Extra Questions for Class 7 Science Chapter 4 Heat with Answer

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Heat Class 7 Extra Questions Science Chapter 4

The fourth chapter in the Class 7 Science curriculum, named “Heat,” plays a vital role in introducing learners to the notion of heat, its origins, and its impacts on various materials. This chapter, in alignment with the CBSE and NCERT syllabus, encompasses topics such as heat transmission, conductors and insulators, and temperature measurement. The additional questions for this chapter aim to deepen students’ grasp of these concepts and to improve their analytical and problem-solving abilities. These questions are essential for exam preparation and help solidify the understanding acquired from the textbook. By working on these extra questions, students can achieve a thorough comprehension of heat and its characteristics, which is crucial for their overall science education.

Long and Short Answer Type Extra Questions for Class 7 Science Chapter 4 Heat

Here are the short and long type extra questions for class 7 science chapter 4 Heat:

Short Answer Types Questions with Answer for Class 7 Science Chapter 4 Heat

Question: 1 What is conduction?

Answer: Conduction is the transfer of heat through a material without the movement of the material itself. It occurs when heat energy is passed from one particle to another through direct contact.

Question: 2 What is convection?

Answer: Convection is the transfer of heat in fluids (liquids or gases) where warmer, less dense regions rise and cooler, denser regions sink, creating a circulation of heat.

Question: 3 What are conductors?

Answer: Conductors are materials that allow heat to pass through them easily. Examples include metals like copper and aluminum.

Question: 4 What are insulators?

Answer: Insulators are materials that do not allow heat to pass through them easily. Examples include wood, plastic, and rubber.

Question: 5 How does heat transfer in solids?

Answer: In solids, heat transfer primarily occurs through conduction, where heat energy is passed from one particle to another through direct contact.

Question: 6 Do all hot bodies radiate heat?

Answer: Yes, all hot bodies radiate heat in the form of infrared radiation, which is a type of electromagnetic wave.

Question: 7 In which direction does the smoke go?

Answer: Smoke tends to rise upwards because it is warmer and less dense than the surrounding air, which is an example of convection.

Question: 8 What do you mean by temperature?

Answer: Temperature is a measure of the average kinetic energy of the particles in a substance. It indicates how hot or cold a substance is.

Question: 9 Which device is used to measure temperature?

Answer: A thermometer is used to measure temperature.

Question: 10 What is that silver stuff in a thermometer?

Answer: The silver stuff in a traditional thermometer is mercury, which expands and contracts with changes in temperature.

Question: 11 What is the unit of temperature as adopted by India?

Answer: In India, the Celsius scale (°C) is commonly used as the unit of temperature.

Question: 12 What is the normal temperature of a human being?

Answer: The normal body temperature of a human being is around 37°C (98.6°F).

Question: 13 What is the range of a laboratory thermometer?

Answer: The range of a laboratory thermometer typically varies, but it is usually between -10°C to 110°C.

Question: 14 What are conductors of heat?

Answer: Conductors of heat are materials that allow heat to pass through them easily, such as metals like copper and aluminum.

Question: 15 What is a clinical thermometer?

Answer: A clinical thermometer is a device used to measure the body temperature of humans or animals, usually with a range from 35°C to 42°C.

Question: 16 How does the heat travel in air?

Answer: In air, heat travels primarily through convection, where warmer air rises and cooler air sinks, creating a circulation of heat.

Question: 17 What do you understand by heat?

Answer: Heat is a form of energy that is transferred between objects or systems due to a temperature difference. It is associated with the motion of particles in a substance and can cause changes in temperature, state, or volume.

Question: 18 How do insulators work?

Answer: Insulators work by restricting the flow of heat. They have tightly packed particles that do not allow heat to pass through easily, thereby reducing heat transfer.

Question: 19 What is thermal conductivity?

Answer: Thermal conductivity is a measure of a material’s ability to conduct heat, indicating how quickly heat can be transferred through the material.

