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Friction Class 8 Notes CBSE Science Chapter 12 (Free PDF Download)

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Last updated date: 22nd Mar 2024
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MVSAT 2024

Revision Notes for CBSE Class 8 Science Chapter 12 - Free PDF Download

Friction is essentially the resistance experienced by any object that is moving across or through a surface or medium, respectively. In the absence of frictional force, either movement of an object would not start or if in motion, would not come to a stop. Class 8 Science chapter 12 notes elaborate on the various aspects of friction that are seen in our everyday lives. Vedantu is a platform that provides free CBSE Solutions (NCERT) and other study materials for students. Maths Students who are looking for better solutions can download Class 8 Maths NCERT Solutions to help you to revise the complete syllabus and score more marks in your examinations.


Topics Covered in the Chapter 12 Friction of CBSE Class 8 Science

Students looking for notes on Chapter 12 Friction notes must know the topics covered in the syllabus. Below given are the topics covered in Chapter 12 Friction of CBSE Class 8 Science.

  1. Force of Friction

  2. Factors affecting Friction

  1. Spring Balance

  1. Friction: A Necessary Evil

  2. Increasing and Reducing Friction

  3. Wheels Reduce Friction

  1. Rolling friction

  2. Sliding friction

  3. Static friction

  1. Fluid Friction 

  1. Fluids


Download CBSE Class 8 Science Revision Notes 2023-24 PDF

Also, check CBSE Class 8 Science revision notes for other chapters:


Access CBSE Class 8 Science Chapter 12 - Friction Notes

1. Friction: The force that opposes the relative motion between two surfaces of objects when they come in contact. Frictional force always acts in a direction opposite to the direction of applied force.


2. What are the causes of Friction?

Frictional force comes into play between two surfaces due to irregularities on the surfaces of the objects coming in contact, causing interlocking of micro-level irregularities between the two surfaces and ploughing of harder surfaces into smoother surfaces.


Factors Affecting Friction:

a. The roughness of the surface is present.

b. The extent by which the two surfaces can be pressed together.

c. Nature of the surfaces coming in contact.


Types of Friction:

a. Static Friction: When a body is at rest, the force of friction acting on it is known as static friction. This force is always equal and opposite to the applied force on the object. The force which is acting, when the body is just at the point of sliding on the surface is known as limiting friction.

b. Sliding friction: The frictional force which opposes the sliding motion between two surfaces which are in contact. Sliding friction is generally smaller than static friction.

c. Rolling Friction: The frictional force which is present between the two surfaces when one body rolls over the other body. The rolling frictional force is usually smaller than sliding frictional force.


Effects of Friction:

a. Friction generates heat.

b. Friction is responsible for causing wear and tear in tyres. 

c. Frictional force always opposes motion.


Advantages of Friction:

a. It is due to friction between pen and paper which allows us to write on paper.

b. Frictional force between our feet and the ground allows our movements like standing, walking and running.

c. Frictional force between the surface of the road and tyres of our vehicles allows the vehicles to move on the road without slipping.


Disadvantages of Friction

a. Due to friction, moving objects tend to stop or slow down as their motion is opposed.

b. Due to friction heat is generated leading to wastage of energy in machines.

c. Friction is responsible for the wear and tear of moving parts of machinery, soles of shoes, and tyres on the road after some time.


3. Friction is a necessary evil. why? 

Friction has advantages so considered a friend but due also has some disadvantages,  then it is a foe. Depending on the circumstance, friction could be of help or could be a problem. Therefore, it is a necessary evil.


4. How can we Increase Friction?

a. We can increase friction by pressing the surfaces together very strongly. For example, when we apply brakes while riding a bicycle or car, the brake pads are pressed against a moving part of the wheel which leads to increased friction force.

b. Friction can also be increased by increasing the roughness of the surfaces which are coming in contact. For example, the threading of shoes and tires is done to increase friction which causes its movement on the road without slipping.


5. How can we reduce friction?

  1. Frictional force acting between the sliding surfaces of two objects can be reduced by making the surfaces in contact smooth by polishing them.

  2. Sliding friction between the moving parts of vehicles and machinery can be reduced by applying oil, grease, graphite or any other lubricant. The rolling frictional force is usually smaller than the sliding frictional force. Hence, sliding friction is generally replaced by rolling friction by using rollers, like ball bearings are used between the hub and the axles in the moving parts of machines and vehicles.

