Class: Senior Secondary School 1 (SS1, SS 1, SSS1, SSS 1)
Term: Second Term
Week: 8
Age: 15 years
Duration: 45 minutes
Subject: Auto Mechanic Work
Curriculum Theme: Auto Mechanic Work
Previous Lesson: Steering Boxes Types and Functions.
Topic: ENGINE LUBRICATING AND COOLING SYSTEM – Friction and Lubrication Purpose
Subject Matter: meaning of friction, merits of friction, demerits of friction, purpose of lubricating system, oil passages, oil pump, oil filters, types of lubricants and application areas

Specific Objectives

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

Cognitive Domain:

Define friction and state its merits and demerits.
Explain the purpose of an engine lubricating system.
Identify the main components of an engine lubricating system.
List different types of lubricants and their application areas.

Affective Domain:

Appreciate the importance of proper lubrication in engine maintenance.
Develop an interest in understanding engine systems.

Psychomotor Domain:

Demonstrate the effect of friction and lubrication using sample surfaces.
Identify visual representations of lubricating system components.

Participate actively in class discussions regarding engine lubrication.

Reference Materials

The following resources were used in planning this lesson:

9 Years Basic Education Curriculum for Senior Secondary Schools.
State Unified Scheme of Work for Auto Mechanic Work (SSS 1).
Macmillan Senior Secondary Auto Mechanics Book 1.
https://www.autozone.com/repairinfo/repairguide/repairGuideContent.jsp?pageId=0900c152800a7b48
https://www.britannica.com/science/lubrication

Instructional Materials

The teacher will teach this lesson with the aid of:

Lubricants (e.g., engine oil, grease).
Sample surfaces (e.g., wood blocks, metal plates).
Charts showing engine lubrication system diagrams.
Whiteboard/blackboard and markers/chalk.

Rationale for the Lesson

This lesson helps pupils understand the fundamental concepts of friction and why lubrication is necessary in an engine. Understanding these principles enables pupils to appreciate the design and maintenance of engine systems, preventing wear and tear, and ensuring optimal performance in practical applications.

Prerequisite/Previous Knowledge

Pupils should have basic knowledge of simple machines and the concept of forces from their Junior Secondary School science classes.

Lesson Content/Board Summary

ENGINE LUBRICATING AND COOLING SYSTEM – Friction and Lubrication Purpose

Meaning of Friction

Friction is a force that opposes motion between two surfaces in contact. It converts kinetic energy into heat.

Merits of Friction

The following are the advantages of friction:

It enables walking and running without slipping.
It allows vehicles to move on roads and their brakes to work.
It holds objects in place (e.g., nails in wood, screws).
It enables gripping and holding objects.

Demerits of Friction

The following are the disadvantages of friction:

It causes wear and tear on moving parts, leading to damage.
It generates unwanted heat, which can damage machinery.
It wastes energy, reducing the efficiency of machines.
It produces noise.

Purpose of Engine Lubricating System

The main purpose of the engine lubricating system is to reduce friction between moving engine parts, thereby preventing wear, dissipating heat, and cleaning the engine components.

The specific purposes include:

Reducing friction between moving parts.
Cooling engine parts by carrying away heat.
Cleaning the engine by removing dirt and metal particles.
Sealing piston rings to prevent gas leakage.
Damping shock and noise between engine parts.
Preventing rust and corrosion of metal surfaces.

Components of the Lubricating System

The following are key components of an engine lubricating system:

Oil Sump/Pan: Stores the engine oil.
Oil Pump: Circulates oil under pressure throughout the engine.
Oil Pick-up Tube and Strainer: Draws oil from the sump, filtering out large particles.
Oil Passages/Galleries: Channels through which oil flows to various engine parts.
Oil Filter: Removes impurities and contaminants from the oil before it reaches engine parts.
Pressure Relief Valve: Controls oil pressure within the system.
Oil Pressure Gauge/Sensor: Monitors oil pressure and indicates it to the driver.

Types of Lubricants and Application Areas

Lubricants are substances used to reduce friction between surfaces. They can be classified based on their state:

Liquid Lubricants (Oils):
- Engine Oil: Used in internal combustion engines to lubricate moving parts like crankshafts, camshafts, pistons, and valves.
- Gear Oil: Used in transmissions, differentials, and gearboxes.
- Hydraulic Fluid: Used in hydraulic systems (e.g., power steering, brakes) for power transmission.
Semi-Solid Lubricants (Greases):
- Grease: A mixture of oil and a thickening agent, used where oil cannot be easily retained, such as wheel bearings, chassis components, and universal joints.
Solid Lubricants:
- Graphite and Molybdenum Disulphide: Used in high-temperature or extreme-pressure applications, or where liquid lubricants are impractical (e.g., locks, heavy-duty machinery).

