Heat Transfer in Nature Class 7 Extra Questions and Answers Science Chapter 7

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Class 7 Science Chapter 7 Heat Transfer in Nature Extra Questions

Class 7 Science Chapter 7 Extra Questions on Heat Transfer in Nature

Heat Transfer in Nature Class 7 Very Short Question Answer

Question 1.
What is the main source of heat and light for the Earth?
Answer:
The Sun.

Question 2.
Give one example of a good conductor of heat.
Answer:
Copper.

Question 3.
Name the process by which heat travels through solids.
Answer:
Conduction.

Question 4.
During the day, wind blows from to at the seaside.
Answer:
Sea to land.

Question 5.
What is the process called when water seeps into the ground?
Answer:
Infiltration.

Question 6.
Name the three processes by which heat is transferred.
Answer:
Conduction, convection, and radiation.

Question 7.
Does heat transfer occur easily through wood?
Answer:
No. Wood is a poor conductor of heat.

Question 8.
Give an example of a fluid.
Answer:
Water.

Question 9.
Does warm air rise or sink?
Answer:
Rise.

Question 10.
Is air a good or poor conductor of heat?
Answer:
Air is a poor conductor of heat.

Heat Transfer in Nature Class 7 Short Question Answer

Question 1.
Why are cooking utensils generally made of metals?
Answer:
Cooking utensils are generally made of metals because metals are good conductors of heat.

Question 2.
Why does water seep faster through gravel than clay?
Answer:
The spaces between gravel particles are wider compared to those in sand and clay.

Question 3.
What has led to the depletion of groundwater?
Answer:
Excessive groundwater extraction, decreased vegetation cover, and increased concrete surfaces have led to the depletion of groundwater.

Question 4.
What happens to water vapour as it rises up in the atmosphere?
Answer:
As water vapour rises, it cools down and condenses to form clouds.

Question 5.
Why do we prefer light- coloured clothes in summer?
Answer:
Light-coloured clothes reflect most of the heat that falls on them, so we feel more comfortable wearing them during summers.

Question 6.
Explain land breeze.
Answer:
Land breeze is the movement of cooler air from the land towards the sea at night, when the land cools down faster than the water.

Question 7.
Describe the movement of water when a beaker is heated from below.
Answer:
The water at the bottom gets heated, expands, becomes lighter, and rises, while cooler water from the sides comes down.

Heat Transfer in Nature Class 7 Long Question Answer

Question 1.
Describe the modem method of water conservation used in Ladakh.
Answer:
In Ladakh, people develop a new way to conserve water using ice stupas. During winter, water from mountain streams is channelled through underground pipes and sprayed into the cold air, where it freezes and builds up into a cone-shaped structure. These ice stupas then melt slowly during spring, providing water for farming and other needs throughout the summer.

Question 2.
Discuss the ways in which the water cycle is beneficial.
Answer:
The water cycle is important for several reasons:

• It helps in redistributing water in various areas on the Earth and replenishing water in rivers, lakes, and oceans.
• It helps to conserve the total amount of water on the Earth.
• It ensures that groundwater sources are recharged, helping to maintain a sustainable ground-water supply.

Question 3.
Explain how the properties of heat transfer are utilized in designing houses for extreme climates.
Answer:
In places with extreme climates, the principles of heat transfer are used to design houses that remain cool or warm.
In cold regions, houses may be built with materials that are poor conductors of heat, like wood and mud, to prevent heat loss and keep the house warm. In hot regions, houses may be built with hollow bricks, which trap air (a poor conductor of heat) to keep the house cool.

Question 4.
Explain how water gets heated by convection in a beaker.
Answer:
When heating a beaker of water:

• Water at the bottom gets heated, becomes lighter, and rises.
• Cooler water from above moves down along sides of the beaker to replace it.
• This cycle continues until all the water is heated.

This heat transfer by the movement of water is called convection.

Question 5.
Compare the three methods of heat transfer: conduction, convection, and radiation. Provide examples of each from everyday life.
Answer:

Method	How Heat is Transferred	Medium Needed	Example
Conduction	By direct contact; heat passes from one particle to another.	Yes (solids)	Metal spoon getting hot in a hot soup.
Convection	By movement of particles in liquids or gases.	Yes (Liquids/gases)	Boiling water, sea breeze.
Radiation	Directly, without any medium.	No	Sun warming the Earth, heat from fire.

Question 6.
A metal spoon is used to stir a hot cup of soup. After a while, the spoon’s handle also becomes hot. (NCERT Examplar)
(a) Name the process by which heat is transferred through the spoon.
(b) Explain why the handle becomes hot.
(c) If the spoon was made of wood instead of metal, would the handle become hot? Explain why or why not.
Answer:
(a) The process by which heat is transferred through the spoon is conduction.
(b) The handle becomes hot because metals are good conductors of heat. Heat is transferred from the hotter end (in the soup) to the colder end (the handle) along the spoon.
(c) If the spoon was made of wood, the handle would not become as hot. Wood is a poor conductor (or insulator) of heat, which means it does not allow heat to pass through it easily.

Question 7.
Coastal areas experience sea breezes during the day and land breezes at night. (NCERT Exemplar) . ‘
(a) Explain what causes a sea breeze.
(b) Explain what causes a land breeze.
(c) Why do people in coastal regions often have windows in their houses facing the sea?
Answer:
(a) During the day, the land heats up faster than the water, causing the warm air above the land to rise. This causes cooler air to move from the sea towards the land, creating a sea breeze.
(b) At night, the land cools down faster than the water. The air above the sea is warmer and rises up. Cooler air from the land then moves towards the sea, creating a land breeze.
(c) People in coastal regions often have windows facing the sea to allow the cool sea breeze to enter their homes during the hot day, providing a natural way to cool the living spaces.

