Chapter 12: Thermal Energy - Denton ISD
PerpetualMotion?The engine converts thechemical energy storedin the fuel and oxygeninto kinetic energy.Could we ever invent anengine that converts allthe energy into usefulenergy of motion? Look at the texton page 290 forthe answer.
CHAPTER12ThermalEnergyn Chapter 11, you learned that one of the forms of energy isstored energy. Energy can be stored in several ways. Yourbody stores energy as sugar in your body’s cells. Some heatingsystems store energy in hot-water tanks. A battery stores chemicalenergy released when a circuit is completed. In the last chapter, yousaw that a compressed spring can store energy.By converting stored energy into mechanical energy, an object,such as this racing car, can gain kinetic energy. However, it takesmore than the elastic potential energy of a compressed spring toaccelerate this high-tech racing car. It takes the energy stored inthe fuel combined with the oxygen in the air to get the car tomove faster than 350 km/h (217 mph) in a few seconds.In Chapter 10, you learned that work could transfer energyfrom the environment of a system. In this chapter, you’ll learnabout another way to transfer energy—the way that has transformedthe lives of people everywhere.The steam engine, the first invention that produced mechanicalenergy from fuel, transformed the United States from a society offarms to one with many factories in the 1800s. The steam enginecan be called a heat engine because it converts heat into work. Inthe case of the steam engine, the fuel source is outsidethe engine. However, you are probably much more familiar withheat engines that burn fuel inside the engine—internal combustion engines. One of these, the gasoline engine, precipitatedtremendous changes in the way people traveled, worked, and lived.Now, more than a century after its invention in 1876 by NikolausOtto in Germany, the gasoline engine is firmly entrenched inour society.IWHAT YOU’LL LEARN You will define temperature. You will calculate heattransfer. You will distinguish heatfrom work.WHY IT’S IMPORTANT Thermal energy provides theenergy to keep you warm, toprepare and preserve foodand to manufacture many ofthe objects you use on adaily basis.PHYSICSTo find out more about thermalenergy, visit the Glencoe ScienceWeb site at science.glencoe.com273
12.1OBJ ECTIVES Describe the nature ofthermal energy. Define temperature anddistinguish it from thermalenergy. Use the Celsius and Kelvintemperature scales andconvert one to the other. Define specific heat andcalculate heat transfer.Temperature andThermal EnergyEurope went through a “Little Ice Age” in the 1600s and1700s, when temperatures were lower than any other periodduring the previous one thousand years. Keeping warm was vitally important,and many people devoted themselves to the study of heat. One result wasthe invention of machines that used the energy produced by burning fuel todo useful work. These machines freed society from its dependence on theenergy provided solely by people and animals. As inventors tried to makethese machines more powerful and more efficient, they developed the science of thermodynamics, the study of heat.What makes a hot body hot?Internal combustion engines require very high temperatures to operate. These high temperatures are usually produced by burning fuel.Although the effects of fire have been known since ancient times, only inthe eighteenth century did scientists begin to understand how a hot bodydiffers from a cold body. They proposed that when a body is heated, aninvisible fluid called “caloric” is added to the body. Hot bodies containmore caloric than cold bodies. The caloric theory could explain observations such as the expansion of objects when heated, but it could notexplain why hands get warm when they are rubbed together.In the mid-nineteenth century, scientists developed a new theory toreplace the caloric theory. This theory is based on the assumption thatmatter is made up of many tiny particles that are always in motion. In ahot body, the particles move faster, and thus have greater kinetic energythan particles in a cooler body. This theory is called the kineticmolecular theory.The model of a solid shown in Figure 12–1 can help you understandthe kinetic-molecular theory. This model is a solid made up of tinyspherical particles held together by massless springs. The springs represent the electromagnetic forces that bind the solid together. The particles