  3. Friction can be reduced by providing wheels, hence used in suitcases, and school bags of kids.


6. The body of aeroplanes, boats, fishes and birds are able to move through fluids because of their streamlined shape, in order to reduce the friction due to fluid and avoid any energy loss.


Class 8 Science Chapter Friction Notes – Free PDF Download

Class 8 Science ch 12 notes take a comprehensive approach in covering the chapter on friction. It specifically focuses on the topics that are important for CBSE board students. Preparing from this note will help the students to solve questions from this chapter with greater ease. The free PDF can be downloaded from the official website of Vedantu.


Class 8 Science Chapter 12 Notes

Chapter 12 Science class 8 notes discuss the following topics on friction:

  • Causes of Friction

Class 8 Science friction notes explain the main factors for production to be the roughness of the surface, the intensity with which two objects are pressed together, and the nature of the surface itself.


  • Different Types of Friction

Friction can be of various kinds:

  1. Static Friction: This frictional force is applicable when a body remains at rest. Static friction is equal, and opposite to the force applied, at all times. However, when the body is just on the verge of setting into motion, the force is called limiting friction.

  2. Sliding Friction: This force resists actual relative sliding motion.

  3. Rolling Friction: This frictional force comes into existence when one body rolls over another body. It should be noted in this regard that rolling friction will remain less than sliding friction.


  • Impact of Friction

A few of the main effects of friction as discussed in chapter 12 friction class 8 notes are:

  1. Production of heat.

  2. Causing wear and tear in an object.

  3. Offers resistance to an actual motion.


  • Benefits of Friction

The primary benefit of the frictional force is to enable objects to move. We can move over the ground or write on paper due to the existence of friction. Vehicles can move on the road because of the frictional force between tyres and the surface of the road. Friction prevents vehicles from slipping on the road.


  • Disadvantages of Friction

The disadvantages of friction are that it may slow down or stop the motion of objects, and also cause the generation of heat. Such heat can lead to energy wastage in machines. It can also cause wear and tear.


Benefits of Refereeing to Friction Chapter 12 Class 8 CBSE Science Notes 

These notes are very beneficial for Science students of Class 8. Some of the reasons for this have been listed below:

  • These notes are prepared by expert and experienced Science teachers and subject matter experts having in-depth knowledge of the topics covered in this chapter.

  • These notes are error-free and adhere to the CBSE standards. Hence, students can reliably refer to these notes while preparing for their exams. 

  • These notes include the gist of the chapter and help students to prepare even on the night before the exam. 

  • By referring to these notes, they will cover all the topics discussed in the chapter and thereby reduce their revision time considerably without compromising on their quality of preparation. 

  • With these notes, students can evaluate their understanding of the chapter and find the loopholes, if any. 

  • These notes follow the latest syllabus prescribed by the CBSE and cover important questions in Chapter 12 of the NCERT book. 

  • Students can easily download the PDF at no cost and study them offline too.

If you have started preparing the topic for examination, Class 8 Science Chapter 12 notes will further help you in the process. The revision notes will come in handy, and will help you to identify the important topics. If you have queries, those can be clarified in Vedantu's online classes. To know more, download the app on your preferred device.


When a matchstick is rubbed against the matchbox rough side, heat is produced because of the friction between the head of the matchstick and the matchbox rough side. The heat which was produced burns the chemicals which were present on the head of the matchstick. Due to this, the matchstick lights up. Then,  the matchstick catches fire and starts burning. If the surface of the matchstick is smooth, it becomes difficult to light a matchstick as enough friction does not occur by a smooth surface to produce heat.


Chapter-wise Revision Notes for Class 8 Science


Also access, 


Conclusion 

Vedantu students' studies about friction in CBSE Class 8 Science Chapter 12 is vital for understanding the fundamental forces that govern our daily lives. These notes provide a comprehensive overview of friction, its types, and its impact on various aspects of our world. They highlight its significance in our daily activities, such as walking, driving, and even sports. Furthermore, these notes underscore the importance of reducing friction in machinery and technology to enhance efficiency and minimize wear and tear. Moreover, these free PDF notes cater to CBSE students, ensuring that they have access to high-quality educational resources. Understanding friction is not only essential for academic success but also for practical applications in everyday life. By grasping the concepts presented in these notes, students can develop a deeper appreciation for the role of friction in our world and apply this knowledge to solve real-world problems. In essence, these CBSE Class 8 Science Chapter 12 notes on friction are a valuable resource for students seeking a well-rounded understanding of this fundamental force.