Question: 20 Why does the level of mercury rise in a thermometer when in contact with a hot object?
Answer: The mercury expands when heated, causing its level to rise in the thermometer.

Question: 21 Why do shopkeepers cover ice blocks with jute sacks?

Answer: Jute sacks act as insulators, slowing down the melting of ice blocks.

Question: 22 Why are radiators in cars painted black?

Answer: Black surfaces absorb more heat, improving the efficiency of heat transfer in radiators.

Question: 23 Can Paheli use the same method to keep a glass of cold drink cool?

Answer: Yes, wrapping in woolen clothes can insulate the cold drink, keeping it cool.

Question: 24 Which thermometer will show a greater rise in temperature, A or B?

Answer: Thermometer B will show a greater rise as heat rises, and it is directly above the flame.

Question: 25 In which direction should windows face in a coastal area

Answer: Windows should face the sea breeze for natural cooling.

Question: 26 Why doesn’t mercury fall or rise in a clinical thermometer when taken out of the mouth?

Answer: The kink in the thermometer prevents the mercury from falling back immediately.

Question: 27 Name the mode of heat transfer where no medium is required.

Answer: Radiation.

Question: 28 Why does a pan cool down when removed from the fire

Answer: Heat is transferred from the pan to the cooler surrounding air.

Question: 29 Why is it preferred to use two thin blankets rather than one thick blanket?

Answer: Air trapped between the blankets acts as an insulator, providing better warmth.

Question: 30 Why should we not hold the thermometer by its bulb while reading it?

Answer: Holding the bulb can transfer body heat to the thermometer, affecting the reading.

Question: 31 What is one application of the kink in a clinical thermometer?

Answer: The kink prevents mercury from falling back, maintaining the reading.

Question: 32 How do we find out how hot an object really is?

Answer: By measuring its temperature with a thermometer.

Question: 33 Is the body temperature of every person 37°C?

Answer: No, it can vary slightly around 37°C.

Question: 34 How can we measure the temperature of objects other than the human body?

Answer: Using a suitable thermometer designed for that object or substance.

Question: 35 How does heat travel in air?

Answer: Heat travels in air primarily through convection.

Question: 36Why are we advised to use an umbrella in the sun?

Answer: The umbrella provides shade and reflects sunlight, keeping us cooler.

Question: 37 Why are sharp jerks given to a clinical thermometer before using it

Answer: To bring the mercury level down to below 35°C for accurate reading.

Question: 38 Why is the handle of a pressure cooker covered with thick plastic?

Answer: The handle is covered with thick plastic because plastic is a poor conductor of heat, which prevents heat transfer and keeps the handle cool, making it safe to hold.

Question: 39 How do conduction and convection differ in the transfer of heat?

Answer: Conduction is the transfer of heat through a solid material without the movement of the material itself, while convection is the transfer of heat in fluids (liquids or gases) where warmer, less dense regions rise and cooler, denser regions sink, creating a circulation of heat.

Question: 40 What precautions should be taken while reading a clinical thermometer?

Answer: Ensure the thermometer is clean, shake it down to below 35°C before use, place it under the tongue and close the mouth, wait for 1-2 minutes, and read it at eye level without touching the bulb.

Question: 41 What is a limitation of a clinical thermometer?

Answer: A clinical thermometer has a limited temperature range, typically 35°C to 42°C, and cannot measure temperatures outside this range.

Question: 42 Why do we wear dark-colored clothes in winter and light-colored clothes in summer?

Answer: Dark-colored clothes absorb more heat, keeping us warmer in winter, while light-colored clothes reflect heat, keeping us cooler in summer.

Question: 43 Why are shiny reflectors used in room heaters?

Answer: Shiny reflectors are used in room heaters to reflect infrared radiation, directing more heat into the room and improving the heater’s efficiency.

Question: 44 Why is mercury used in thermometers instead of water?