vibrate back and forth and thus have kinetic energy. The vibrationscompress and extend the springs, so the solid has potential energy aswell. The overall energy of motion of the particles that make up anobject is called the thermal energy of that object.Thermal Energy and TemperatureFIGURE 12–1 Molecules of asolid behave in some ways asif they were held together bysprings.274Thermal EnergyAccording to the kinetic-molecular theory, a hot body has more thermal energy than a similar cold body, shown in Figure 12–2. This meansthat, as a whole, the particles in a hot body have greater thermal energythan the particles in a cold body. It does not mean that all the particles in
a body have exactly the same energy. The particles have a range of energies,some high, others low. It is the average energy of particles in a hot bodythat is higher than that of particles in a cold body. To help you understandthis, consider the heights of students in a twelfth-grade class. The heightsvary, but you can calculate the average height. This average is likely to belarger than the average height of students in a ninth-grade class, eventhough some ninth-graders might be taller than some twelfth-graders.How can you determine the hotness of an object? “Hotness” is aproperty of an object called its temperature, and is measured on a definite scale. Consider two objects. In the one you call hotter, the particlesare moving faster. That is, they have a greater average kinetic energy.Because the temperature is a property of matter, the temperature doesnot depend on the number of particles in the object. Temperature onlydepends on the average kinetic energy of the particles in the object. Toillustrate this, consider two blocks of steel. The first block has a mass of1 kg and the second block has twice the mass of the first at 2 kg. If the1 kg mass of steel is at the same temperature as a 2 kg mass of steel, theaverage kinetic energy of the particles in the both blocks is the same. Butthe 2 kg mass of steel has twice the mass and the total amount ofkinetic energy of particles in the 2 kg mass is twice the amount in the1 kg mass. Total kinetic energy is divided over all the particles in anobject to get the average. Therefore, the thermal energy in an object isproportional to the number of particles in it, but its temperature isnot, as is shown in Figure 12–3.Hot bodyKHot KColdCold bodyFIGURE 12–2 Particles in a hotbody have greater kinetic andpotential energies than particlesin a cold body.Equilibrium and ThermometryHow do you measure your temperature? If you suspect that you havea fever, you may place a thermometer in your mouth and wait two orthree minutes. The thermometer then provides a measure of the temperature of your body.You are probably less familiar with the microscopic process involved inmeasuring temperature. Your body is hot compared to the thermometer,which means that the particles in your body have greater thermal energyand are moving faster. The thermometer is made of a glass tube. When thecold glass touches your hotter body, the faster-moving particles in yourskin collide with the slower-moving particles in the glass. Energy is transferred from your skin to the glass particles by the process of conduction,the transfer of kinetic energy when particles collide. The thermal energy ofthe particles that make up the thermometer increases and, at the sametime, the thermal energy of the particles in your skin decreases. As the particles in the glass become more energetic, they begin to transfer energyback to the particles in your body. At some point, the rate of transfer ofenergy back and forth between the glass and your body will become equaland both will be at the same temperature. Your body and the thermometer are then in thermal equilibrium. That is, the rate at which energyflows from your body to the glass is equal to the rate at which energy flows909080807070606050504040303020100050 mL100 mLFIGURE 12–3 Temperature doesnot depend on the number ofparticles in a body.12.1 Temperature and Thermal Energy275