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 rub their palms together, first dry and then with a drop of oil. The teacher then asks them to describe the difference they feel.
Pupils’ Activity: Pupils rub their palms together as instructed and describe the differences in resistance and heat generation.
Learning Point: Pupils observe and experience the concept of friction and the effect of lubrication.

Step 2: Explanation of Friction and its Effects

Time: 7 minutes
Teaching Skill: Explanation/Illustration
Teacher’s Activity: The teacher defines friction, explains its merits and demerits, relating them to everyday examples and engine operations. The teacher uses charts to illustrate these points.
Pupils’ Activity: Pupils listen attentively, ask questions, and take notes.
Learning Point: Pupils understand the meaning, advantages, and disadvantages of friction.

Step 3: Purpose of the Engine Lubricating System

Time: 7 minutes
Teaching Skill: Explanation/Discussion
Teacher’s Activity: The teacher explains the critical role of the lubricating system in an engine, detailing each purpose such as reducing wear, cooling, cleaning, and sealing. The teacher encourages pupils to suggest why each purpose is important.
Pupils’ Activity: Pupils contribute to the discussion and grasp the various functions of engine lubrication.
Learning Point: Pupils understand why lubrication is essential for engine longevity and performance.

Step 4: Components of the Lubricating System

Time: 7 minutes
Teaching Skill: Identification/Demonstration
Teacher’s Activity: The teacher uses diagrams and charts to point out and explain the function of key components of the lubricating system, such as the oil pump, oil filter, and oil passages. The teacher might show a physical oil filter if available.
Pupils’ Activity: Pupils identify the components on the charts and understand their individual roles.
Learning Point: Pupils can name and describe the function of major lubricating system components.

Step 5: Types of Lubricants and Application Areas

Time: 7 minutes
Teaching Skill: Classification/Illustration
Teacher’s Activity: The teacher explains different types of lubricants (liquid, semi-solid, solid) and provides examples for each, discussing their specific application areas within an automobile. The teacher shows samples of engine oil and grease.
Pupils’ Activity: Pupils differentiate between various lubricants and identify where each is used.
Learning Point: Pupils recognize different types of lubricants and their appropriate uses.

Step 6: Class Discussion and Question & Answer

Time: 2 minutes
Teaching Skill: Questioning/Facilitation
Teacher’s Activity: The teacher opens the floor for questions and facilitates a brief discussion to clarify any misunderstandings.
Pupils’ Activity: Pupils ask questions and participate in the discussion.
Learning Point: Pupils get their questions answered and reinforce their understanding.

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 friction in your own words.
Mention two merits and two demerits of friction.
State three purposes of an engine lubricating system.
List any three components of the engine lubricating system.
Give two examples of liquid lubricants and one example of a semi-solid lubricant.

Pupils’ Activity: Pupils answer orally and in writing.

Learning Point: Pupils demonstrate understanding of the lesson.

Step 8: Conclusion

Time: 3 minutes
Teaching Skill: Summarization/Assignment
Teacher’s Activity: The teacher summarizes the key points of the lesson, emphasizing the importance of lubrication for engine health. The teacher assigns homework: “Draw a simple diagram of an engine lubricating system and label three key components.”
Pupils’ Activity: Pupils listen to the summary and copy the homework assignment.
Learning Point: Pupils consolidate their learning and prepare for further study.

Lesson Keywords

Friction – A force that opposes motion between surfaces in contact.
Lubrication – The process of applying a substance to reduce friction and wear between surfaces.
Lubricant – A substance (e.g., oil, grease) used to reduce friction.
Oil pump – A component that circulates oil under pressure through the engine.
Oil filter – A device that removes impurities from engine oil.
Viscosity – A measure of a fluid’s resistance to flow.

Differentiation

For pupils who grasp concepts quickly, the teacher can provide additional questions on advanced lubrication concepts or ask them to research different types of engine oils. For pupils needing more support, the teacher will provide simplified diagrams, re-explain concepts using more practical examples, and offer one-on-one guidance during activity time.

Note for teachers using this lesson plan

Ensure that the practical demonstration of friction with oiled and dry surfaces is clear and safe. Visual aids like engine diagrams or actual components (if available) will greatly enhance understanding. Encourage pupils to ask questions and relate the concepts to vehicles they see daily.