Question Answers for Chapter 2 Understanding the Weather Class 7 Social Science Exploring Society: India and Beyond
Class 7 Social Science Understanding the Weather Extra Questions
Very Short Answer Questions
Question 1. What is the standard atmospheric pressure at sea level?
Answer
1013 millibars.
Question 2. Name the instrument used to measure humidity.
Answer
Hygrometer.
Question 3. In which Indian city was an AWS set up in 2023 at over 4800 meters?
Answer
Sikkim.
Question 4. What is weather?
Answer
Weather is the condition of the Earth's atmosphere at a specific time and place.
Question 5. Which layer of the atmosphere is responsible for all weather changes?
Answer
The troposphere is the layer where all weather changes occur.
Question 6. How thick is the troposphere at the poles?
Answer
The troposphere is about 6 kilometres thick at the poles.
Question 7. Why do people in different regions experience weather differently?
Answer
People experience weather differently depending on their regional temperature, humidity, rainfall, and seasonal patterns.
Question 8. What type of clothes do people wear in winter?
Answer
People wear warm clothes during winter to protect themselves from the cold.
Question 9. How did people in earlier times predict rain using nature?
Answer
People observed signs like clouds, wind direction, and animal behaviour to predict rain.
Question 10. Which instrument is used to measure temperature?
Answer
A thermometer is the instrument used to measure temperature. It indicates how hot or cold the air is.
Question 11. What does a rain gauge measure?
Answer
A rain gauge measures the amount of rainfall in millimeters.
Question 12. What does atmospheric pressure mean?
Answer
Atmospheric pressure is the weight of air pressing down on the Earth's surface.
Question 13. Where is atmospheric pressure lower: mountains or sea coasts?
Answer
Atmospheric pressure is lower in mountains compared to sea coasts where air is thinner.
Question 14. What causes breathlessness at high altitudes?
Answer
Breathlessness at high altitudes is caused by thin air and low oxygen levels.
Question 15. What does an anemometer measure?
Answer
An anemometer measures the speed of the wind in kilometers per hour.
Question 16. Which instrument tells the direction of the wind?
Answer
A wind vane shows the direction from which the wind is blowing.
Question 17. What is humidity?
Answer
Humidity is the amount of water vapour present in the air.
Question 18. What happens to evaporation when humidity is high?
Answer
High humidity slows down the rate of evaporation.
Question 19. Which instrument is used to measure humidity?
Answer
A hygrometer is used to measure the amount of humidity in the air.
Question 20. How is snowfall measured in terms of precipitation?
Answer
Snowfall is measured by melting it first before using a rain gauge for accurate assessment.
Question 21. What is an Automated Weather Station (AWS)?
Answer
An Automated Weather Station is a system that measures weather data using sensors without human help.
Question 22. Who is responsible for issuing weather warnings in India?
Answer
The India Meteorological Department (IMD) is responsible for issuing weather warnings in India.
Short Answer Questions
Question 1. Define weather and name two elements used to describe it.
Answer
Weather is the condition of the Earth’s atmosphere at a specific time and place. Two elements are:
- Temperature
- Precipitation.
Question 2. What is the troposphere, and why is it important for living things?
Answer
The troposphere is the lowest layer of the atmosphere where all weather occurs. It is important because it supports all plants, animals, and humans.
Question 3. What is atmospheric pressure, and how does it vary with altitude?
Answer
Atmospheric pressure is the weight of air pressing down on Earth’s surface. It is higher near sea coasts and lower in mountains where air is thinner.
Question 4. Why are weather predictions important?
Answer
Weather predictions help people prepare for natural events like storms, droughts, or heat waves and ensure safety in fields like farming, aviation, and disaster management.
Question 5. How does atmospheric pressure affect mountaineers?
Answer
At high altitudes, pressure drops and oxygen becomes scarce, causing breathlessness for mountaineers and soldiers.
Question 6. How does weather influence the daily life of people?
Answer
Weather affects the clothes we wear, the food we eat, and even the activities we do. For example, people wear warm clothes in winter and cool clothes in summer.
Question 7. What role do meteorologists play in predicting weather?
Answer
Meteorologists collect data from weather instruments and use scientific methods to forecast weather. Their predictions help in disaster preparedness and planning.
Question 8. Why is the troposphere important in understanding weather?
Answer
The troposphere is where all weather changes occur, including rain, wind, and snow. It contains the air we breathe and supports life on Earth.
