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NCERT Solutions for Class 8 Science Chapter 15 - Some Natural Phenomena

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Last updated date: 29th Mar 2024
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MVSAT 2024

NCERT Solutions for Class 8 Science Chapter 15 Some Natural Phenomena - Free PDF Download

The NCERT Solutions for Class 8 Science Chapter 15 - Some Natural Phenomena provides thorough answers to all questions in this chapter, making it a valuable resource for exam preparation when used alongside the textbooks. By delving into captivating natural events such as lightning, earthquakes, and thunderstorms, students gain insights into the scientific explanations, causes, and safety measures during these occurrences. These NCERT Solutions reduce the need to consult additional books for a well-rounded understanding.


You can also download NCERT Solutions for Class 8 Maths and NCERT Solutions for Class 8 Maths to help you to revise complete syllabus and score more marks in your examinations.


Class:

NCERT Solutions For Class 8

Subject:

Class 8 Science

Chapter Name:

Chapter 15 - Some Natural Phenomena

Content Type:

Text, Videos, Images and PDF Format

Academic Year:

2023-24

Medium:

English and Hindi

Available Materials:

Chapter Wise

Other Materials

  • Important Questions

  • Revision Notes

Access NCERT Solutions for Science class 8 Chapter 15 – Some Natural Phenomena

1. Which of the following cannot be charged easily by friction? 

(a) A plastic scale

(b) A copper rod 

(c) An inflated balloon 

(d) A woollen cloth 

Ans. (b) A copper rod

When insulating materials such as plastic scales, balloons, and woollen clothes rub against each other, they may become electrically charged. Charging by friction is used to charge only non-conducting materials (poor conductors of electricity). As copper is a highly conducting material, it cannot be charged easily by friction.


2. When a glass rod is rubbed with a piece of silk cloth the rod 

(a) And the cloth both acquire positive charge.

(b) Becomes positively charged while the cloth has a negative charge. 

(c) And the cloth both acquire negative charge. 

(d) Becomes negatively charged while the cloth has a positive charge.

Ans. (b) becomes positively charged while the cloth has a negative charge.

When an object is charged by rubbing it against another object, the two objects acquire opposite charges. By convention, it is considered that the charge acquired by the silk cloth is negative and the charge acquired by the glass rod is positive. Therefore, the glass rod becomes positively charged, whereas the silk cloth becomes negatively charged.

 

3. Write T against true and F against false in the following statements.

(a) Like charges attract each other.                                                                               

Ans. F

Like charges (positive-positive or negative-negative) repel each other, whereas unlike charges (positive-negative) attract each other.

(b) A charged glass rod attracts a charged plastic straw.                                             

Ans. T

Both objects have opposite charges on them. A charged glass rod (positively charged) attracts a charged plastic straw (negatively charged) because opposite charges attract each other.

(c) Lightning conductors cannot protect a building from lightning.                      

Ans. F

When lightning strikes, the lightning conductor conducts all of the atmospheric charges directly to the Earth, keeping the building safe. As a result, a lightning conductor protects a building against lightning strikes.

(d) Earthquakes can be predicted in advance.

Ans. F

Despite the fact that the causes of earthquakes are known, no instruments have been developed to detect them in advance. As a result, earthquakes cannot be predicted in advance.


4. Sometimes, a crackling sound is heard while taking off a sweater during winters. Explain. 

Ans. When we take off a sweater during winter, the woollen sweater gets charged due to friction between the body and the sweater. The discharge of these electric charges produces tiny sparks of light and a crackling sound.


5. Explain why a charged body loses its charge if we touch it with our hand. 

Ans. Electricity can flow through the human body because the human body is a conductor of electricity. When we come into contact with a charged object, our body conducts its charges to the Earth. That is why if we touch a charged body with our hand, it loses its charge. This is referred to as an electric discharge.


6. Name the scale on which the destructive energy of an earthquake is measured. An earthquake measures 3 on this scale. Would it be recorded by a seismograph? Is it likely to cause much damage? 

