Last Updated on July 21, 2020 by Alabi M. S.
BASIC SCIENCE AND TECHNOLOGY
THEME: YOU AND ENERGY
TOPIC – FORCE
1. Definition of Friction
2. Advantages and Disadvantages of Friction
3. Methods of Reducing Friction
By the end of the lesson, the students should have attained the following objectives (cognitive, affective and psychomotor) and should be able to –
1. explain the meaning of friction
2. state the advantages and disadvantages.
3. list the methods of reducing friction.
Oiling and greasing
The teacher will teach the lesson with the aid of:
1. Fixed door paper, spring, rubber
2. Charts showing contact and non – contact forces
3. Objects of known mass, meter – rule Newton – meter
4. Knife edge and slotted weights
5. Toy car, cardboard paper, rough surface.
METHOD OF TEACHING – Choose a suitable and appropriate methods for the lessons.
Note – Irrespective of choosing methods of teaching, always introduce an activities that will arouse pupil’s interest or lead them to the lessons.
1. Scheme of Work
2. 9 – Years Basic Education Curriculum
3. Course Book
4. All Relevant Material
5. Online Information – Forces – Meaning and Types of Forces (JSS 1)
CONTENT OF THE LESSON
In the school and at home, we see many moving things. We move about on our legs, vehicles move on roads, trains on the rails, aeroplanes fly in the sky and ships sail on the seas.
Movement occurs when a force is applied on a thing or object. That is, force causes things to move.
It can also prevent things from moving.
Friction is the force that opposes the motion of an object.
Friction can slow down or stops any moving objects.
ADVANTAGES OF FRACTION
Friction plays a vital role in our daily life. Without friction we are handicap.
1. It prevents slipping while walking.
2. It stops cars from moving.
3. We cannot fix nail in the wood or wall if there is no friction. It is friction which holds the nail.
4. A horse cannot pull a cart unless friction furnishes him a secure Foothold.
DISADVANTAGES OF FRACTION
Despite the fact that the friction is very important in our daily life, it also has some disadvantages like:
1. The main disadvantage of friction is that it produces heat in various parts of machines. In this way some useful energy is wasted as heat energy.
2. Due to friction we have to exert more power in machines.
3. It opposes the motion.
4. Due to friction, noise is also produced in machines.
5. Due to friction, engines of automobiles consume more fuel which is a money loss.
METHODS OF REDUCING FRICTION
There are a number of methods to reduce friction in which some are discussed here.
1. Use of Lubricants
The parts of machines which are moving over one another must be properly lubricated by using oils and lubricants of suitable viscosity.
2. Use of Grease
Proper greasing between the sliding parts of machine reduces the friction.
3. Use of Ball
Bearing In machines where possible, sliding friction can be replaced by rolling friction by using ball bearings.
4. Design Modification
Friction can be reduced by changing the design of fast moving objects. The front of vehicles and airplanes made oblong to minimize friction.
To deliver the lesson, the teacher adopts the following steps:
1. To introduce the lesson, the teacher revises the previous lesson. Based on this, he/she asks the students some questions;
2. Provides materials and direct illustration of frictional forces.
3. Initiates and leads discussion on advantages and disadvantages of friction.
Student’s Activities – Illustrate frictional force between objects, noting advantages and disadvantages of friction.
To conclude the lesson for the week, the teacher revises the entire lesson and links it to the following week’s lesson.
1. explain the meaning of friction.
2. state 4 advantages and 4 disadvantages of friction.
3. state 4 methods of reducing friction.