Question 9. How do high altitudes affect atmospheric pressure and human health?
Answer
At high altitudes, air pressure is lower and oxygen levels are lower, causing breathlessness. This makes it harder for people like mountaineers or soldiers to breathe easily.
Question 10. What is the use of a digital thermometer in weather measurement?
Answer
Digital thermometers give precise temperature readings and can store data. They help scientists track temperature changes accurately throughout the day.
Question 11. How do changes in air pressure lead to storms or cyclones?
Answer
Low air pressure can form a depression, which leads to stormy conditions or cyclones. These systems bring strong winds and heavy rainfall.
Question 12. What are some signs in nature that help predict the weather?
Answer
Animals and plants show signs like birds flying low or pine cones closing, which can indicate rain. These traditional signs are still used, especially in rural India.
Question 13. Why does high humidity make us feel uncomfortable?
Answer
High humidity reduces the evaporation of sweat, making us feel hotter and sweatier. It also makes clothes dry slower and causes stickiness.
Question 14. How does weather forecasting help farmers?
Answer
Farmers use weather forecasts to decide when to plant or harvest crops. Knowing about rainfall or heatwaves in advance helps protect their fields and animals.
Question 15. What is the meaning behind IMD’s motto, “From the sun arises rain”?
Answer
The motto “From the sun arises rain” means that the heat of the sun starts the water cycle. It explains that heat from the sun causes water to evaporate and form rain clouds. It highlights the sun’s role in driving the water cycle.
Question 16. Define weather and explain where most weather phenomena occur.
Answer
Weather is the state of the Earth's atmosphere at a particular time and place, described by elements like temperature, precipitation, humidity, wind, and atmospheric pressure. Most weather phenomena occur in the troposphere, the layer of the atmosphere closest to the Earth's surface, extending 6 to 18 kilometres from the ground.
Question 17. What is relative humidity, and what is its range in humid weather?
Answer
Relative humidity is the measure of the amount of water vapour present in the air compared to the maximum it can hold, expressed as a percentage. In humid weather, relative humidity typically ranges between 60% and 80%.
Question 18. Explain the purpose of a rain gauge and how it works.
Answer
A rain gauge measures the amount of rainfall in a specific area. It consists of a funnel that collects rainwater, which flows into a cylinder with a scale to measure the depth of the water in millimetres. For example, 5 mm of water collected indicates 5 mm of rainfall.
Question 19. How do traditional methods of weather prediction differ from modern methods?
Answer
Traditional methods of weather prediction rely on observing natural signs, such as birds flying low, ants moving eggs, frogs croaking, or pine cones opening and closing, to forecast events like rain or storms. These methods, passed down through generations, are based on experience and local knowledge. Modern methods, however, use scientific instruments like thermometers, barometers, and automated weather stations to collect precise data on weather elements. Meteorologists analyse this data to make accurate predictions, especially for extreme weather events like cyclones or droughts, using advanced technology and statistical models.
Question 20. Describe the role of a weather station in monitoring weather conditions.
Answer
A weather station is a system that combines instruments like thermometers, rain gauges, barometers, anemometers, and hygrometers to measure weather elements such as temperature, precipitation, atmospheric pressure, wind, and humidity. It takes regular readings to track weather changes, and automated weather stations (AWS) use sensors to record data without human intervention. This data helps in mapping, monitoring, and forecasting weather, supporting fields like agriculture, aviation, and disaster management.
Question 21. Why is it important to measure atmospheric pressure, and what instrument is used for this purpose?
Answer
Measuring atmospheric pressure is crucial because it indicates weather changes, such as the formation of low-pressure systems that can lead to storms or cyclones. It also affects human activities, like aviation and mountaineering, as pressure decreases with altitude, impacting oxygen availability. The instrument used to measure atmospheric pressure is a barometer, which typically displays pressure in millibars (mb), with normal sea-level pressure around 1013 mb.
Long Answer Questions
Question 1. Discuss the importance of weather predictions and the role of the India Meteorological Department (IMD) in India.
Answer
Weather predictions are very important, especially as extreme events like heavy rain, storms, droughts, and heat waves are becoming more common due to climate change. These predictions help in:
- Warning fishermen about stormy seas
- Evacuating coastal areas before cyclones
- Helping the government prepare disaster resources, which saves lives and property
The India Meteorological Department (IMD), set up in 1875, plays a major role in weather forecasting. For example, it issued a heat wave and severe weather alert on 19 May 2024.