Question 8.
You have two blankets: one thick and one made of two thin layers,
(a) Which blanket would keep you warmer in a cold night?
(b) Explain the reason for your answer using the concept of heat transfer. (NCERT Exemplar)
Answer:
(a) The blanket made of two thin layers would keep us warmer.
(b) The air trapped between the two thin layers of the blanket acts as a poor conductor (or insulator) of heat. This trapped air reduces the heat flow from our body to the cold surroundings, thus keeping us warmer than a single thick blanket.

Heat Transfer in Nature Class 7 Case Based Questions

I. Pema notices that her grandmother uses metal pots for cooking but drinks tea from a clay cup. She wonders why different materials are used.

Question 1.
Why are metals used for cooking utensils but clay used for cups?
Answer:
Metals are good conductors of heat; they quickly transfer heat to the food for faster cooking. Clay is a poor conductor of heat, so it keeps tea hot for a longer time and prevents the cup from becoming too hot to hold.

II. During his visit to Kerala, Palden observed that during the day, cool winds came from the sea towards the land.

Question 1.
What is this phenomenon called and why does it happen?
Answer:
This phenomenon is’called a sea breeze. It happens because land heats up faster than sea water during the day. The warm air above the land rises, and cooler air from the sea moves in to replace it.

Heat Transfer in Nature Extra Questions for Practice

Very short Answer Type Questions

Question 1.
Give one example of a poor conductor of heat.

Question 2.
What kind of materials are cooking utensils usually made of?

Question 3.
Does a land breeze occur during the day or at night?

Question 4.
What is the continuous cyclic movement of water on Earth called?

Question 5.
What is the process by which water changes from a liquid to a gas?

Short Answer Type Questions

Question 1.
Explain sea breeze.

Question 2.
Why do we prefer two thin blankets over one thick blanket in winter?

Question 3.
What is radiation?

Question 4.
What are poor conductors of heat? Give two examples.

Long Answer Type Questions

Question 1.
With reference to a water cycle in nature, explain the following terms:
(a) Evaporation
(b) Transpiration
(c) Condensation
(d) Precipitation
(e) Infiltration.

Question 2.
Design an activity to show how can we observe conduction, convection, and radiation happening together?

Case-Based Questions

I. In the Himalayan region, houses are built using two wooden layers filled with mud and cow dung between them. Answer the following question:
I. Why are such materials used in house construction in cold regions?
II. During winter vacation, Palden travelled from Gangtok, where it was very cold, to Kerala, where he found the weather to be warm and humid. This made him and Pema curious about why different places have different temperatures. When discussing clothing choices, they observed that in Gangtok, they wear woollen clothes, while in Kerala, people likely wear lighter cotton clothes.

Answer the following questions:

Question 1.
Why the weather conditions of different areas differ?

Question 2.
In most part of North India, people wear woolen clothes in winters and light cotton clothes in summers. Explain, why?

Multiple Choice Questions (MCQs)

Question 1.
Sea breeze happens because:
(a) Water heats up faster than land.
(b) Land heats up faster than water.
(c) Water cools faster than land.
(d) Land and water heat equally.

Question 2.
Which mode of heat transfer does not require a medium?
(a) Conduction
(b) Convection
(c) Radiation
(d) Absorption

Question 3.
During night at coastal areas, the wind blows from:
(a) Sea to land
(b) Land to sea
(c) Land to sky
(d) Sea to sky

Question 4.
Which colour clothes should we wear in summer to stay cool?
(a) Dark-coloured
(b) White or light-coloured
(c) Multi-coloured
(d) Shiny metallic

Question 5.
What is the process called when water seeps into the ground?
(a) Convection
(b) Condensation
(c) Infiltration
(d) Radiation

Assertion-Reason Questions

Directions: Each of the questions 1 and 2 contain two statements – first ‘Assertion’ and second ‘Reason’. Select the correct answer to these questions from the codes (a), (b), (c) or (d) as given below:
(a) Both Assertion and Reason are true and Reason is the correct explanation of Assertion.
(b) Both Assertion and Reason are true and Reason is NOT the correct explanation of Assertion.
(c) Assertion is true and Reason is false.
(d) Assertion is false and Reason is true.

(i) Assertion (A): During the day, a land breeze blows from the sea to the land.
Reason (R): The land gets heated faster than water during the day.

(ii) Assertion (A): Woollen clothes keep us warm in winter.
Reason (R): Wool traps air, and air is a poor conductor of heat.

Fill in the blanks

(a) The movement of cooler air from land to sea during the night is called ________ breeze.
(b) The continuous movement of water through evaporation, condensation, and precipitation is called the ________ cycle.
(c) The seepage of water through soil and rocks into the ground is called ________
(d) Underground layers that store water are known as ________
(e) The traditional room heater used in the Himalayan region is called ________

True or False

State whether True or False and answer with reason:
(i) Infiltration refers to water % seeping into the ground.
(ii) Radiation requires a medium for heat transfer.
(iii) Glass is a good conductor of heat.
(iv) Metals are poor conductors of heat.
(v) In conduction, the particles of the material move from one place to another.

Match the following

Question 1.

Column A	Column B
(i) Poor conductor of heat	(a) Radiation
(ii) Good conductor of heat	(b) Convection
(iii) Heat from fire to us	(c) Wood
(iv) Air movement in heated water	(d) Aluminum