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[PDF] How heat is transferred
Heat (thermal energy) always moves from hot places to cold places This is called heat transfer Sometimes you want to make it easy for heat to go from one
[PDF] The movement of heat from a warmer object to a colder one
Heat Transfer: The movement of heat from a warmer object to a colder one – when two substances at different temperatures are mixed together, heat flows from
[PDF] Thermal Energy Transfer
Thermal energy is always shared between objects that touch each other, like your hand and a hamburger The thermal energy always travels from the item with the
[PDF] TEACHER BACKGROUND: SPECIFICS OF HEAT TRANSFER
The transfer of heat by radiation involves the carrying of energy from an origin to the space surrounding it The energy is carried by electromagnetic waves and
[PDF] Heat Transfer: Conduction, Convection, and Radiation
that are different temperatures, heat will always move OUT of (Remember, we learned that energy transfer is when energy moves from one thing or place to
[PDF] 31 & 32 Forms of Heat Transfer & the 2nd Law of Thermodynamics
Thermal Energy always flows from hot to cold From the plastic bottle to the ocean or From the ocean to the plastic bottle 5 Will the
[PDF] HEAT TRANSFER
Heat transfer always occurs from a hot body to a cold one, a result of the second law of thermodynamics Transfer of thermal energy occurs mainly
[PDF] Heat Transfer - Shobhit University
determination of the rates of such energy transfers is the heat transfer The transfer of energy as heat is always from the higher-temperature medium to the
[PDF] Heat and Thermal Energy - Center Grove
to be transferred until both objects are the same temperature Transfer of Heat When heat is transferred, thermal energy always moves from warmer to cooler
![[PDF] 31 & 32 Forms of Heat Transfer & the 2nd Law of Thermodynamics](https://pdfprof.com/EN_PDFV2/Docs/PDF_3/127918_33_13_2HeatSol_docx.pdf.jpg "[PDF] 31 & 32 Forms of Heat Transfer & the 2nd Law of Thermodynamics")
127918_33_13_2HeatSol_docx.pdf 3.1 & 3.2 Forms of Heat Transfer & the 2nd Law of Thermodynamics
3.1. Explain how heat energy is transferred by convection, conduction, and/or radiation.
Page 479-481 in Text. Section 16.2
3.2. Explain how heat energy will move from a higher temperature to a lower temperature until equilibrium is
reached. Page 482-483 in Text. Section 16.2 to/from Temperature difference temperature Cold warmer Thermal equilibrium equilibrium Conduction Convection Radiation3.1 FORMS OF HEAT TRANSFER
There are three forms of heat transfer. One thing drives heat transfers it is a difference in temperature.
CONDUCTION - this form of heat transfer requires that two objects be in contact. Thermal Energy flows from the warmer object to the cooler object. The greater the temperature difference the greater the rate of energy transfer.There is no material flow, only energy flows.
2 requirements for Energy Transfer through Conduction = Physical Contact and
a temperature difference. CONVECTION - this form of heat transfer requires with a fluid which changes density with temperature. In this case the fluid (air) becomes less dense as it is warmed, this density change causes it to rise and cool fluid (air) takes its place. This motion is convection current. Energy is transferred to the air which moves. So the fluid (air) and Energy are moving.2 requirements for Energy Transfer through Convection = Physical Contact
with a fluid and a temperature difference. RADIATION - This is the only form of heat transfer that does not require contact between substances. No contact is required because the energy is transferred as Electromagnetic waves. Specifically the waves are Infrared light. Radiation can transfer energy across space as in the example of the sun heating up the containers.Things that effect rate of heat transfer:
Sight line - Can the objects ͞see" one another͍ Color - Some colors absorb light better than others. Temperature difference - There must be a temperature difference.2 requirements for Energy Transfer through Radiation = Line of sight and a
temperature difference. Forms of Heat Transfer Lesson: If you are absent this is a good source. http://www.wisc-online.com/Objects/ViewObject.aspx?ID=sce304 HEAT EXCHANGE- When an object has a higher temperature than our body and we touch it we can feel adifference and energy is transferred to our body. When an object has a cooler temperature than our body
and we touch it we can feel a difference and energy is transferred from our body. This leads us to one Method of Stating the Second Law of Thermodynamics: ͞Thermal Energy (HEAT) can only flow from objects of higher temperature to objects of lower temperature." THERMAL EQUILIBRIUM - Notice that the only requirement shared by all forms of energy transfer is atemperature difference between the objects. Any time this is present the objects are not at equilibrium.
Nature likes equilibrium so the objects will transfer energy until they are at Thermal Equilibrium. Thermal
Equilibrium occurs when the two objects have the same temperature. Look at the two tanks holding water in the diagram. The tanks have equal quantity of water but different level/depth. If the valve is opened so water can move from one to another which direction will water flow? To the Left or To the right. Why?Water flows down hill.
The temperature of objects transferring thermal energy is similar to the height of the water in the tanks.When will the water stop flowing?
The water will stop flowing when the depth of the tanks match. This diagram illustrates a warm object connected to a cooler object. Which direction will the heat flow?When will heat stop flowing in a thermal system?
When the temperatures are equal.
In the case of the hot cup
Thermal Energy is transferred
from the cup to the person͛s hand.In the case of the cold cup
Thermal Energy is transferred
to the cup from the person͛s hand. Last Name___________________________ First Name______________________3.1 & 3.2 FORMS OF HEAT TRANSFER
1. What requirement do all forms of heat transfer require? Temperature Difference
2. What is it called when two objects have the same temperature? Thermal Equilibrium
3. Which has more thermal energy, a plastic water bottle with hot water (90 C) or the ocean at 15 C?
The ocean, because its mass is so large.
4. If the plastic bottle of hot water was placed in the ocean which direction would the heat flow? (Choose one and
explain) The energy would flow from the bottle to the ocean. Thermal Energy always flows from hot to cold.
From the plastic bottle to the ocean or From the ocean to the plastic bottle.
5. Will the ocean͛s temperature change much͍ No Why ( or Why not)? Its mass it so large.
6. What form of heat transfer is occurring between the hot water bottle and the ocean? Conduction.
7. When you put your hand in the snow which direction is the heat flowing?
From your hand to the snow or From the snow to your hand.8. A person is baking potatoes tries an experiment. He/she has two identical potatoes. They are placed in the oven
together to be baked. One has a large nail pushed through it. Which potato will heat up more quickly? (Explain your
answer)This is an interesting situation. The nail will conduct the heat better than the potato itself. The potato with the nail
will cook more quickly.