FAQs on Friction Class 8 Notes CBSE Science Chapter 12 (Free PDF Download)

1. What are the Different Factors that Impact Friction?

The major factors elaborated in class 8 chapter 12 Science notes that affect friction are – (1) surface texture, and (2) contact between two surfaces.


If the surface is irregular, the force of friction is significantly higher. It means that the movement of the object will be strained and restricted. On the other hand, if the surface texture is smooth, an object could easily move over that surface.


Moreover, when an object and surface are in contact, and both of those are pressed hard, again the movement becomes difficult. In the absence of pressure, there would be no restriction in movement.

2. What is Understood by Fluid Friction?

Fluids pertain to mediums like air and water. When an object moves through a fluid, there is resultant friction called fluid friction. Even though it may not be apparent, fluids exert resistance on any object moving through it. For instance, when an eagle is soaring in the sky, the air causes resistance to the bird.

3. What are the Major Drawbacks of the Frictional Force?

The disadvantages of frictional force have been discussed clearly in class 8 Science chapter 12 notes. A few of the major drawbacks are – (1) wear and tear of objects moving across a surface, (2) friction causes the production of heat leading to energy wastage, (3) frictional force is responsible for causing a reduction in speed of an object in motion.

4. What are the Various Types of Friction?

The different types of friction as mentioned in friction chapter notes class 8 include – (1) static friction, (2) rolling friction, (3) sliding friction, and (4) fluid friction.


Static friction relates to such force that remains operational until the point an object starts to move. Rolling friction, as the name suggests, is the force of friction experienced by an object when rolling on a surface. Sliding friction is the force exerted on an object when it moves across the surface of another object. Finally, fluid friction is the force exerted by air or water when an object moves through it.

5. Are the NCERT Solutions for Chapter 12 Friction Class 8 Science the best study material for the students?

The NCERT Solutions for Chapter 12 Friction Class 8 Science is the best study material for the students as it helps them to improve their conceptual knowledge. The solutions are accurate and are written by the subject experts of Vedantu according to the latest CBSE syllabus and guidelines. These solutions will help the students to gain a clear understanding of the concepts which are important for the exams. Most of the questions which appear in the board exams and competitive exams are derived from the NCERT textbooks. Students should regularly practice the textbook questions to improve their academic performance.

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

Friction is known as the force which always resists the motion of one object in contact with another object. It occurs between the two surfaces which are in contact with each other. It’s because of friction that the mechanical advantage of a machine is reduced. For example, the force of friction occurs between the surface of the floor and the bottom of the box when we push a heavy box that is kept on the floor.

7. What do you mean by lubricants? What is their use?

Lubricants are those substances that reduce friction. Friction should be reduced to increase efficiency. Friction can be reduced between the moving parts of a machine by applying oil, grease or graphite. Then a thin layer is formed there which makes the moving surfaces not directly rub against each other. In this way, the interlocking of irregularities is avoided to a maximum extent and movement becomes smooth. The three main types of lubricants are oil-based, water-based, and silicone-based.

These solutions are available on Vedantu's official website(vedantu.com) and mobile app free of cost.

8. What are the benefits of friction?

Without friction, it’s impossible to walk on the road. Walking on ice is almost not possible due to a lack of friction. To keep a ladder against a wall, friction is needed. Without it, the ladder won’t have a grip against the wall. It becomes very difficult to drive on a wet road as a thin film of water is created on the surface of the road which reduces the friction. Because of this, it becomes difficult for the driver to control the vehicle on a wet road. Because of all these, friction becomes very important and has many benefits. To understand more about Friction, visit Vedantu.

9. How does friction enable us to light a matchstick?

When a matchstick is rubbed against the matchbox rough side, heat is produced because of the friction between the head of the matchstick and the matchbox rough side. The heat which was produced burns the chemicals which were present on the head of the matchstick. Due to this, the matchstick lights up. Then,  the matchstick catches fire and starts burning. If the surface of the matchstick is smooth, it becomes difficult to light a matchstick as enough friction does not occur by a smooth surface to produce heat.