Heat Transfer
Conduction, Convection, and Radiation
Thermal Energy
- Whenever energy appears in one place, it must have disappeared from another. Whenever energy is lost from somewhere, it must have gone somewhere else. Sometimes when energy appears to be lost, it actually has been transferred to a system that is so large that the effect of the transferred energy is imperceptible.
- Energy can be transferred from one system to another (or from a system to its environment) in different ways: 1) thermally, when a warmer object is in contact with a cooler one; 2) mechanically, when two objects push or pull on each other over a distance; 3) electrically, when an electrical source such as a battery or generator is connected in a complete circuit to an electrical device; or 4) by electromagnetic waves.
- Thermal energy is transferred through a material by the collisions of atoms within the material. Over time, the thermal energy tends to spread out through a material and from one material to another if they are in contact. Thermal energy can also be transferred by means of currents in air, water, or other fluids. In addition, some thermal energy in all materials is transformed into light energy and radiated into the environment by electromagnetic waves; that light energy can be transformed back into thermal energy when the electromagnetic waves strike another material. As a result, a material tends to cool down unless some other form of energy is converted to thermal energy in the material.
Questions:
What is thermal (heat) energy?
What are the methods of thermal energy transfer from one object/subject to another?
What is conduction?
What are some examples of conduction?
What is radiation?
What are some examples of radiation?
What is convection?
What are some examples of convection?
What is the pattern in which thermal energy moves within a system?
What are some examples of thermal energy moving in a pattern within a system?
Why does thermal energy move in a predictable pattern within a system?
What is meant by the law of conservation of energy in the context of the transfer of thermal energy?
Key Content Vocabulary:
- Conduction – transfer of heat through direct contact from a warmer substance to a cooler substance
- Convection – transfer of thermal energy, in a liquid or gas, in which the warmer substance rises and the cooler substance sinks; forms a current
- Energy – the ability to cause change or do work
- Energy transfer – transfer of energy from one object or substance to another
- Law of conservation of energy – states that energy is neither created or destroyed
- Temperature – measure of the average kinetic energy of the particles in a substance
- Thermal energy – a form of kinetic energy resulting from the motion of particles that is transferred as heat; associated with the temperature of substances
https://www.youtube.com/watch?v=6sUOMds_zmE
https://www.youtube.com/watch?v=w_IbPRNZ6ho
https://www.youtube.com/watch?v=8E1gx_vZMcM
https://www.youtube.com/watch?v=N8mCn8f3za0
https://www.youtube.com/watch?v=7Y3mfAGVn1c
https://www.youtube.com/watch?v=YK7G6l_K6sA
https://www.youtube.com/watch?v=yUEPGMnRqGs
https://www.youtube.com/watch?v=dipJir9ZpFU
https://www.youtube.com/watch?v=Akd7MMRKDwc&list=PL7AaWimVwIFPKfhSdEvdrQSmKIkqtp4uj
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https://www.youtube.com/watch?v=_fcXL61NZS0&list=PL7AaWimVwIFPKfhSdEvdrQSmKIkqtp4uj&index=5
Thermal Energy and Ocean Currents
- Thermal energy carried by ocean currents has a strong influence on climates around the world. Areas near oceans tend to have more moderate temperatures than they would if they were farther inland but at the same latitude because water in the oceans can hold a large amount of thermal energy.
https://www.youtube.com/watch?v=Gyj444FK0zs
https://www.youtube.com/watch?v=tZliZyoYT80
https://www.youtube.com/watch?v=125KoXlTD9Q
https://www.youtube.com/watch?v=eKC5ycwRDsw
https://www.youtube.com/watch?v=O-lHJ5mlEhI
Thermochromatic Ink
a type of dye that changes color when temperatures increase or decrease
https://www.youtube.com/watch?v=IZT1v_Cf0rE
Heat Transfer Song