Answer: Mercury is used in thermometers because it has a high coefficient of expansion, is visible, does not stick to glass, and has a wide range of temperatures it can measure.

Question: 45 Why are air conditioners fitted at a higher level on the wall of a room?

Answer: Air conditioners are fitted at a higher level to allow cool air to sink and spread evenly throughout the room, as cool air is denser than warm air.

Question: 46 How do kites and eagles fly without flapping their wings?

Answer: Kites and eagles fly without flapping their wings by gliding on thermal currents or updrafts, which provide the lift needed to stay aloft with minimal effort.

Question: 47 What are maximum and minimum thermometers used for?

Answer: Maximum and minimum thermometers are used to record the highest and lowest temperatures reached over a period, typically using mercury and alcohol, respectively.

Long Answer Types Questions with Answer for Class 7 Science Chapter 4 Heat

Question: 1 What are the differences between heat and temperature?

Answer: Heat is a form of energy that flows between two objects due to a temperature difference, while temperature is a measure of the average kinetic energy of the particles in a substance. Heat is transferred from a hotter object to a cooler one, whereas temperature is a property that indicates how hot or cold an object is.

Question: 2 Why does water heat more quickly when heated from the bottom rather than the top?

Answer: When heat is applied at the bottom of a water vessel, the water at the bottom becomes less dense due to heating and rises, while the cooler, denser water at the top sinks. This creates a convection current, which helps in the uniform and quicker heating of water. If heated from the top, convection currents are not formed, and heat transfer is slower.

Question: 3 How can you prove that heat radiation can travel through a vacuum?

Answer: An experiment to demonstrate that heat radiation can travel through a vacuum is the Herschel’s experiment. Place a thermometer in the shade and another in the sunlight, both inside vacuum flasks to minimize heat loss by conduction or convection. The thermometer in the sunlight will show a higher temperature, proving that heat radiation (infrared radiation from the sun) can travel through a vacuum and increase the temperature.

Question: 4 What causes oceanic currents, and how do they occur?

Answer: Oceanic currents are large-scale movements of water in the ocean, driven by factors such as wind, differences in water density, and the Earth’s rotation. Wind-driven currents occur near the ocean surface and are influenced by prevailing winds and the Coriolis effect. Density-driven currents, also known as thermohaline circulation, occur at greater depths and are caused by variations in water temperature and salinity. These currents play a crucial role in regulating the Earth’s climate by redistributing heat and nutrients around the globe. They can affect weather patterns, marine ecosystems, and human activities such as shipping and fishing.

Question: 5 For setting curd, a small amount of curd is added to warm milk. The microbes present in the curd help in setting if the temperature of the mixture remains approximately between 35°C to 40°C. At places where room temperature remains much below the range, setting of curd becomes difficult. Suggest a way to set curd in such a situation.

Answer: In colder environments, you can set curd by keeping the mixture in a warm place, such as near a heater or in a warm oven (turned off) to maintain the temperature. You can also use an insulated container to retain warmth or wrap the container with a thick cloth or blanket to keep it warm.

Question: 6 The freezer is located at the top of the refrigerator. Explain why.

Answer: The freezer is located at the top of the refrigerator because cold air is denser and sinks, allowing the cooler air from the freezer to circulate down and help cool the refrigerator section below, making the cooling process more efficient.

Question: 7 At a campsite, there are tents of two shades. One made with black fabric and the other with white fabric. Which one will you prefer for resting on a hot summer afternoon? Give a reason for your choice. Would you like to prefer the same tent during winter?

Answer: On a hot summer afternoon, the white tent is preferable because it reflects sunlight and heat, keeping the inside cooler. In winter, the black tent would be preferable as it absorbs more heat, keeping the inside warmer.

Question: 8 Explain the reason for serving tea in China clay cups and plates.