Before thermal equilibriumHot body (A)Cold body (B)KA KBAfter thermal equilibriumfrom the glass to your body. Objects that are in thermal equilibrium are atthe same temperature, as is shown in Figure 12–4.A thermometer is a device that measures temperature. It is placed incontact with an object and allowed to come to thermal equilibriumwith that object. The operation of a thermometer depends on someproperty, such as volume, that changes with temperature. Many household thermometers contain colored alcohol that expands when heatedand rises in a narrow tube. The hotter the thermometer, the more thealcohol expands and the higher it rises. Mercury is another liquid commonly used in thermometers. In liquid crystal thermometers, such asthe one shown in Figure 12–5, a set of different kinds of liquid crystalsis used. Each crystal’s molecules rearrange at a specific temperaturewhich causes the color of the crystal to change, and creates an instrument that indicates the temperature by color.Temperature Scales: Celsius and KelvinKA KBFIGURE 12–4 Thermal energy istransferred from a hot body to acold body. When thermal equilibrium is reached, the transfer ofenergy between bodies is equal.FIGURE 12–5 Thermometersuse a change in physical properties to measure temperature.A liquid crystal thermometerchanges color with temperaturechange.276Thermal EnergyTemperature scales were developed by scientists to allow them tocompare their temperature measurements with those of other scientists.A scale based on the properties of water was devised in 1741 by theSwedish astronomer and physicist Anders Celsius. On this scale, nowcalled the Celsius scale, the freezing point of pure water is 0 degrees(0 C). The boiling point of pure water at sea level is 100 degrees(100 C). On the Celsius scale, the average temperature of the humanbody is 37 C. Figure 12–6 shows representative temperatures on thethree most common scales: Fahrenheit, Celsius, and Kelvin.The wide range of temperatures in the universe is shown inFigure 12–7. Temperatures do not appear to have an upper limit. Theinterior of the sun is at least 1.5 107 C and other stars are even hotter. Temperatures do, however, have a lower limit. Generally, materialscontract as they cool. If you cool an “ideal” gas, one in which the particles occupy a tremendously large volume compared to their own sizeand which don’t interact, it contracts in such a way that it occupies avolume that is only the size of the molecules at 273.15 C. At this temperature, all the thermal energy that can has been removed from the gas.It is impossible to reduce the temperature any further. Therefore, therecan be no temperature lower than 273.15 C. This is called absolutezero, and is usuallyrounded to 273 C.The Kelvin temperature scale is based onabsolute zero. Absolutezero is the zero point ofthe Kelvin scale. On theKelvin scale, the freezingpoint of water (0 C) is273 K and the boilingpoint of water is 373 K.
Each interval on this scale, called a kelvin, is equal to the size of oneCelsius degree. Thus, TC 273 TK. Very cold temperatures arereached by liquefying gases. Helium liquefies at 4.2 K, or 269 C. Evencolder temperatures can be reached by making use of special propertiesof solids, helium isotopes, or atoms and lasers. Using these techniques,physicists have reached temperatures as low as 2.0 10 9 K. 8010273.15270Temperature 1010090807060504030201032.000–25020Calculate Your Answer100Known:Unknown:Celsius temperature 25 CTK ?Strategy:Calculations:TK TC 273TK TC 273.0.000–10Convert 25 C to kelvins.Change Celsius temperatures toKelvin by using the relationship100.0010090310Example Problem –460–459.67FIGURE 12–6 The three mostcommon temperature scales areKelvin, Celsius, and Fahrenheit. 25 273 298 KCheck Your Answer Are your units correct? Temperature is measured in kelvins. Does the magnitude make sense? Temperatures on the Kelvin scaleare all larger than those on the Celsius scale.FIGURE 12–7 There is an extremely wide range of temperatures throughout theuniverse. Note the scale has been expanded in areas of particular interest.Interstellar space10–8 10–6 10–4 10–2 1Lowest temperaturein laboratorySurface of sunNuclear bombFlamesCenter of sunSupernova explosionsHuman body10Helium liquefies100103Superconductivity Life existsbelow this temperature104105106107Uncharged atoms existbelow this temperature1081091010Nuclei existbelow this temperatureTemperature (K)12.1 Temperature and Thermal Energy277