Ans. The Richter scale is used to determine how destructive an earthquake is. The scale ranges from one to ten. A seismograph would record a reading of magnitude 3 on the Richter scale.

If the earthquake has a magnitude of 3 on the Richter scale, it is unlikely to cause significant damage. Earthquakes of a magnitude greater than 5 are generally considered destructive in nature.


7. Suggest three measures to protect ourselves from lightning. 

Ans. Three protective measures against lightning are:

(i) Always remain in a covered area or stay indoors. If you are moving in a car, stay there until the lightning is over and keep the windows shut.

(ii) Do not bathe in running water during lightning.

(iii) Do not touch any electrical appliances, wires, telephone cables, metal pipes etc. during lightning.


8. Explain why a charged balloon is repelled by another charged balloon whereas an uncharged balloon is attracted by another charged balloon? 

Ans. A charged balloon repels another charged balloon because both carry the same type of charges and the same charges repel each other. 

When an uncharged balloon is brought near to a charged balloon, the uncharged balloon acquires the opposite charge on its surface by the process of induction. Thus, an uncharged balloon is attracted by another charged balloon because opposite charges attract each other.


9. Describe with the help of a diagram an instrument which can be used to detect a charged body. 

Ans. An electroscope is a device which is used to detect the charge on a body. It works on the principle that charges (positive-positive or negative-negative) repel each other while unlike charges (positive-negative) attract each other. 


Electroscope image


This device has a metal rod. At one end of the metal rod, two strips of aluminium foil are fixed and at the other end, there is a metal disc. The bottom of the rod and strips of aluminium foil are placed inside a conical flask for protection. When the metal disc of the electroscope is touched with a charged body (ebonite or glass rod), the aluminium strips diverge or move away from each other.  This happens because some of the charges of the charged body are transferred to the aluminium strips through the metal rod.  The nature of charges on both the aluminium strips is similar. Hence, both the strips of the aluminium foil move away from each other. If the body is not charged, then the two strips of aluminium remain as they are. They do not repel each other. 

The extent of divergence depends upon the amount of charge on the electroscope. When the aluminium strips repel each other proves that the body is charged because repulsion is the sure test to detect if the body is charged or not through an electroscope.


10. List three states in India where earthquakes are more likely to strike. 

Ans. The following are the three Indian states where earthquakes are more likely to occur:

(i) Jammu and Kashmir

(ii) Assam

(iii) Gujarat


11. Suppose you are outside your home and an earthquake strikes. What precaution would you take to protect yourself? 

Ans. If we are outside our home and an earthquake strikes, then the following precautions must be followed: 

(i) We should move to an open space away from tall buildings, tall trees, electric wires and poles.

(ii) If we are driving, we should slow down the vehicle and move it slowly to a clear spot away from buildings, electric poles, trees, etc. and stay there till the earthquake stops.


12. The weather department has predicted that a thunderstorm is likely to occur on a certain day. Suppose you have to go out on that day. Would you carry an umbrella? Explain.

Ans. In a thunderstorm, no one should carry an umbrella. Electric charges can travel from the cloud through the metallic rod of an umbrella during a thunderstorm accompanied by lightning. This could cause an electric shock to the person carrying it. As a result, carrying an umbrella during a lightning storm is dangerous.


NCERT Solutions for Class 8 Science Chapter 15 - Some Natural Phenomena

NCERT Solutions for Class 8 Science Chapter 15 – Free PDF Download

The fifteenth chapter of NCERT solutions of class 8 Science includes the solution to various natural phenomenons such as lightning, earthquake, charging by rubbing, etc. With assistance from this NCERT solution, students can get a clear understanding of these concepts.

There are a total of 7 sub-topics in this chapter, and it includes discussion on various natural spectacles. It includes the cause, effects, properties, and magnitude of lightning, functions of the electroscope etc. Practical examples and pictorial representation help candidates to comprehend a topic quickly.

NCERT Solutions for Class 8 Science Chapter 15 are an essential study material for students of class eight. Its use of simple and lucid language helps candidates to grasp any topic quicker. This NCERT solution is available online for free to download.