Answer: Tea is served in China clay cups and plates because China clay (porcelain) has low thermal conductivity, keeping the tea warm for a longer period. Additionally, it is non-porous, preventing the absorption of flavors and smells, ensuring the tea’s taste remains unaltered.

Extra Multiple Choice Questions (MCQs) for Class 7 Science Chapter 4 Heat

Question: A marble tile would feel cold as compared to a wooden tile on a winter morning because the marble tile

(a) is a better conductor of heat than the wooden tile

(b) is polished while wooden tile is not polished

(d) is a poor conductor of heat than the wooden tile

Answer: (a) is a better conductor of heat than the wooden tile

Question: A beggar wrapped himself with a few layers of newspaper on a cold winter night. This helped him to keep himself warm because.

(a) friction between the layers of newspaper produces heat

(b) air trapped between the layers of newspaper is a bad conductor of heat

(d) newspaper is at a higher temperature than the temperature of the surroundings

Answer: (b) air trapped between the layers of newspaper is a bad conductor of heat

Question: Heat always flows

(a) from a colder object to a hotter object

(b) from a hotter object to a colder object

(d) None of the above

Answer: (b) from a hotter object to a colder object

Question: Paheli and Boojho measured their body temperature. Paheli found her to be 98.6°F and Boojho recorded 37°C. Which of the following statements is true?

(a) Paheli has a higher body temperature than Boojho.

(b) Paheli has a lower body temperature than Boojho.

(d) Both are suffering from fever.

Answer: (c) Both have normal body temperature.

Question: Which of the following is a good conductor of heat?

(a) Wood

(b) Plastic

(d) Glass

Answer: (c) Aluminum

Question: In which of the following methods of heat transfer do the particles of the medium not move?

(a) Conduction

(b) Convection

(d) Both convection and radiation

Answer: (a) Conduction

Question: Woolen clothes keep us warm in winter because they

(a) absorb heat from the surroundings

(b) do not radiate heat

(d) are good conductors of heat

Answer: (c) trap a lot of air which is a bad conductor of heat

Question: Which of the following is not a good insulator of heat?

(a) Air

(b) Wood

(d) Wool

Answer: (c) Copper

Question: The process by which heat is transferred from the hotter end to the colder end of an object is known as

(a) Radiation

(b) Convection

(d) Insulation

Answer: (c) Conduction

Question: Sea breeze is an example of heat transfer by

(a) Conduction

(b) Convection

(d) Reflection

Answer: (b) Convection

FAQs on Extra Questions for Class 7 Science Chapter 4 Heat

What is heat in science class 7?

In Class 7 Science, heat is described as a form of energy that is transferred between objects due to a difference in their temperature. Heat flows from a hotter object to a colder one.

What I found interesting in chapter heat?

The interesting aspects of the heat chapter include understanding how heat is transferred through conduction, convection, and radiation, and learning about the applications of heat in our daily lives.

What is the SI unit of heat?

The SI unit of heat is the joule (J). However, heat is also commonly measured in calories, where 1 calorie is the amount of heat required to raise the temperature of 1 gram of water by 1°C.

How do we measure heat?

Heat is measured using devices called thermometers. The most common scale for measuring temperature is Celsius, but Fahrenheit and Kelvin are also used.

How is heat produced?

Heat can be produced through various processes, such as friction, burning of fuels, electrical resistance, chemical reactions, and absorption of sunlight.

Heat Class 7 Extra Questions Science Chapter 4

Long and Short Answer Type Extra Questions for Class 7 Science Chapter 4 Heat

Short Answer Types Questions with Answer for Class 7 Science Chapter 4 Heat

Long Answer Types Questions with Answer for Class 7 Science Chapter 4 Heat

Extra Multiple Choice Questions (MCQs) for Class 7 Science Chapter 4 Heat

FAQs on Extra Questions for Class 7 Science Chapter 4 Heat

What is heat in science class 7?

What I found interesting in chapter heat?

What is the SI unit of heat?

How do we measure heat?

How is heat produced?

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