Practice ProblemsF.Y.I.Why are degrees used tomeasure temperature?Fahrenheit set up histemperature scale so thatthere were 180 degreesseparating the temperaturewhere water freezes to wherewater boils. This was becausethere are 180 degrees in astraight angle.1. Make the following conversions.a. 0 C to kelvinsc. 273 C to kelvinsb. 0 K to degrees Celsiusd. 273 K to degrees Celsius2. Convert the following Celsius temperatures to Kelvin temperatures.a. 27 Cd. 50 Cb. 150 Ce. 184 Cc. 560 Cf. 300 C3. Convert the following Kelvin temperatures to Celsius temperatures.a. 110 Kd. 402 Kb. 70 Ke. 323 Kc. 22 Kf. 212 K4. Find the Celsius and Kelvin temperatures for the following.a. room temperaturec. typical hot summer dayb. refrigerator temperatured. typical winter nightHeat and Thermal EnergyOne way to increase the temperature of an object is to place it in contact with a hotter object. The thermal energy of the hotter object isdecreased, and the thermal energy of the cooler object is increased. Energyalways flows from the hotter object to the cooler object. Energy neverflows from a colder object to a hotter object. Heat is the energy that flowsbetween two objects as a result of a difference in temperature. The symbol Q is used to represent the amount of heat. If Q has a negative value,heat has left the object; if Q has a positive value, heat has been absorbedby the object. Heat, like other forms of energy, is measured in joules.Thermal energy transfer You have already learned one way thatheat flows from a warmer body to a colder one. If you place one end ofa metal rod in a flame, it becomes hot. The other end also becomeswarm very quickly. Heat is conducted because the particles in the rod arein direct contact.A second means of thermal transfer involves particles that are not indirect contact. Have you ever looked in a pot of water just about to boil?You can see motion of water, as water heated by conduction at the bottom of the pot flows up and the colder water at the top sinks. Heat flowsbetween the rising hotter water and the descending colder water. Thismotion of fluid, whether liquid or gas, caused by temperature differences, is convection.The third method of thermal transfer, unlike the first two, does notdepend on the presence of matter. The sun warms us from over 150million kilometers via radiation, the transfer of energy by electromagnetic waves. These waves carry the energy from the hot sun to themuch cooler Earth.278Thermal Energy
Specific heat When heat flows into an object, its thermal energyincreases, and so does its temperature. The amount of the increasedepends on the size of the object. It also depends on the material fromwhich the object is made. The specific heat of a material is the amountof energy that must be added to the material to raise the temperature ofa unit mass one temperature unit. In SI units, specific heat, representedby C (not to be confused with C), is measured in J/kg K. Table 12–1provides values of specific heat for some common substances. For example, 903 J must be added to one kilogram of aluminum to raise the temperature one kelvin. The specific heat of aluminum is 903 J/kg K.Note that water has a high specific heat compared to those of other substances, even ice and steam. One kilogram of water requires the additionof 4180 J of energy to increase its temperature by one kelvin. The samemass of copper requires only 385 J to increase its temperature by onekelvin. The 4180 J of energy needed to raise the temperature of one kilogram of water by one kelvin would increase the temperature of the samemass of copper by 11 K. The high specific heat of water is the reason wateris used in car radiators to remove thermal energy from the engine block.The heat gained or lost by an object as its temperature changesdepends on the mass, the change in temperature, and the specific heatof the substance. The amount of heat transferred can be determinedusing the following equation.Heat TransferF.Y.I.Calorie and calorimeterare derived from calor,the Latin word for heat.Q mC T mC(Tfinal Tinitial)where Q is the heat gained or lost, m is the mass of the object, C is thespecific heat of the substance, and T is the change in temperature.When the temperature of 10.0 kg of water is increased by 5.0 K, the heatabsorbed, Q, isQ (10.0 kg)(4180 J/kg K)(5.0 K) 2.1 105 J.Because one Celsius degree is equal in magnitude to one kelvin, temperature changes can be measured in either kelvins or Celsius degrees.TABLE 12–1Specific Heat of Common SubstancesMaterialSpecific heatJ/kg Specific heatJ/kg K13024502352020418038812.1 Temperature and Thermal Energy279
