# CBSE Class 8 Science Revision Notes Chapter 12

## CBSE Class 8 Science Revision Notes Chapter 12 – Friction

Friction is the resistance that any object encounters as it moves across or through a surface or another medium. Without frictional force, an object would either not start moving or, if it was already moving, would not stop. The Class 8 Chapter 12 Science Notes go into detail about the various aspects of friction that are experienced every day.

Students can access Class 8 Science Notes Chapter 12 from the Extramarks’ platform and perform better on test day.

The topics covered in Chapter 12 Friction of CBSE Class 8 Science are listed below.

1. Force of Friction
2. Factors Affecting Friction
3. Spring Balance
4. Friction: A Necessary Evil
5. Increasing and Reducing Friction
6. Wheels Reduce Friction
7. Rolling friction
8. Sliding friction
9. Static friction
10. Fluid Friction
11. Fluid

## Revision Notes for CBSE Class 8 Science Chapter 12

### Access CBSE Class 8 Science Chapter 12 – Friction Notes

Friction: When two surfaces of an object come into contact, a force that resists their relative motion is known as friction. The frictional force always acts in the opposite direction to the direction of the applied force.

What are the causes of friction?

Frictional force comes into play as a result of the imperfections on the surfaces of the objects coming into contact, which leads to the interlocking of minute irregularities between the two surfaces and the ploughing of harder surfaces into smoother surfaces.

Factors Affecting Friction:

Some of the factors that affect friction include:-

• The roughness of the surface
• The extent by which the two surfaces can be pressed together
• Nature of the surfaces coming in contact

Types of Friction:

The different types of friction are as follows:-

Static Friction

The force of friction acting on a body at rest is referred to as static friction. The applied force on the object is always equal to and in opposition to this force. Static friction is the force that is present when the body is just beginning to slide along the surface.

Sliding Friction

Sliding friction is the frictional force that prevents two surfaces from sliding past each other when they are in contact. In general, sliding friction is smaller than static friction.

Rolling Friction

When one body rolls over another body, there is a frictional force between the two surfaces known as rolling friction. Typically, the sliding frictional force is greater than the rolling frictional force.

Effects of Friction:

Friction generally has the following effects:-

• It generates heat.
• It is responsible for causing wear and tear in tyres.
• Its force always opposes motion.

• It is possible to write on paper because of the friction between a pen and paper.
• The resistance between our feet and the earth allows us to stand, walk, and run.
• The friction between the surface of the road and the tyres of our vehicles allows them to move along it without slipping.

However, some of the disadvantages of friction are:-

• Moving objects frequently stop or slows down as a result of friction.
• Machines waste energy by generating heat as a result of friction.
• Friction eventually leads to the wear and tear of moving parts in machinery, shoe soles, and car tyres.

## Class 8 Science Chapter Friction Notes

The chapter on friction is covered in detail in the Class 8 Science Chapter 12 Notes. These notes adhere to the revised CBSE board syllabus and are written by subject matter experts. Students will gain an edge and have an easier time studying this chapter if they prepare with these notes. They can access these Class 8 Science Chapter 12 Notes on Extramarks.

### Class 8 Science Chapter 12 Notes

Class 8 Science Chapter 12 Notes further assist students with accurate and error-free pointers for the chapter’s content. These revision notes will help them to identify key concepts.

Chapter 12 Science Class 8 Notes are very helpful for Class 8 Science students. Here’s why these notes are beneficial:

Chapter 12 Science Class 8 Notes were written by subject matter experts with a thorough understanding of the subjects covered in this chapter.

These notes follow CBSE standards and are error-free. As a result, students can rely on these notes to study for their exams.

These notes, which summarise the chapter, aid students in learning its content efficiently.

Students will be able to review all the topics covered in the chapter by consulting these notes in a lesser revision time without sacrificing the quality of their preparation.

Students can assess their understanding using these notes.

### 1. What are the different factors that impact friction?

The main friction-affecting factors discussed in class 8 chapter 12 Science notes are surface texture and contact between two surfaces.

The force of friction is significantly greater on an uneven surface. It implies that the object’s motion will be constrained and strained. On the other hand, a smooth surface would make it simple for an object to move over it.

Furthermore, movement becomes challenging when an object and surface are in contact and being pressed hard against one another. If there were no pressure, there wouldn’t be any limitations on the motion.

### 2. What does fluid friction mean?

Regarding media like air and water, there are fluids. The friction that results from an object moving through a fluid is referred to as fluid friction. Fluids resist any object moving through them, despite the fact that this resistance may not always be visible. For instance, the air creates resistance for an eagle as it soars through the sky.

### 3. What are the advantages of friction?

Walking on the road is not possible without friction. The lack of friction makes it almost impossible to walk on ice. It takes friction to keep a ladder against a wall. The ladder won’t be able to grip the wall without it. When a road is wet, a thin film of water forms on the surface, reducing friction and making driving very challenging. This makes it challenging for the driver to maintain control of the car on a slick road. All of these factors make friction very important and advantageous.

### 4. What do you mean by “friction” according to Chapter 12 Friction Class 8 Science?

The force that prevents an object from moving when it comes into contact with another object is known as friction. It happens when two surfaces come into contact with one another. The mechanical advantage of a machine is diminished as a result of friction. When we push a heavy box that is kept on the floor, for instance, there is friction between the floor’s surface and the bottom of the box.