NCERT Solutions for Class 7 Science Chapter 8: Winds, Storms and Cyclones
Chapter 8 is about winds, storms, and cyclones. Students learn about the effects of cyclones on agriculture, communication, natural resources and other aspects. Origin of storm, and wind currents are some other topics covered in the chapter.
NCERT Chapter 8 also has a practise exercise at the end so that students can revise the concepts they have learned. Extramarks provides NCERT Solutions for Class 7 Science Chapter 8 to help students solve practise exercise questions accurately.
The solutions have been prepared by the subject matter experts at Extramarks who follow the latest CBSE guidelines. These solutions have all the answers to the NCERT textbook questions solved in a step-by-step manner, and explained with relevant examples, wherever required.
NCERT Solutions for Class 7 Science Chapter 8
Access NCERT Solutions for Class 7 Science Chapter 8 – Winds, Storms, and Cyclones
NCERT Solutions for Class 7 Science Chapter 8
The NCERT Solutions for Class 7 Science Chapter 8 by Extramarks help students in preparing for exams in a better manner. The answers are written in simple and easy language making it easier for students to understand the concepts and the important points easily and make them revise quickly.
Introduction
Chapter 8 of the Class 7 Science syllabus deals with the concepts of winds, storms, and cyclones. In this chapter, students learn how cyclones adversely affect the natural resources, agricultural activities, transport, communication, accommodations, and electric supply of a particular area. Students will study the definition of cyclones, the reasons behind cyclones, the definition of storms, and where does a storm originate from?
8.1 Air Exerts Pressure
Activity 8.1 is an experiment to show that air exerts pressure. While rowing a boat, one feels that the wind comes from behind because the wind pressure helps the boat row faster. The concepts involve many examples which we experience in our everyday life. The Class 7 students need to study the topics with time and care with reference to NCERT Class 7 Science Chapter 8 solutions.
8.2 High-Speed Winds are Accompanied by Reduced Air Pressure
Class 7 students have already studied how air moves from one place to the others, especially; from the high air pressure region to the low air pressure region. The bigger the pressure difference, the faster the air will move from high to low pressure. The activity illustrates various experiments to make the students understand that high wind speed is always a result of low air pressure. Students need to perform all the experiments under the guidance of their mentors for safety reasons.
8.3 Air Expands on Heating
Activity 8.3 deals with the theory that air expands and takes up more spaces when it becomes hot. When an element occupies more space, it becomes lighter. Therefore, we know that hot air is lighter than cold air. Let us understand the concept with a simple example. When you light up a lamp, the flame always rises upwards. The reason is the fire is warmer than the surrounding cold air. Students can learn the theories at ease with these simple examples.
8.4 Wind Currents are Generated Due to Uneven Heating on the Earth
The section includes two activities;
- Uneven heating between the Equator and the Poles:
Everyone knows that regions located near the equator receive the maximum heat from the Sun. The warm air blows through these places. When the hot air in these places rises, the cold air from the polar regions enters and takes its place. This is how the wind circulation passes from the poles to the warmer regions. Students need to study the diagram to understand the topics in-depth.
- Uneven heating between land and water
Similarly to the first one, the land warms up faster than the water. The wind temperature of land is always higher than that of water. For this reason, the air blowing over the land becomes heated and rises high. Simultaneously, the cold wind enters the land from the ocean. Then, the wind brings rain. The students can get more information about the winds which cause rain. The section is vital from the examination point of view.
8.5 Thunderstorm and Cyclones
Thunderstorms and cyclones are interconnected. The rising wind is often the result of high temperatures at any place. The winds carry water droplets most of the time. The droplets freeze and come downwards. The movement of the water droplets from the sky to the ground with rising air creates light and sound in nature. We call this natural phenomenon a thunderstorm.
The second section deals with the cyclone. Students learn about how thunderstorms result in cyclone. The students learn about the storm, its formations, and its causes.
8.6 Destruction Caused by Cyclones
Cyclones are catastrophic. It has different names in different parts of the world, for example, typhoons and hurricanes. Students learn about tornados in this section. A tornado is a funnel-shaped, dark cloud that extends from the sky to the ground. Sometimes tornadoes are formed within cyclones.
8.7 Effective Safety Measures
It teaches students about the safety measures for protection. When destructive storms and cyclones occur, this piece of information comes in handy. The safety measures include:
- Do not ignore the warnings from the meteorological department via electronic and print media.
- Keep the most necessary household items and an emergency kit ready in place in case you have to move on short notice.
- Store dry food items and drinking water.
- Do not touch electric lines or switches.
- If possible keep your mobile and other electronic devices charged. Maintain a hard copy of all the emergency numbers.
