Transfer of Thermal Energy

Transfer of Thermal Energy Physical Science Carly Andrade 2023 Name: ______________________________Grade:___ Class Period: ___ Date:____________ Essential Question: What is thermal energy and how is it transferred? Instructions: Read the selection and answer the questions. The heat source for our planet is the sun. Energy from the sun is transferred through space and through the earth's atmosphere to the earth's surface. Since this energy warms the earth's surface and atmosphere, some of it is or becomes heat energy. There are three ways heat is transferred, into the atmosphere: 1. radiation 2. Conduction 3. convection Radiation If you have stood in front of a fireplace or near a campfire, you have felt the heat transfer known as radiation. The side of you nearest the fire warms, while your other side remains unaffected by the heat. Although you are surrounded by air, the air has nothing to do with this transfer of heat. Heat lamps, that keep food warm, work in the same way. Radiation is the transfer of heat energy by electromagnetic radiation. Most of the electromagnetic radiation that comes to the earth from the sun is in the form of visible light. Light is made of waves of different frequencies. The frequency is the number of instances that a repeated event occurs, over a set time. In electromagnetic radiation, the frequency is the number of times an electromagnetic wave moves past a point each second. Our brains interpret these different frequencies into colors, including red, orange, yellow, green, blue, indigo, and violet. When the eye views all these different colors at the same time, it is interpreted as white. Waves from the sun which we cannot see are infrared, which have lower frequencies than red, and ultraviolet, which have higher frequencies than violet light. Most of the solar radiation is absorbed by the atmosphere and much of what reaches the earth's surface is radiated back into the atmosphere to become heat energy. Dark colored objects such as asphalt absorb more of the radiant energy and warm faster that light colored objects. Dark objects also radiate their energy faster than lighter colored objects. Conduction Conduction is the transfer of heat energy from one substance to another or within a substance. Have you ever left a metal spoon in a pot of soup being heated on a stove? After a short time the handle of the spoon will become hot. This is due to transfer of heat energy from molecule to molecule or from atom to atom. Also, when objects are welded together, the metal becomes hot (the orange-red glow) by the transfer of heat from an arc. This is called conduction and is a very effective method of heat transfer in metals. However, air conducts heat poorly. Convection Convection is the transfer of heat energy in a fluid. This type of heating is most commonly seen in the kitchen when you see liquid boiling. Air in the atmosphere acts as a fluid. The sun's radiation strikes the ground, thus warming the rocks. As the rock's temperature rises due to conduction, heat energy is released into the atmosphere, forming a bubble of air which is warmer than the surrounding air. This bubble of air rises into the atmosphere. As it rises, the bubble cools with the heat contained in the bubble moving into the atmosphere. As the hot air mass rises, the air is replaced by the surrounding cooler, more dense air, what we feel as wind. These movements of air masses can be small in a certain region, such as local cumulus clouds, or large cycles in the troposphere, covering large sections of the earth. Convection currents are responsible for many weather patterns in the troposphere. infohost.nmt.edu/~klathrop/ES/Earthsystems/Worksheets QUESTIONS: 1. Radiation is the only type of energy that can travel through space. The Earth gets its heat primarily from the Sun. The Earth gets its heat from what source? ___________________________________________________ 2. What are the three ways in which heat is transferred? The three ways in which heat is transferred are conduction, convection, and radiation. ______________________________________________________________________________________ ______________________________________________________________________________________ 3. How is heat energy transferred in radiation? Heat energy is transferred in radiation through electromagnetic waves that travel through space. ______________________________________________________________________________________ ______________________________________________________________________________________ 4. What does it mean by frequency? Frequency refers to the number of complete cycles of a wave that occur in a given unit of time. ______________________________________________________________________________________ ______________________________________________________________________________________ 5. How do our brains interpret the different frequencies of visible light? Our brains interpret the different frequencies of visible light as different colors. ______________________________________________________________________________________ ______________________________________________________________________________________ 7. What color do we see when we see all the different spectrum or colors at the same time? When we see all the different spectrum or colors at the same time, we perceive the color white. ______________________________________________________________________________________ ______________________________________________________________________________________ 8. Which can absorb more radiant energy dark colored objects or light colored objects? Dark-colored objects can absorb more radiant energy compared to light-colored objects. ______________________________________________________________________________________ ______________________________________________________________________________________ 9. What is conduction? Conduction is the transfer of heat through direct contact between particles of matter. ______________________________________________________________________________________ ______________________________________________________________________________________ 10. How is heat transferred in conduction? Heat is transferred in conduction by the collision of molecules or atoms transferring thermal energy from one to another. ______________________________________________________________________________________ ______________________________________________________________________________________ 11. Which can conduct heat faster metal or air ( gas)? Explain