Topics Covered in Class 8 Chapter 15- Some Natural Phenomena

  1. Lightning

  2. Charging by Rubbing

  3. Types of Charges and Their Interaction

  4. Transfer of Charge

  5. The Story of Lightning

  6. Lightning Safety

  7. Earthquakes

Key Points Covered in This Chapter

  • Rubbing some things with other ones can charge them.

  • The two sorts of charges are positive and negative charges.

  • Charges with comparable charges repel one other, whereas charges with different charges attract each other.

  • An electric current is formed when charges move.

  • An electroscope can be used to determine whether or not a body is charged.

  • The process of transmitting charge from a charged object to the ground is known as earthing.

  • An electric discharge between clouds and the ground, or between clouds, causes lightning. Both persons and property can be damaged by a lightning strike.

  • Lightning conductors can be used to protect buildings from the effects of lightning.

  • An earthquake occurs when the earth suddenly shakes or trembles.

  • An earthquake is caused by a disturbance deep below the earth's crust.

  • It is impossible to anticipate when an earthquake will strike.

  • Earthquakes are most common at the earth's plate borders. Fault zones are the names given to these lines.

  • An earthquake of a magnitude of 7 or higher on the Richter scale can inflict significant damage to people and property.

  • To protect ourselves from earthquakes, we should take the required precautions.

NCERT Class 8 Science Chapter 15 Topic-Wise Discussion

The chapter of some natural phenomena Class 8 has seven sections. Here is a brief idea about each of them :

1. Lightning

After a generic introduction, the Ch 15 Science Class 8 begins with a discussion about lightning. It describes what lightning is and how it is perceived in recent times compared to ancient times. It further encourages students to perform a home-made experience to learn how electric charge is associated with lightning.

2. Charging by Rubbing

This sub-topic in Class 8 Science Chapter 15 talks about how electric charge is produced by rubbing two objects together. It uses an activity to urge students to understand this natural phenomenon. With the help of this activity, they can experience it first-hand and comprehend the topic better.

3. Types of Charges and their Interaction

This topic takes the discussion on charges a step further. In this sub-topic of NCERT Solutions Class 8 Science Chapter 15, students will learn how two similar charges are not attracted to each other. There are two activities that candidates can perform at their home to understand this concept better. In one experiment, students can use two inflated balloons and rub them with a woollen cloth. Once finished, they will observe that both of them are not coming together.

4. Transfer of Charge

This section in NCERT solution Class 8 Science Chapter 15 shows how metal can transfer charge. In the activity mentioned here, students can use a paperclip, empty refill of a ball pen, and two strips of aluminium foil to learn more about this concept. Also, they get to know about electroscopes, a device used to check whether an object is carrying charge or not.

5. Story of Lightning

NCERT solutions for Class 8 Science Chapter 15 Some Natural Phenomena further talks about the concept of lightning and the story behind it. Even though not fully discovered, researches have shown how positive and negative charges present in clouds cause this phenomenon. Before a thunderstorm, the air currents move upwards, and the water droplets move downward. It separates the currents. When the accumulation of these charges becomes high, it causes the lightning or electric discharge.

6. Lightning Safety

In this section of NCERT Solutions for Class 8 Science Chapter Some Natural Phenomena students learn about the necessary safety measures during thunderstorms and lightning. It includes the places that are safe during such situations, and the do’s and does not. This section further discusses light conductors and their importance in protecting buildings.

7. Earthquake

The last sub-topic in these NCERT solutions for Class 8 Science Ch 15 includes a detailed discussion about earthquakes. It is a complicated and highly unpredictable natural phenomenon. However, with the help of modern equipment, earthquakes can be predicted to a certain extent. This sub-topic then explains the definition and causes of an earthquake and how one can stay safe during this natural phenomenon.