Example ProblemHeat TransferA 0.400-kg block of iron is heated from 295K to 325K. How muchheat had to be transferred to the iron?Sketch the Problem Sketch the flow of heat into the blockof ironmQ T 0Calculate Your AnswerKnown:Strategy:Calculations:m 0.400 kgThe heat transferredis a product of themass, specific heat,and the temperature change.Q mC(Tf Ti)C 450 J/kg KTi 295 KTf 325 K (0.400 kg)(450 J/kg K)(325 295 K) 5.4 103 JUnknown:Q ?Check Your Answer Are your units correct? Heat is measured in joules. Does the sign make sense? Temperature increased so Q is positive. Is the magnitude realistic? Magnitudes of thousands of joules aretypical of solids with masses around 1 kg and temperaturechanges of tens of kelvins.Practice Problems5. How much heat is absorbed by 60.0 g of copper when itstemperature is raised from 20.0 C to 80.0 C?6. The cooling system of a car engine contains 20.0 L of water(1 L of water has a mass of 1 kg).a. What is the change in the temperature of the water if theengine operates until 836.0 kJ of heat are added?b. Suppose it is winter and the system is filled with methanol.The density of methanol is 0.80 g/cm3. What would be theincrease in temperature of the methanol if it absorbed836.0 kJ of heat?c. Which is the better coolant, water or methanol? Explain.280Thermal Energy
Heating UpProblemHow does a constant supply of thermalenergy affect the temperature of water?Materialshot plate (or Bunsen burner)250-mL ovenproof glass beakerwaterthermometerstopwatchgogglesapronData and ObservationsTimeTemperatureProcedure1. Turn your hot plate to a medium setting(or as recommended by your teacher).Allow a few minutes for the plate to heatup. Wear goggles.2. Pour 150 mL of room temperature waterinto the 250-mL beaker.3. Make a data and observations table.4. Record the initial temperature of the water.The thermometer must not touch the bottom or sides of the beaker.5. Place the beaker on the hot plate andrecord the temperature every 1.0 minute.Carefully stir the water before taking atemperature reading.6. Record the time when the water starts toboil. Continue recording the temperaturefor an additional 4.0 minutes.7. Carefully remove the beaker from the hotplate. Record the temperature of theremaining water.8. When you have completed the lab,dispose of the water as instructed by yourteacher. Allow equipment to cool beforeputting it away.Analyze and Conclude1. Analyzing Data Make a graph of temperature (vertical axis) versus time (horizontal axis). Use a computer or calculatorto construct the graph, if possible. What isthe relationship between variables?2. Interpreting Graphs What is the slopeof the graph for the first 3.0 minutes? Besure to include units.3. Relating Concepts What is the thermalenergy given to the water in the first3.0 minutes? Hint: Q mC T.4. Making Predictions Use a dotted line onthe same graph to predict what the graphwould look like if the same procedure wasfollowed with only half as much water.Apply1. Would you expect that the hot plate transferred energy to the water at a steady rate?2. Where is the energy going when the wateris boiling?12.1 Temperature and Thermal Energy281
Calorimetry: Measuring Specific tionSealedreactionchambercontainingsubstance and oxygenFIGURE 12–8 A calorimeterprovides a closed, isolated systemin which to measure energytransfer.A calorimeter, shown in Figure 12–8, is a device used to measurechanges in thermal energy. A calorimeter is carefully insulated so thatheat transfer is very small. A measured mass of a substance is placed inthe calorimeter and heated to a high temperature. The calorimeter contains a known mass of cold water at a measured temperature. The heatreleased by the substance is transferred to the cooler water. From theresulting increase in water temperature, the change in thermal energy ofthe substance is calculated.The operation of a calorimeter depends on the conservation of energyin isolated, closed systems. Energy can neither enter nor leave an isolatedsystem. As a result of the isolation, if the energy of one part of the systemincreases, the energy of another part must decrease by the same amount.Consider a system composed of two blocks of metal, block A and blockB, as in Figure 12–9a. The total energy of the system is constant.Conservation of Energy in a Calorimeter EA EB constantSuppose that the two blocks are initially separated but can be placed incontact. If the thermal energy of block A changes by an amount EA,then the change in thermal energy of block B, EB, must be related bythe following equation. EA EB 0Which means that the following relationship is true. EA EBThe change in energy of one block is positive, while the change inenergy of the other block is negative. If the thermal energy change ispositive, the temperature of that block rises. If the change is negative,the temperature falls.Assume that the initial temperatures of the two blocks are different. Whenthe blocks are brought together, heat flows from the hotter block to thecolder block, as shown in Figure 12–9b. The flow continues until the blocksare in thermal equilibrium. The blocks then have the same temperature.AaEA E EBEB E – E2EABFIGURE 12–9 The total energyfor this system is constant.282Thermal EnergybE A B E E E – E 2EInsulation
