Chapter 4- Heat-Class 7 Question and Answer (Short)

Chapter 4 – Heat – Short Questions and Answers (Solved Worksheet)

Question- What are woollen clothes made from?

Answer- Woollen clothes are made from animal fibres.

Question- How is temperature usually measured?

Answer- Temperature is usually measured using a thermometer.

Question- What scale is commonly used to express temperature?

Answer- The Celsius scale is commonly used to express temperature.

Question- What is crucial to observe before reading a thermometer?

Answer- Understanding the scale and observing the bigger marks and divisions is crucial before reading a thermometer.

Question- What precaution should be taken before using a thermometer?

Answer- Before using a thermometer, it should be properly cleaned, preferably with an antiseptic solution.

Question- Why are digital thermometers considered safer?

Answer- Digital thermometers are considered safer because they do not contain toxic mercury.

Question- How should a clinical thermometer be cleaned?

Answer- A clinical thermometer should be cleaned using an antiseptic solution to ensure hygiene.

Question- What should be the position of the mercury level before using a clinical thermometer?

Answer- Before using a clinical thermometer, the mercury level inside it should be below 35°C.

Question- What is the purpose of a laboratory thermometer?

Answer- A laboratory thermometer is used to measure the temperature of objects other than the human body.

Question- What is conduction?

Answer- Conduction is the process by which heat moves from the hotter end to the colder end of an object, commonly observed in solids.

Question- Why do cooking pans typically have plastic or wood handles?

Answer- Cooking pans have plastic or wood handles because these materials are poor conductors of heat, preventing burns when holding the hot pan.

Question- How does heat generally transfer in solids?

Answer- In solids, heat generally transfers through conduction.

Question- What materials are considered good conductors of heat?

Answer- Aluminium, iron, and copper.

Question- Which materials are typically poor conductors or insulators of heat?

Answer- Plastic and wood.

Question- How does touching the non-dipped end of the materials help in classifying them as conductors or insulators?

Answer- If the non-dipped end feels hot, the material is a conductor, and if it doesn’t feel hot, the material is an insulator.

Question- What happens to hot water in the convection experiment?

Answer- The hot water rises upwards because it becomes less dense when heated.

Question- Why does the hand above the flame feel hotter than the hand on the side of the flame in the air convection experiment?

Answer- Because hot air rises, leading to an upward flow of hot air above the flame, making it feel hotter.

Question- What creates a sea breeze during the day in coastal areas?

Answer- Hot air rises over the land, and cooler air from the sea rushes in to replace it, creating a sea breeze.

Question- What causes the hot water to rise in the convection experiment?

Answer- Hot water rises because it becomes less dense when heated.

Question- What is the main method of heat transfer in water and air?

Answer- Convection is the main method of heat transfer in water and air.

Question- During the day in coastal areas, what type of breeze is experienced?

Answer- A sea breeze is experienced during the day in coastal areas.

Question- What causes the land to heat up faster than the sea during the day?

Answer- The land heats up faster than the sea because soil and rocks can absorb and retain heat more effectively than water.

Question- What is the cooler air that rushes in from the sea during the day called?

Answer- The cooler air that rushes in from the sea during the day is called the sea breeze.

Question- Which type of breeze, sea breeze or land breeze, is experienced during the night?

Answer- The land breeze is experienced during the night.

Question- How does heat from the sun reach us through space?

Answer- Heat from the sun reaches us through space by the process of radiation, which doesn’t require any medium.

Question- What happens to an object’s temperature when it absorbs heat through radiation?

Answer- When an object absorbs heat through radiation, its temperature increases.

Question- Why are you advised to use an umbrella in the sun?

Answer- An umbrella is advised to be used in the sun because it acts as a shield against direct sunlight, reducing the amount of heat radiation that reaches your body and keeping you cooler.

Question- What is one effective method to create trapped layers of air in the walls of buildings?

Answer- One effective method to create trapped layers of air in the walls of buildings is by using hollow bricks in construction.

Question- How does the trapped air in hollow bricks affect heat transfer?

Answer- The trapped air in hollow bricks acts as a barrier against the transfer of heat, resisting the entry of external heat into the building during hot weather and preventing the escape of warmth during cold weather.

Question- What are the benefits of using hollow bricks in construction?

Answer- The benefits include energy efficiency, a comfortable living environment, reduced environmental impact, and cost-effectiveness in terms of long-term energy savings.

Question- Why are light-coloured clothes preferred during summer?

Answer- Light-coloured clothes are preferred during summer because they reflect most of the sunlight, absorbing less heat, which helps in staying cooler.

Question- What observation is made when two identical tin cans, one painted black and the other white, are placed in the sun?

Answer- The water in the black-painted can is usually warmer because dark colours absorb more sunlight and convert it into heat energy.

Question- Why are dark-coloured clothes chosen in winter?

Answer- Dark-coloured clothes are chosen in winter because they absorb more sunlight and retain heat better, helping to stay warm.

Question- What makes wool an excellent insulator in winter clothing?

Answer- Wool acts as an excellent insulator because it traps tiny air pockets within its fibres, preventing body heat from escaping and keeping the cold out.

Question- Why is it often better to use two thin blankets joined together in winter instead of one thick blanket?

Answer- Using two thin blankets creates an additional layer of trapped air between them, acting as an insulator and preventing body heat from escaping, making one feel warmer.

Question- How does trapped air within the wool fibres help in keeping warm?

Answer- Trapped air is a poor conductor of heat; it creates a barrier within the wool fibres, preventing body heat from escaping into the cold surroundings.

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