NCERT Solutions for Class 7 social science Chapter 2: Understanding the Weather Class 7

Make a rain gauge as shown in the below diagram. Place the rain gauge in an open area, away from objects that might obstruct rain. Ensure that the rain gauge is on a flat surface and will not tilt or topple with the wind. Using the measuring scale, record the amount of rainwater collected at the same time every day, for a month. (If there is snow, allow it to melt before taking the measurement.) Calculate the average rainfall for every week in that month and comment on the variation from week to week. (Page 34)

Answer:
Do it yourself.

Where do you think the humidity is likely to be more, Kochi or Jaipur? You might guess that Kochi has higher humidity than Jaipur because it is located near the sea. But how will we know for sure? If we had to compare the humidity level between Kochi and Mangaluru, how would we do it? Discuss with your classmates. (Page 37)
Answer:
Do it yourself

Discuss in pairs, different situations in which weather predictions are useful. Make a list and after you have completed your list, share it and discuss it with the pair sitting next to you. How many different categories of situations have you been able to identify? (Page 41)
Answer:
Do it yourself.

Look carefully at the below map. (Page 40-41)

(i) What do you observe happening on that day (19 May 2024)? What are the various weather conditions that the IMD is alerting people to?
Answer:
On 19 May 2024, the IMD issued alerts for:

Let us imagine Krishnan from Chennai is speaking with Amir in Kashmiri. Krishnan tells Amir that it has become chilly in Chennai after it rained the previous night. Amir asks him how cold it is. How will Krishnan explain to Amir how cold it is? After all, what is cold for Krishnan may not be cold for Amir?
Answer:
Krishnan, who lives in Chennai, tells Amir from Kashmir that it has become chilly after it rained the previous night. When Amir asks how cold it is, Krishnan explains that the temperature has dropped to around 22°C, which feels quite cold for people in Chennai. He says that they are used to hot and humid weather most of the year, so even a small drop in temperature feels chilly. He might even mention that he had to wear a light sweater in the morning. Amir, coming from Kashmir where winter temperatures can go below 0°C, finds this surprising. For him, 22°C is quite pleasant and not cold at all. This shows that what feels cold or warm can be different depending on the climate people are used to.

Why do you think it would be important to measure the atmospheric pressure? Who are the people most likely to use such measurements? (Page 35)
Answer:
It is important to measure the atmospheric pressure:

People who journey to places at a high altitude are advised to make pause on the way to allow the body to acclimatise. Our army personnel serve in high- altitude places like Khardungla in Ladakh, which is over 5600 metres above sea level. It is hard to image how they live and work in places where the oxygen level is so low – the atmospheric pressure there is generally about 650 millibars! (Page 35)
Answer:
The army personnel live in:

Have you seen seeds like these flying in the wind (see the below image)? What would happen to the seeds if there was no wind? (Page 36)

Answer:
If there was no wind, the seeds would not be able to spread far from the parent plant. Most wind- dispersed seeds would fall right below the plant that produced them. This would cause the plants to grow very close to each other, leading to competition for sunlight, water, and nutrients. Some seeds might not grow at all because there would not be enough space or resources. Without wind, seeds would not reach new places to grow, and this would reduce the number of new plants in different areas. Over time, some types of plants might even disappear because they cannot spread their seeds properly.

If the humidity in Delhi is at 52% while in Kochi it is 84% in which of the two places are wet clothes likely to dry faster? And where are you likely to sweat more, assuming the temperature in the same in both places? (Page 38)
Answer:
If the humidity in Delhi is 52% and in Kochi it is 84%, here’s what would happen:

Match the instrument with the weather element it measures.

Hygrometer

Jyotsna is deciding what clothes to pack for her school trip to Mumbai in June. She looks at the weather forecast, which predicts 29°C and 84% humidity. What would be your advice to her?

Imagine that a small group of students is setting up a rain gauge. Here are some options for the site.
(i) The school vegetable garden.
(ii) The terrace of the school building.
(iii) Open ground with elevated platform.
(iv) Compound wall of school.
(v) Verandah of the school laboratory.
Discuss in your group and finalise the site. Write down the reasons for your decisions.
Answer:
Do it yourself.

Below is a chart taken from IMD, Jammu and Kashmir. Looking at the data available, write a short script to report the weather conditions in different parts of Jammu and Kashmir on the data shown. (Hint: Cover the temperature range, maximum and minimum temperatures, humiditys, precipitation, etc.)