In a calorimeter, the change in thermal energy is equal to the heattransferred because no work is done. Therefore, the change in energy canbe expressed by the following equation. E Q mC TThe increase in thermal energy of block A is equal to the decrease inthermal energy of block B. Thus, the following relationship is true.mACA TA mBCB TB 0The change in temperature is the difference between the final and initial temperatures, that is, T Tf Ti. If the temperature of a blockincreases, Tf Ti, and T is positive. If the temperature of the blockdecreases, Tf Ti, and T is negative. The final temperatures of the twoblocks are equal. The equation for the transfer of energy isF.Y.I.For many years, thermalenergy was measured incalories. Calories are notpart of the SI system ofmeasurements, so today,thermal energy is measuredin joules. One calorie isequal to 4.18 joules.mACA(Tf TAi) mBCB(Tf TBi) 0.To solve for Tf, expand the equation.mACATf mACATAi mBCBTf mBCBTBi 0Tf (mACA mBCB) mACATAi mBCBTBi.mACATAi mBCBTBiTf mACA mBCBExample ProblemHeat Transfer in a CalorimeterA calorimeter contains 0.50 kg of water at 15 C. A 0.040-kg block of zincat 115 C is placed in the water. What is the final temperature of the system?Sketch the Problem Let zinc be sample A and water be sample B. Sketch the transfer of heat from hotter zinc to cooler water.QmAmB TA 0 TB 0Calculate Your AnswerKnown:Unknown:Zinc mA 0.040 kgCA 388 J/kg CTAi 115 CWater mB 0.50 kgTf ?CB 4180 J/kg ºCTBi 15 CmACATAi mBCBTBiStrategy: Determine final temperature using Tf .mACA mBCB(0.040 kg)(388 J/kg C)(115 C) (0.50 kg)(4180 J/kg C)(15 C)Calculations: Tf (0.040 kg)(388 J/kg C) (0.50 kg)(4180 J/kg C)(1.78 103 3.14 104)J 16 C(15.5 2.09 103)J/ CContinued on next page12.1 Temperature and Thermal Energy283
Check Your Answer Are the units correct? Temperature is measured in C. Is the magnitude realistic? The answer is between the initialtemperatures of the two samples and closer to water.Practice ProblemsPocket LabMeltingLabel two foam cups A and B.Measure 75 mL of roomtemperature water into each ofthe two cups. Add an ice cubeto cup A. Add ice water to cupB until the water levels areequal. Measure the temperatureof each cup at one minuteintervals until the ice has melted.Analyze and Conclude Do thesamples reach the same finaltemperature? Why?12.17. A 2.00 102-g sample of water at 80.0 C is mixed with2.00 102 g of water at 10.0 C. Assume no heat loss to thesurroundings. What is the final temperature of the mixture?8. A 4.00 102-g sample of methanol at 16.0 C is mixed with4.00 102 g of water at 85.0 C. Assume that there is no heatloss to the surroundings. What is the final temperature of themixture?9. A 1.00 102-g brass block at 90.0 C is placed in a plastic foamcup containing 2.00 102 g of water at 20.0 C. No heat is lostto the cup or the surroundings. Find the final temperature of themixture.10. A 1.00 102-g aluminum block at 100.0 C is placed in1.00 102 g of water at 10.0 C. The final temperature of themixture is 25.0 C. What is the specific heat of the aluminum?Section Review1. Could the thermal energy of a bowl ofhot water equal that of a bowl of coldwater? Explain.2. On cold winter nights before centralheating existed, people often placedhot water bottles in their beds. Whywould this be more efficient thanwarmed bricks?3. If you take a spoon out of a cup ofhot coffee and put it in your mouth,you are not likely to burn yourtongue. But, you could very easily284Thermal Energyburn your tongue if you put the hotcoffee in your mouth. Why?4.Critical Thinking You use an aluminumcup instead of a plastic foam cup asa calorimeter, allowing heat to flowbetween the water and the environment. You measure the specific heatof a sample by putting the hot objectinto room temperature water. Howmight your experiment be affected?Would your result be too large ortoo small?
