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Heat Energy Transfer. Conduction, Convention & Radiation. Essential Standard. 6.P. 3 Understand characteristics of energy transfer and interactions of matter and energy. Clarifying Objective.
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Heat Energy Transfer Conduction, Convention & Radiation
Essential Standard • 6.P.3 Understand characteristics of energy transfer and interactions of matter and energy.
Clarifying Objective • 6.P.3.1 Illustrate the transfer of heat energy from warmer objects to cooler ones using examples of conduction, radiation and convection and the effects that may result.
Essential Questions • What are the different ways that energy be transferred?
Heat Transfers • Heat atoms are always looking to try to find cold atoms • Heat atoms can give cold atoms their heat 3 different ways • These 3 ways are called • Conduction • Convection • Radiation
Why Does Heat Transfer • Heat transfers from object to object because EVERY OBJECT IS TRYING TO BECOME WARMER • Objects try to become what the dominate temperature is (room)
Conduction • Conduction is the first way atoms with heat in them will transfer them to cold atoms • Conduction is the heat transfer of two solids joined together through a conductor (direct contact)
Conduction • A conductor is what actually what actually transfers the heat from one solid to another solid • Conduction mediums are always solids (they only transfer heat through solids)
Conductor • Conductors are mediums that will transfer heat from one solid to another • Hot atoms move through the conductors to transfer their heat to cold atoms • Some items are better conductors than others
Conductor • Solids are always the best conductors because their atoms are attached and not spread out so the heat can move through them better • Gases are the worst conductors because their atoms are so spread out and it will take longer for them to bump into each other • Metals are the best conductors because they are solids and their atoms have the most density
How Does Conduction Happen? • Solid with hot atoms look for cold solid atoms • The conductor is placed between the solid hot atoms & the solid cold atoms • Hot atoms (excited) vibrate & hit each other & move through the conductor
How Does Conduction Happen? • Once the hot atoms have moved through the conductor they contact the cold atoms of the other solid • They transfer the heat from their atoms (hot atoms) to the cold atoms and warm them up • Now all atoms in both solids are warm
Conduction (Example) • http://www.youtube.com/watch?v=Gyj444FK0zs
Convection • Convection is the moving of heat through gas or liquid mediums • Convection will only transfer heat through gasses or liquids
Convection Process • http://www.youtube.com/watch?v=liKcJKjvFcY • 0:00-1:36
How Does Convection Happen? • Hot atoms form and become excited and start to vibrate • As they vibrate the hot atoms rise because the atoms begin to separate and become less dense • The hot atoms that rise push the cold atoms to the bottom and they are heated
How Does Convection Happen? • Then those atoms rise and push the next batch of cold dense atoms to the bottom to be warmed again • The process continues and forms a CONVECTION CURRENT
Convection Example • http://www.youtube.com/watch?v=Gyj444FK0zs
Radiation • Transfer of heat atoms through electromagnetic wave motion • Radiation involves light photons not atom particles • All waves on the Electromagnetic Spectrum will transfer heat through radiation • Radio Waves • Microwaves • Infrared Waves • Ultraviolet Waves • X-Ray Waves • Gamma Waves
Radiation (Heat Absorption) • About 50% (half) of the radiation heat transfer comes from VISIBLE LIGHT part of the spectrum • The amount of heat absorbed through radiation depends on… • Intensity of the waves (visible waves are most intense) • Color of the object the radiation wave is hitting • This is why darker colors absorb more heat than lighter colors
How Does Radiation Happen? • Waves from the Electromagnetic Spectrum radiate heat • The electromagnetic waves carry the heat through any medium • The heat waves hit the object and warm it up
Radiation Example • Campfires radiate heat through light waves from the electromagnetic spectrum • Microwaves do the same thing
Radiation Video • http://www.youtube.com/watch?v=GYUN8o4eJ24
Essential Questions • Get with a partner and answer… • What are the different ways that energy be transferred?
Important Points • Heat transfer occurs because all objects are trying to become warmer • Conduction is heat transferring through direct contact between objects • Conduction must have conductors to occur • Metals are good conductors because their atoms are close together • Conduction only occurs through two SOLIDS • Convection is heat transfer through currents • Convections currents occur in liquids & gasses only • Radiation is the transfer of heat through photons on waves • It does not include atoms • Radiation depends on how INTENSE the wave is & the COLOR of the object it is warming