutes
Teaching Skill: Comparison/Analysis
Teacher’s Activity: The teacher facilitates a discussion comparing and contrasting the electrical properties of conductors, insulators, and semi-conductors, emphasizing their differences in conductivity and applications.
Pupils’ Activity: Pupils participate in the discussion, highlighting the differences between the three types of materials.
Learning Point: Pupils can differentiate between conductors, insulators, and semi-conductors based on their properties.

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 a semi-conductor.
State three characteristics of semi-conductors.
Mention two examples of semi-conducting materials.
How do semi-conductors differ from conductors and insulators?

Pupils’ Activity: Pupils answer orally and in writing.

Learning Point: Pupils demonstrate understanding of the lesson.

Step 8: Conclusion

Time: 2 minutes
Teaching Skill: Summarization
Teacher’s Activity: The teacher summarizes the main points of the lesson, reiterating the definition, characteristics, and examples of semi-conductors. The teacher then assigns homework, asking pupils to research the applications of silicon in electronic devices.
Pupils’ Activity: Pupils listen to the summary, ask any final questions, and note down the homework.
Learning Point: Pupils consolidate their learning and are given a task for further exploration.

Lesson Keywords

Conductor – A material that allows electric current to flow through it easily.
Insulator – A material that resists the flow of electric current.
Semi-conductor – A material with electrical conductivity between that of a conductor and an insulator.
Silicon – A common semi-conducting element used in many electronic devices.
Germanium – Another semi-conducting element, less common than silicon.
Gallium Arsenide – A compound semi-conductor used for high-speed applications.
Doping – The process of adding impurities to a semi-conductor to change its electrical properties.

Differentiation

For pupils who grasp concepts quickly, the teacher can provide additional questions on the energy band theory or specific applications of each semi-conductor. For pupils who need more support, the teacher can provide simplified diagrams and allow for peer-to-peer explanation or one-on-one guidance during activity time.

Note for teachers using this lesson plan

Ensure to have actual samples or clear visual aids of semi-conducting materials and electronic chips to make the lesson more practical and engaging. Encourage pupils to ask questions and relate the concepts to devices they use daily. Emphasize the unique characteristic of semi-conductors that makes them indispensable in modern technology.