Download Heat and Heat Transfer By Kevin Lei heat is thermal energy heat

Heat and Heat Transfer
By Kevin Lei
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heat is thermal energy
heat from a source can be transferred three ways:
o radiation
 heat transferred from a source through “space” between objects
 e.g. the sun heating the planets, done through indirect contact
o conduction
 heat transferred from one object to another by direct contact
 e.g. pot of boiling water on a stove, heat transfer from hot element
through conductor(metal pot) into the water
o convection
 heat transfer through a fluid (gas or liquid) by moving circulating
currents
 e.g. Kraft Dinner in a pot, noodles moving and heating up in convective
currents, circulating from hot on bottom to cooler at top of pot
o conductor
 a material that efficiently transfers heat
 e.g. metal
Energy
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ability to do work
measured in joules
o thermal energy
 heat energy
o input/output energy
 input energy = energy that starts a transformation
 output energy = energy that has been transformed
 Isaac Newton’s (1642 — 1727) Law of Energy Conservation states
that during transformations, energy is neither created or destroyed,
it’s changed from one form to another
 starting energy is transformed into another form in order to do work
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 e.g. bodies —> input (food) —>output (work or stored)
potential energy
 stored energy
 becomes kinetic energy
 e.g. bodies are given food, if the energy is not used, it is stored as
potential energy (fat)
kinetic energy
 energy of an object in motion
 e.g. rollercoaster going downwards
hydroelectric energy
 energy created from mining water through a spinning turbine
 water moves downhill and hits a rapidly spinning turbine which is
powered by a crank which converts it to electricity, which comes to a
power station which takes it to our house
mechanical energy
 function of both potential and kinetic energy of moving mechanisms
 e.g. car engine
chemical energy
 energy created by chemical reactions
 e.g. fire or combustion engine
magnetic energy
 energy created by magnetism
 e.g. compass
nuclear energy
 energy created from the nucleus of an atom
 developed by splitting (fission) atoms, usually uranium or plutonium
light energy
 electromagnetic energy released from an energy source in the visible
spectrum
 e.g. incandescent lightbulbs
sound energy
 energy produced by sound vibrations through matter
gravitational energy
 energy of the downward attraction of massive objects such as planets
 e.g. the rotation of the earth around the sun
electrical energy
 energy carried through wire from a generation source
elastic energy (potential)
 energy of elastic materials
 eg. Drum, trampoline