CBSE Class 7 Science Exemplar Chapter 8: Wind, Storm and Cyclone NCERT Solutions

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NCERT Solutions PDF Class 7 PDF

This chapter delves into the fascinating phenomena of wind, storms, and cyclones, crucial topics in Class 7 Science. The NCERT Solutions for Chapter 8 provide clear explanations and step-by-step answers to help students grasp the underlying principles. Key concepts covered include the formation of sea breezes due to differences in air pressure, the effect of blowing air on pressure, and essential safety precautions during lightning. These solutions are designed to simplify complex ideas, making them accessible for young learners. By working through these problems, students can reinforce their understanding of atmospheric science and prepare effectively for their examinations, ensuring they can confidently answer questions related to weather patterns and safety measures.

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Quick info

BoardCBSE
ClassClass 7
SubjectScience Exemplar
Session2026
LanguageEnglish
TypeNCERT Solutions
ChapterChapter 8

Chapter summary

Chapter 8 of the CBSE Class 7 Science Exemplar focuses on wind, storms, and cyclones. The NCERT Solutions cover multiple-choice questions that test understanding of air pressure differences causing sea breezes, the impact of airflow on pressure, and crucial safety guidelines during lightning. These solutions aim to clarify the scientific principles behind these weather events and promote awareness of necessary precautions.

Learning outcomes

  • Understand the cause of sea breeze and its direction.
  • Explain how blowing air affects pressure.
  • Identify correct safety measures during lightning.
  • Relate air pressure to weather phenomena like wind.
  • Differentiate between safe and unsafe shelters during storms.

Topics covered

Paper topics

  • Wind
  • Storms
  • Cyclones
  • Sea Breeze
  • Air Pressure
  • Lightning Safety
  • Atmospheric Phenomena
  • Weather
  • Airflow
  • Pressure Differences

Important topics

  • Sea Breeze Formation
  • Air Pressure and Wind
  • Lightning Safety Precautions
  • Understanding Airflow Dynamics

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Questions and Solutions

Multiple Choice Questions

1. A fire alarm usually detects smoke in case of fire. Where should such an alarm be placed in a room?

(a) Near the door

(b) On the floor

(c) On any wall

(d) On the ceiling

Solution: The correct answer is (d) On the ceiling. Smoke rises with heated air. Placing the alarm on the ceiling ensures it detects smoke as soon as it reaches the highest point in the room, allowing for early warning.
2. Four schematic diagrams are shown in Figure 8.1 to depict the direction of sea breeze. Which of them gives the correct direction?

(a)

(b)

(c)

(d)

Solution: The correct answer is (c). During the day, land heats up faster than the sea. The air above the land gets heated and rises, creating a low-pressure area. Cooler, denser air from the sea then blows towards the land to fill this space, which is known as the sea breeze.
3. Figure 8.2 shows a child blowing air with a straw near the opening of another straw which has its other end in a soft drink bottle. It was observed that the level of the soft drink in the straw rises up as soon as air is blown over its open end. Which one of the following best explains the reason for rise in level of the drink?

Fig. 8.2

(a) Blowing of air decreases pressure over the opening of the straw.

(b) The straw of the soft drink bottle collapses when air is blown over its open end.

(c) Blowing of air warms up the air inside the straw.

(d) Blowing of air increases the pressure on the surface of soft drink in the bottle.

Solution: The correct answer is (a) Blowing of air decreases pressure over the opening of the straw. When air is blown rapidly across the top of the straw, it reduces the air pressure in that region. The atmospheric pressure acting on the surface of the soft drink in the bottle is now higher than the pressure above the straw, causing the liquid to be pushed up into the straw.
4. Following are precautions one must take in case a storm is accompanied by lightning.

(i) Do not take shelter under a tree.

(ii) Do not take shelter under an umbrella with a metallic end.

(iii) Do not take shelter in open garages, storage sheds, etc.

(iv) Do not take shelter in a bus in the open.

Which one of these is not correct?

(a) (i)

(b) (ii)

(c) (iii)

(d) (iv)

Solution: The statement that is not correct is (iv). While it is true that you should not take shelter under a tree or an umbrella with a metallic end, and open garages are also unsafe, a bus in the open actually provides a safe shelter during a lightning storm. The metal body of the bus acts as a Faraday cage, conducting the lightning safely around the occupants to the ground.

Common mistakes

  • Confusing the direction of land breeze and sea breeze.
  • Misunderstanding the relationship between air speed and pressure.
  • Not identifying all correct safety precautions during lightning.

Revision tips

  • Review the diagrams carefully to understand wind direction.
  • Focus on the explanation of air pressure changes.
  • Memorize the safety precautions for lightning storms.
  • Connect the concepts of heating and air movement to wind formation.

Practice MCQs

Q1. A fire alarm is designed to detect smoke, which rises with heated air. Where is the most effective place to install a fire alarm in a room to ensure early detection?

Q2. Which diagram correctly illustrates the direction of a sea breeze, where cooler air blows from the sea towards the land?

Q3. When a child blows air with a straw over the opening of another straw placed in a soft drink bottle, the liquid level rises. What is the primary reason for this phenomenon?

Q4. During a storm accompanied by lightning, several precautions are advised. Which of the following actions is NOT a recommended safety measure?

Frequently asked questions

What is the main concept explained in Chapter 8 of the Class 7 Science Exemplar?

Chapter 8 explains the concepts of wind, storms, and cyclones, including how sea breezes form due to air pressure differences and essential safety measures during lightning.

Why should a fire alarm be placed on the ceiling?

A fire alarm should be placed on the ceiling because smoke, which rises with heated air, will reach the ceiling first, allowing for earlier detection of a fire.

How does a sea breeze form?

A sea breeze forms because land heats up faster than the sea during the day. The warmer air over land rises, creating lower pressure, and cooler air from the sea blows towards the land.

What happens to the air pressure when air is blown rapidly over an opening?

Blowing air rapidly over an opening creates a region of lower air pressure compared to the surrounding atmosphere.

What are some important safety precautions during a lightning storm?

Important precautions include not taking shelter under trees or umbrellas with metal ends, and avoiding open garages. A vehicle like a bus offers protection.

Is a bus a safe place to be during lightning?

Yes, a bus in the open is considered a safe place during lightning because its metal body acts as a Faraday cage, protecting occupants from electrical discharge.

Important links

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