Class 7 new ncert Chapter 2 SST Solution - Understanding Weather

Chapter 02: Understanding Weather

Question 1: What is weather?

Answer: The atmospheric condition of a place at a particular time (such as temperature, rainfall, wind, etc.) is called weather.

Question 2: What are the main elements of weather?

Answer: The main elements of weather are:

1. Temperature
2. Precipitation (rain, snow, etc.)
3. Atmospheric pressure
4. Wind
5. Humidity

Question 3: What is temperature? How is it measured?

Answer: Temperature tells how hot or cold the air is. It is measured using a thermometer.

Question 4: What is the atmosphere?

Answer: The layer of gases surrounding the Earth is called the atmosphere.

Question 5: What is the troposphere?

Answer: The lowest layer of the atmosphere is called the troposphere. All weather-related activities occur here.

Question 6: What is precipitation? How is it measured?

Answer: Water that falls from the sky (such as rain, snow, hail) is called precipitation. Rainfall is measured using a rain gauge.

Question 7: What is atmospheric pressure? How is it measured?

Answer: The pressure exerted by air on the Earth’s surface is called atmospheric pressure. It is measured using a barometer.

Question 8: What is wind? How are its direction and speed measured?

Answer: Air moving from a high-pressure area to a low-pressure area is called wind.

• Wind direction → measured by a wind vane.
• Wind speed → measured by an anemometer.

Question 9: What is humidity? How is it measured?

Answer: The amount of water vapor present in the air is called humidity. It is measured using a hygrometer.

Question 10: What is meteorology?

Answer: The study of weather and its changes is called meteorology.

Question 11: What is a weather station?

Answer: A place where all weather instruments are installed and data is collected is called a weather station.

Question 12: What is an automatic weather station?

Answer: A station that automatically measures and records weather data.

Question 13: What is weather forecasting? Why is it important?

Answer: Predicting future weather conditions is called weather forecasting. It is important because:

• It helps in disaster management.
• It supports farmers.
• It helps in planning travel.
• It is important for fishermen and pilots.

Question 14: How was weather predicted using traditional methods?

Answer: People observed natural signs such as:

• Ants carrying eggs
• Birds flying low
• Frogs croaking

Question 15: Why is air pressure low at high altitudes?

Answer: At higher altitudes, the air is thinner, so the pressure is lower.

Question 16: Why do clothes dry slowly in high humidity?

Answer: Because the air already contains a lot of moisture, water does not evaporate quickly.

Question 17: What are the benefits of accurate weather prediction?

Answer: The benefits of accurate weather prediction are:

• Timely preparation
• Help in agriculture
• Disaster prevention
• Easy travel planning

NCERT Solution

Question 1. Match the elements of weather with the instruments used to measure them.

Answer: The correct matching is as follows:

• Hygrometer → (घ) Humidity
• Anemometer → (ग) Wind direction and speed
• Barometer → (ख) Atmospheric pressure
• Thermometer → (ङ) Temperature
• Rain Gauge → (क) Precipitation

Question 2: Jyotsna is planning what clothes to carry for her school trip to Mumbai in June. She checks the weather forecast, which shows 29°C temperature and 84% humidity. What advice would you give her?

Answer: In Mumbai during June, the weather is hot and very humid. Therefore, Jyotsna should carry:

• Light and loose cotton clothes
• Sweat-absorbing clothes
• Umbrella or raincoat (as rain may start)
• Comfortable slippers or shoes
• Extra clothes (due to humidity and sweat)

These clothes will keep her comfortable in heat and humidity and also protect her from rain.

Question 3: Imagine that your group is setting up a rain gauge. Here are some possible locations:

• School vegetable garden
• School building rooftop
• Open field with a raised platform
• School boundary wall
• School laboratory veranda

Answer: The most suitable location is: Open field with a raised platform

Reasons:

• It is an open area where rain can fall directly
• No nearby obstacles (trees, walls), so measurement will be accurate
• Wind or obstruction will not affect water collection

Let’s Explore:

Question 1: How can we observe and assess the weather around us?

Answer: We can assess the weather around us in the following ways:

• By feeling the temperature (hot or cold)
• By observing the sky (clouds, sunlight, fog)
• By sensing wind speed and direction
• By observing whether it is raining or not
• By getting information from news, mobile apps, or TV

In this way, we can understand weather through daily experiences and instruments.

Question 2: How do weather forecasts help us prepare for events like heavy rainfall, storms, droughts, and heat waves?

Answer: Weather forecasts give us advance warnings, allowing us to prepare:

• Heavy rainfall: People can move to safer places
• Storms: Fishermen avoid going to sea
• Drought: Farmers manage water in advance
• Heat wave: People avoid going outside and drink more water

Thus, forecasts help reduce loss of life and property.