Change of State and Laws ofThermodynamicsf you rub your hands together, you exert a force andmove your hands over a distance. You do workagainst friction. Your hands start and end at rest, sothere is no net change in kinetic energy. They remain thesame distance above Earth, so there is no change in potential energy. Yet,if the law of conservation of energy is true, then the energy transferred bythe work you did must have gone somewhere. You notice that your handsfeel warm; their temperature has increased. The energy to do the workagainst friction has changed form to thermal energy.IChange of State12.2OBJ ECTIVES Define heats of fusion andvaporization. State the first and secondlaws of thermodynamics. Define heat engine, refrigerator, and heat pump. Define entropy.The three most common states of matter are solids, liquids, andgases, as shown in Figure 12–10. As the temperature of a solid is raised,it will usually change to a liquid. At even higher temperatures, it willbecome a gas. How can we explain these changes? Consider a materialin a solid state. Your simplified model of the solid consists of tiny particles bonded together by massless springs. These massless springs represent the electromagnetic forces between the particles. When the thermal energy of a solid is increased, the motion of the particles isincreased and the temperature increases.FIGURE 12–10 The three statesof water are represented in thisphotograph. The gaseous state,water vapor, is dispersed in theair and is invisible until itcondenses.12.2 Change of State and Laws of Thermodynamics285
FIGURE 12–11 A plot oftemperature versus heat addedwhen 1 g of ice is initiallyconverted to steam.DTemperature (K)373EWater watervapor323WatervaporWater273BCIce water243A62.7395.7813.73073Heat (J)HELP WANTEDHVAC TECHNICIANKnowledge of thermodynamics; ability to read blueprints,specifications and manuals;familiarity with current products, procedures, tools, andtest equipment; and ability towork hard in sometimesphysically demanding conditions make you an ideal candidate for this position.Knowledge of all kinds ofheating, ventilation, and airconditioning systems isrequired. Work your way upinto other positions based onyour work performance andcompletion of further training. For information contact:Associated Builders andContractors1300 N. Seventeenth StreetSuite 800Rosslyn, VA 22209286Thermal EnergyFigure 12–11 diagrams this process throughout all the changes ofstate as thermal energy is added to 1.0 g of H2O starting at an initialtemperature of 243 K and continuing until the temperature is 473 K.Between points A and B, the ice is warmed to 273 K. At some point, theadd
energy back and forth between the glass and your body will beco me equal and both will be at the same temperature. Your body and the thermome-ter are then in thermal equilibrium.That is, the rate at which energy flows from your body to the glass is equal to the rate at which energy flows 12.1 Temperature and Thermal Energy 275 50 mL 100 mL 0 90 .
Part One: Heir of Ash Chapter 1 Chapter 2 Chapter 3 Chapter 4 Chapter 5 Chapter 6 Chapter 7 Chapter 8 Chapter 9 Chapter 10 Chapter 11 Chapter 12 Chapter 13 Chapter 14 Chapter 15 Chapter 16 Chapter 17 Chapter 18 Chapter 19 Chapter 20 Chapter 21 Chapter 22 Chapter 23 Chapter 24 Chapter 25 Chapter 26 Chapter 27 Chapter 28 Chapter 29 Chapter 30 .
changes to thermal energy. Thermal energy causes the lamp's bulb to become warm to the touch. Using Thermal Energy All forms of energy can be changed into thermal energy. Recall that thermal energy is the energy due to the motion of particles that make up an object. People often use thermal energy to provide warmth or cook food. An electric space
TO KILL A MOCKINGBIRD. Contents Dedication Epigraph Part One Chapter 1 Chapter 2 Chapter 3 Chapter 4 Chapter 5 Chapter 6 Chapter 7 Chapter 8 Chapter 9 Chapter 10 Chapter 11 Part Two Chapter 12 Chapter 13 Chapter 14 Chapter 15 Chapter 16 Chapter 17 Chapter 18. Chapter 19 Chapter 20 Chapter 21 Chapter 22 Chapter 23 Chapter 24 Chapter 25 Chapter 26
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using the words kinetic energy, thermal energy, and temperature. Use the space below to write your description. 5. Brainstorm with your group 3 more examples of thermal energy transfer that you see in everyday life. Describe where the thermal energy starts, where the thermal energy goes, and the results of the thermal energy transfer.
DEDICATION PART ONE Chapter 1 Chapter 2 Chapter 3 Chapter 4 Chapter 5 Chapter 6 Chapter 7 Chapter 8 Chapter 9 Chapter 10 Chapter 11 PART TWO Chapter 12 Chapter 13 Chapter 14 Chapter 15 Chapter 16 Chapter 17 Chapter 18 Chapter 19 Chapter 20 Chapter 21 Chapter 22 Chapter 23 .
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