IMD uses data from weather stations and applies scientific methods to predict weather. It supports many groups like:
- Farmers – to plan farming activities
- Pilots and sailors – for safe travel
- Policymakers – to make informed decisions
The IMD’s motto is “From the sun arises rain,” showing the sun’s importance in weather and reflecting its mission to ensure safety and better planning across India.
Question 2. Describe the five main elements of weather and how each is measured.
Answer
The five main elements of weather are:
- Temperature: How hot or cold the air is, measured using a thermometer in Celsius (°C) or Fahrenheit (°F).
- Precipitation: Water falling as rain, snow, sleet, or hail, measured with a rain gauge in millimeters (e.g., 5 mm of rainfall).
- Atmospheric Pressure: The weight of air pressing down, measured with a barometer in millibars (mb), e.g., 1013 mb at sea level.
- Wind: Air movement, measured for direction with a wind vane and speed with an anemometer in km/h.
- Humidity: Water vapor in the air, measured as relative humidity (0–100%) with a hygrometer.
These measurements provide accurate data for weather monitoring and forecasting, aiding planning and safety.
Question 3. Match Column A with the correct option in Column B.
|
Column A |
Column B |
|
1. Anemometer |
(a) Measures humidity |
|
2. Hygrometer |
(b) Measures rainfall |
|
3. Rain Gauge |
(c) Measures wind speed |
|
4. Barometer |
(d) Measures air pressure |
|
5. Thermometer |
(e) Measures temperature |
Answer
|
Column A |
Column B |
|
1. Anemometer |
(c) Measures wind speed |
|
2. Hygrometer |
(a) Measures humidity |
|
3. Rain Gauge |
(b) Measures rainfall |
|
4. Barometer |
(d) Measures air pressure |
|
5. Thermometer |
(e) Measures temperature |
Explanations:
- 1 → C: Anemometers measure wind speed with spinning cups.
- 2 → A: Hygrometers are used to check humidity levels in the air.
- 3 → B: Rain gauges collect and measure rainfall in millimeters.
- 4 → D: Barometers record atmospheric pressure to forecast storms.
- 5 → E: Thermometers are used for measuring air temperature.
Question 4. Explain the five main elements of weather and how they affect us.
Answer
Five main elements of weather and how they affect us are as follows:
- Temperature tells us how hot or cold the air is.
- Precipitation includes rain or snow.
- Atmospheric pressure influences storms and calm weather.
- Wind helps with pollination and affects rainfall and soil.
- Humidity determines how dry or sticky the air feels.
Question 5. Explain the role of weather stations and how Automated Weather Stations (AWS) enhance weather monitoring, with examples.
Answer
Weather stations help in measuring different weather elements at a specific location. They use instruments like:
- Thermometer – measures temperature
- Rain gauge – measures rainfall
- Barometer – measures air pressure
- Anemometer – measures wind speed
- Hygrometer – measures humidity
These stations take regular readings to help track weather patterns and forecast future conditions.
- Automated Weather Stations (AWS) are advanced systems that use sensors to collect data on temperature, humidity, wind, rainfall, and air pressure without human help. This makes the data more accurate and timely.
- For example, in 2023, an AWS was installed at a glacial lake in Sikkim at over 4800 meters height. It helps monitor weather changes and provides early warnings about possible risks.
- AWS are useful in many areas like agriculture, aviation, navigation, and environmental monitoring, as they improve safety and decision-making, especially in remote or difficult locations.
Question 6. How do wind instruments help us understand weather better?
Answer
Wind direction is shown using a wind vane, while speed is measured with an anemometer.
- Wind socks are used at airports to observe wind movement.
- These tools help in studying wind behaviour, which affects rainfall, seed dispersal, and flying conditions.
- Wind moves from high to low pressure areas.
- Measuring wind is important for pilots, sailors, and farmers.
Question 7. How is temperature measured, and what types of thermometers are used?
Answer
Temperature is measured using thermometers.
- Clinical thermometers are used for body temperature, while laboratory thermometers measure environmental temperatures.
- Digital thermometers are modern, accurate, and can store data.
- They can also record maximum and minimum temperatures.
- Temperature is recorded in Celsius or Fahrenheit.
- Understanding temperature patterns helps in weather forecasting and health safety.
Question 8. Describe how rainfall is measured using a rain gauge.
Answer
A rain gauge collects rain through a funnel into a cylinder.
- The depth of the water is then measured on a scale, usually in millimeters.