4 Reasons to Study NCERT Solutions for Class 8 Science Chapter Some Natural Phenomena

As mentioned above, NCERT Solutions for Class 8 Science Chapter 15 offers a helping hand to the students and improves their preparations. Apart from that here are 4 reasons to opt for this study material –


1. CBSE Aligned: The solution aligns with CBSE's curriculum, ensuring answers are in the CBSE format, and facilitating exam preparation.


2. Student-Friendly Language: The use of simple language aids in easy comprehension, making even challenging topics accessible to students.


3. In-Depth Clarity: Detailed explanations assist candidates in understanding the fundamentals of each topic thoroughly, providing essential information.


4. Real-Life Relevance: The inclusion of real-life examples in the Some Natural Phenomena Class 8 NCERT helps students easily relate to and understand various topics.


NCERT Solutions for Class 8 Science Chapter 15 act as a helping hand to the students and improve their performance. This study material is available online for free. One can quickly download it from the website of Vedantu – one of India’s largest e-learning platforms. Additionally, Vedantu offers live sessions for doubt clearance to aid students further.

Chapter Wise NCERT Solutions for Class 8 Science

Along with this, students can also view additional study materials provided by Vedantu, for Class 8 :


Conclusion

NCERT Solutions plays a crucial role in Class 8 exam prep. Start by thoroughly reading the textbook chapter. After that, solve the NCERT questions for Class 8 Science Chapter 15 - Some Natural Phenomena. You can find detailed solutions on Vedantu, aligning with CBSE guidelines. Download the free NCERT Solutions for Class 8 Science Chapter 15 - Some Natural Phenomena to guide your exam preparation with expert-reviewed answers.

FAQs on NCERT Solutions for Class 8 Science Chapter 15 - Some Natural Phenomena

1. What are the benefits of NCERT solutions available online?

NCERT solutions are available online to help students to improve their exam preparations. These solutions are prepared by experts and follow the curriculum drafted by CBSE. The simple language and in-depth explanation of every topic help students to get a better understanding of the concepts. It offers better clarity of the subject, and students can improve their basic knowledge of a particular chapter. Also, the answers are accurate and to the point, which aid students to improve their preparations.

2. What are the three destructive natural phenomena according to Chapter 15 of Class 8 Science?

Cyclones, earthquakes, and lightning are the three major destructive phenomena. They have the capacity to cause severe damage and displace human habitats. Human life is also at stake during the occurrence of those destructive phenomena. To safeguard lives and provide humanitarian relief, adequate steps need to be taken to minimise the damage caused by these natural calamities. These steps have been discussed in detail on Vedantu.

3. What do you mean by natural phenomena according to  Chapter 15 of Class 8 Science?

Natural phenomena are those that occur in nature without any human interference. Through the course of Chapter 15 of NCERT Class 8 Science, seven sub-topics are discussed in depth. These include the causes, effects, properties, and magnitude of some destructive natural phenomena like lightning and earthquakes. Functions of the electroscope are discussed and some steps to minimise the damage caused by these disastrous events are dealt with.

4. What is the name for the natural phenomenon taking place due charging by induction according to  Chapter 15 of Class 8 Science?

In the process of induction, a charged object is brought near to but not touched to a neutral conducting object. When the object gets charged by induction, a reversal in the nature of charges occurs. A natural phenomenon that occurs due to the principle of induction is lightning. Electric discharge leads to the formation of streaks of bright light and the generation of loud sound.

5. What is discharge according to  Chapter 15 of Class 8 Science?

Lightning is an example of electric discharge. We have seen that the positive charges collect near the upper edges of the clouds while the negative charges accumulate near the lower edges. When the magnitude of the accumulated charges becomes very large, the surrounding medium containing air is no longer able to resist their flow. This leads to electric discharge or lightning. 

6. Where can I download NCERT Solutions for  Chapter 15 of Class 8 Science?

You can download NCERT Solutions for Chapter 15 of Class 8 Science on Vedantu. In case you are looking for chapter-wise solutions specifically, those are also readily available on Vedantu’s website as well. It comes as no surprise why most students prefer to use Vedantu to enhance their preparation before exams. The solutions are free of cost and also available on the Vedantu Mobile app.