Transfer Of Thermal Energy (continued)
Overview
A metal spoon left in a hot drink soon burns your fingers, warm air rises from a radiator to fill a room, and you feel the Sun's heat across empty space. These are the three ways thermal energy travels: conduction, convection and radiation. Knowing which one is at work, and often more than one at once, lets you explain almost every heating and cooling effect around you.
In this lesson you will explain everyday applications of conduction, convection and radiation, from cooking pans to heating a room. You will describe experiments that distinguish good and bad emitters and absorbers of infrared radiation, see how surface temperature and area control the rate of radiation, and explain complex cases such as a coal fire and a car radiator where more than one transfer matters.
Objectives
- Explain some of the basic everyday applications and consequences of conduction, convection and radiation, including: (a) heating objects such as kitchen pans (b) heating a room by convection
- [Supplement] Describe experiments to distinguish between good and bad emitters of infrared radiation
- [Supplement] Describe experiments to distinguish between good and bad absorbers of infrared radiation
- [Supplement] Describe how the rate of emission of radiation depends on the surface temperature and surface area of an object
- [Supplement] Explain some of the complex applications and consequences of conduction, convection and radiation where more than one type of thermal energy transfer is significant, including: (a) a fire burning wood or coal (b) a radiator in a car
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Lesson Evaluation
Congratulations on completing the lesson on Transfer Of Thermal Energy (continued). Now that you've explored the key concepts and ideas, it's time to put your knowledge to the test. This section offers a variety of practice questions designed to reinforce your understanding and help you gauge your grasp of the material.
You will encounter a mix of question types, including multiple-choice questions, short answer questions, and essay questions. Each question is thoughtfully crafted to assess different aspects of your knowledge and critical thinking skills.
Use this evaluation section as an opportunity to reinforce your understanding of the topic and to identify any areas where you may need additional study. Don't be discouraged by any challenges you encounter; instead, view them as opportunities for growth and improvement.
- Which method of thermal energy transfer can take place through a vacuum? A. conduction B. convection C. radiation D. none of these Answer: C
- A saucepan handle is made of plastic mainly because plastic is a A. good conductor B. good emitter C. poor conductor D. good absorber Answer: C
- Warm air rises from a heater because, when heated, the air becomes A. more dense B. less dense C. heavier D. cooler Answer: B
- Which surface is the best emitter of infrared radiation? A. shiny silver B. shiny white C. dull black D. polished metal Answer: C
- The rate at which an object emits radiation increases if its A. surface temperature falls B. surface area decreases C. surface temperature rises D. colour becomes shinier Answer: C
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Recommended Books
Further learning from open sources
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Textbook section
Radiation
You can feel the heat transfer from a fire and from the Sun. Similarly, you can sometimes tell that the oven is hot without touching its door or looking inside—it may just warm you as you walk by. The space between the Earth and the Sun is largely empty, without any possibility of heat transfer by c
"College Physics: Radiation" by OpenStax, OpenStax, Rice University, licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Source: https://openstax.org/books/college-physics/pages/14-7-radiation. Access for free at https://openstax.org/books/college-physics/pages/1-introduction
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Textbook section
Convection
Convection is driven by large-scale flow of matter. In the case of Earth, the atmospheric circulation is caused by the flow of hot air from the tropics to the poles, and the flow of cold air from the poles toward the tropics. (Note that Earth’s rotation causes the observed easterly flow of air in th
"College Physics: Convection" by OpenStax, OpenStax, Rice University, licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Source: https://openstax.org/books/college-physics/pages/14-6-convection. Access for free at https://openstax.org/books/college-physics/pages/1-introduction
Published by other organisations under open licences, credited as they ask. Links open their websites.
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