- If it snows, the snow is melted before measurement.
- This helps in calculating the total precipitation over a day or month.
- Accurate rainfall data is important for farming, water management, and flood control.
 |
| Rain Gauge |
Question 9. What is atmospheric pressure, and why is it important in weather studies?
Answer
Atmospheric pressure is the weight of air pressing down on Earth’s surface.
- It is measured using a barometer, typically in millibars.
- Low pressure can lead to storms and cyclones, while high pressure brings clear skies.
- Pressure also varies with height—lower at high altitudes and higher at sea level.
- Knowing pressure changes helps meteorologists predict weather conditions.
Question 10. Explain the five elements of weather and their significance in understanding weather patterns.
Answer
The five elements of weather are:
- Temperature: Measures how hot or cold the atmosphere is, affecting human comfort, agriculture, and energy use. It is measured using a thermometer in degrees Celsius or Fahrenheit.
- Precipitation: Includes rain, snow, sleet, or hail, indicating the amount of water falling from the sky. It impacts water supply and farming, measured by a rain gauge in millimetres.
- Atmospheric Pressure: The weight of air above the Earth's surface, measured by a barometer in millibars. It helps predict storms or cyclones, as low pressure often signals bad weather.
- Wind: The movement of air, characterized by speed and direction, measured by an anemometer and wind vane. It influences weather patterns, aviation, and farming.
- Humidity: The amount of water vapour in the air, measured by a hygrometer as relative humidity. It affects comfort, evaporation rates, and industrial processes like food processing.
These elements collectively define weather conditions at a place and time, and their data helps meteorologists forecast weather and prepare for extreme events.
Question 11. Why is understanding weather important for different professions and governments?
Answer
Understanding weather is important for different professions and governments is following way:
- Farmers need to know when to plant or protect crops.
- Pilots and sailors need wind and visibility updates for safety.
- Governments rely on forecasts to prepare for disasters like cyclones or floods.
- Accurate weather data helps plan relief operations and avoid loss.
- Weather understanding supports decision-making in agriculture, transport, and disaster management.
Question 12. What are the differences between dry and humid weather?
Answer
The differences between dry and humid weather are as follows:
|
Aspect |
Dry Weather |
Humid Weather |
|
Humidity Level |
Low (around 20-40%) |
High (around 60-80%) |
|
Sweat Evaporation |
Sweat evaporates quickly, making the body feel cooler |
Sweat evaporates slowly, making the body feel hotter and stickier |
|
Comfort level |
Generally more comfortable in warm temperatures |
Can feel uncomfortable even at moderate temperatures |
|
Clothes Dying |
Clothes dry quickly |
Clothes are slowly |
|
Typical Locations |
Inland or desert areas (Example: Jaipur) |
Coastal or tropical areas (Example: Kochi) |
|
Health impact |
May cause dry skin or dehydration |
May cause fatigue, overheating or fungal infections |
Question 13. How do weather stations function, and what instruments do they use?
Answer
Weather stations collect data on temperature, rainfall, wind, humidity, and air pressure.
- They use tools like thermometers, rain gauges, barometers, anemometers, and hygrometers.
- This information helps track and forecast weather.
- Automated Weather Stations (AWS) use sensors to record data without human effort.
- Weather stations are set up in cities, farms, and high-altitude areas for accuracy.
Question 14. Discuss the importance of weather forecasting and how it benefits society. (5 Marks)
Answer
Weather forecasting involves predicting future weather conditions using data collected from instruments like thermometers, barometers, and automated weather stations. Its importance lies in its ability to prepare society for various weather events, enhancing safety and efficiency. Key benefits include:
- Disaster Preparedness: Accurate forecasts warn of extreme weather like cyclones, floods, or heat waves, allowing governments to evacuate areas, mobilize resources, and reduce loss of life and property.
- Agriculture: Farmers rely on forecasts to plan sowing, irrigation, and harvesting, improving crop yields and food security.
- Aviation and Navigation: Pilots and sailors use wind and pressure data to ensure safe travel, avoiding turbulent weather.
- Daily Planning: Individuals use forecasts to choose appropriate clothing, plan outdoor activities, or prepare for temperature changes.
- Environmental Monitoring: Forecasting supports conservation efforts by predicting conditions that affect ecosystems, such as droughts or heavy rainfall.
By providing timely and accurate information, weather forecasting helps society adapt to changing conditions, making it an essential tool for modern life.