- Do not step out. Stay indoors.
- Be agile and alert. Try to help others.
8.8 Advanced Technology has Helped
Nowadays, advanced technology helps us to be safe and protected from natural calamities. The weather forecast within 48 hours and constant updates by various media enable people to take appropriate action and stay safe.
Key Features of NCERT Solutions for Class 7 Science Chapter 8
The key features of NCERT Solutions for Class 7 Science Chapter 8:
- Subject matter experts prepare the solutions.
- Solutions are made as per the latest CBSE guidelines.
- The answers are written in detail and in simple language.
Q.1 Fill the missing word in the blank spaces in the following statements:
(a) Wind is —————— air.
(b) Winds are generated due to —————— heating on the earth.
(c) Near the earth’s surface __________ air rises up whereas ___________ air comes down.
(d) Air moves from a region of ——— pressure to a region of ——— pressure.
(a) Wind is moving air.
(b) Winds are generated due to uneven heating on the earth.
(c) Near the earth’s surface hot air rises up whereas cool air comes down.
(d) Air moves from a region of high pressure to a region of low pressure.
Q.2 Suggest two methods to find out wind direction at a given place.
The direction of wind can be found by following two methods:
1. Hold a small piece of cloth and raise your hand high in the air. The cloth will flow in the direction of the wind.
2. Pick some sand in your fist and allow it to fall slowly. The direction of fall of sand is same as that of the wind. This method of determining the direction of wind is widely used in desert areas by the travellers.
Q.3 State two experiences that made you think that air exerts pressure (other than those given in the text).
The experiences which show that air exerts pressure are as follows:
1. Blowing air in a balloon exerts pressure on its walls and causes it to inflate.
2. Paper bits spread on a cardboard moves and show displacement when air is blown over them.
Q.4 You want to buy a house. Would you like to buy a house having windows but no ventilators? Explain your answer.
One should not buy a house having windows but no ventilators because this interrupts cross-ventilation in the house. Cool fresh air enters the house through windows while dispensed heated air generated due to various human activities like, cooking, breathing etc; is removed through ventilators. Heated air being light rises up towards the roof and takes route through ventilators towards outside.
Q.5 Explain why holes are made in hanging banners and hoardings.
Holes are made in hanging banners and hoardings in order to equalise the air pressure on both sides of them. Higher pressure on one side of the hanging banners and hoardings may blow or torn them away when wind blows from one side at a high speed. Presence of holes allows air to pass through and prevents building up high pressure on one side.
Q.6 How will you help your neighbours in case cyclone approaches your village/town?
In case of cyclone approaching our village or town, we can help our neighbours in following ways:
1. Making them aware of the warnings issued by the meteorological department through TV, radio, or newspapers.
2. Advising them to choose safer places to shift whenever necessary and make arrangements to move essential household goods, domestic animals and vehicles, etc.
3. Circulating the phone numbers of all emergency services like police, fire brigade and hospitals to all.
4. Asking them to avoid travelling on roads with standing water, as floods might have damaged the roads.
5. Storing sufficient amount of drinking water and eatables for emergencies.
6. Extending cooperation to all for meeting the state of emergency.
Q.7 What planning is required in advance to deal with the situation created by a cyclone?
Given steps should be followed in advance to deal with the situation created by a cyclone:
1. An efficient weather forecast and warning system should be in place for timely action.
2. Rapid communication systems like, TV, radio etc, should be geared up for giving warnings to government agencies, ports, ships and fishermen in advance.
3. Cyclone management centres should be constructed in cyclone prone areas.
4. Rescue teams should be formed in advance for rapid shifting of people to safer places.
5. Safe drinking water and eatables should always be kept stored for providing relief in emergencies.
Q.8 Which one of the following place is unlikely to be affected by a cyclone.
(i) Chennai
(ii) Mangaluru (Mangalore)
(iii) Amritsar
(iv) Puri
Correct option is (iii).
Explanation:
Indian coastline regions are most vulnerable to cyclones.
Q.9 Which of the statements given below is correct?
(i) In winter the winds flow from the land to the ocean.
(ii) In summer the winds flow from the land towards the ocean.
(iii) A cyclone is formed by a very high-pressure system with very high-speed winds revolving around it.
(iv) The coastline of India is not vulnerable to cyclones.
The correct statement is:
(i) In winter the winds flow from the land to the ocean.
FAQs (Frequently Asked Questions)
1. Where will I find the chapter-wise Class 7 Science Solutions?
You will find the chapter-wise Class 7 Science solutions on Extramarks.
2. What is the Class 7 Science Chapter 8 about?
Class 7 Science Chapter 8 is about wind, storms, and cyclones.