your answer. Think! Metals conduct heat faster than air because they have free electrons that can move and transfer thermal energy ______________________________________________________________________________________ ______________________________________________________________________________________ more efficiently. In contrast, air is a poor conductor because its molecules are spaced further apart, limiting the transfer of heat through collisions. What is a Fluid? A fluid is anything that would spill or float away if it weren't in a container (unless it's big enough to be held together by gravity like a star). If you can stir it up with a spoon or blow it through a straw, it's a fluid. Water is a fluid and so is air. In fact, all liquids and gases are fluids. In space and inside stars there's also another kind of fluid called a plasma 12. What is convection? Convection is the transfer of heat through the movement of a fluid, such as air or water. ______________________________________________________________________________________ ______________________________________________________________________________________ 13. How is heat transferred in convection? Heat is transferred in convection through the movement of fluid particles. When a fluid is heated, its particles become ______________________________________________________________________________________ less dense and rise, while cooler, denser fluid descends to take its place, creating a continuous circulation pattern. ______________________________________________________________________________________ 14. Give examples of fluid. Examples of fluids include water, air, and gases like helium and nitrogen. ______________________________________________________________________________________ ______________________________________________________________________________________ 15. What is responsible for the weather patterns in the troposphere? The movement of air and water in the troposphere, influenced by factors such as temperature, pressure, ______________________________________________________________________________________ and Earth's rotation, is responsible for creating weather patterns in this atmospheric layer. ______________________________________________________________________________________ Radiation is energy that travels in waves. The intensity of the energy depends on the size or amplitude and frequency of the waves. Study the chart of the electromagnetic spectrum and answer the following questions. The Electromagnetic Spectrum from 400 to 700 16. What is the range of wavelengths for visible light? __________________nm from 430 to 750 (THz) 17. What is the range of frequencies of visible light? ______________________ Red light 18. Which color of visible light has the longest wavelength? ________________ Violet light 19. Which color of visible light has the shortest wavelength? _______________ High frequency has more energy low frequency. 20. Which has more energy low frequency or high frequency? than ______________ Nuclear reactions, such as those occurring in ___________________________________ 21. What can produce gamma rays? radioactive decay or during certain nuclear reactions in stars. The diagram below shows the frequency and wavelength of various types of electromagnetic energy. X-ray ______________22. . Which type of electromagnetic wave has a wavelength of approximately 10-10 meters and a frequency of 1018 hertz? radar X ray radio infrared D ______________23. Which of the following aspects of electromagnetic radiation best explains why electromagnetic radiation is both useful and harmful to humans? A. Electromagnetic radiation can be described in terms of both wavelength and frequency. B. Electromagnetic radiation travels at the speed of light. C. Electromagnetic radiation can travel through a vacuum. D. Electromagnetic radiation is energy and can interact with matter. The diagram shows the electromagnetic spectrum and some of the different types of radiant energy. Visible light _______________24. The component of the spectrum between ultraviolet light and infrared light interacts with the human eye allowing us to see. What is this part of the electromagnetic spectrum called? communication waves x-rays microwaves visible light Ultraviolet light _______________25. The sun emits all the different types of radiant energy on the electromagnetic spectrum. The Earth does not receive the full impact of all this radiation. The ozone layer in the Earth's atmosphere absorbs and helps to block which type of radiant energy? x-rays Ultraviolet light Infrared light Radio waves Wavelength _______________26. Scientists have divided the energy in the electromagnetic spectrum in different categories. Each category is defined by a different ____. visibility ray spectrum wavelength Gamma ray waves _______________27. As the frequency of the radiation increases so does the energy in that type of radiation. Which form of radiation has the highest frequency and therefore most energy? gamma ray waves ultraviolet light waves infrared waves radio waves R ________28. Which letter in the diagram below identifies a wavelength? P Q R S Ultraviolet ________29. Which form of solar radiation causes sunburn? X-rays Infrared Visible Ultraviolet Radiators of heat _______30. In general, good absorbers of electromagnetic radiation are also good ___. refractors of heat radiators of heat reflectors of heat convectors of heat The metric system is the world standard for measurement. Not only is it used by scientists throughout the world, but most nations have adopted it as their standard of measurement. All of the measurements done in this course will use the metric system. Metric Prefixes FACTOR 1,0E+24 1,0E+21 1,0E+18 1,0E+15 1,0E+12 1,0E+9 1,0E+6 1,0E+3 1,0E+2 1,0E+1 1,0E-1 1,0E-2 1,0E-3 1,0E-6 1,0E-9 1,0E-12 1,0E-15 1,0E-18 1,0E-21 ...or in full ... 1 000 000 000 000 000 000 000 000 1 000 000 000 000 000 000 000 1 000 000 000 000 000 000 1 000 000 000 000 000 1 000 000 000 000 1 000 000 000 1 000 000 1 000 100 10 0,1 0,01 0,001 0,000 001 0,000 000 001 0,000 000 000 001 0,000 000 000 000 001 0,000 000 000 000 000 001 0,000 000 000 000 000 000 001 or in words septillion sextillion quintillion quadrillion trillion billion million thousand hundred ten tenth hundredth thousandth millionth billionth trillionth quadrillionth quintillionth sextillionth SI PREFIX SI SYMBOL yottazettaexapetateragigamegakilohectodecadecicentimillimicronanopicofemtoattozepto- Y Z E P T G M k h da d c m µ n p f a z 1,0E-24 0,000 000 000 000 000 000 000 001 septillionth yocto- y