What is the difference between conduction and radiation?

Question

For example heat conducts through solids, but in air/gas it is radiated. How about in liquids, both? Is the only difference the speed?

Convection is very different, though the mention of foil and reflection is part of this. I don't think a vaccuum can allow radiation, as there is nothing to carry a wave. It seems to me that both conduction and radiation occur from one particle to an adjacent. Conduction is electron energy states exciting the adjacent ones, so what about radiation - an escaped particle like an electron?

Answer 1

Homework alert!
Conduction is vibrating atoms/molecules directly jiggling nearby atoms/molecules into vibrating.
Radiation is photons being emitted by one surface (too macroscopic to say atom/molecule) and being absorbed by another.
In summary conduction works through direct contact but radiation is indirect using photons to transfer the energy.
In slightly more confusing sumary conduction=phonons radiation=photons but both can transfer energy.

Answer 2

Speed of the molecules based upon the effect of the degree of heat on the particular material. All materials have different degree points at which they conduct heat, break down to a non-solid, break down to a gas, or combust. All combustion occurs at the gaseous state and depends on the flash-point of the particular gas. As the gases burn off, eventually only carbon is left. Heat is just the by-product of energy. The faster the molecules move, the more energy resulting in more heat.

In electricity, conduction is the movement of electrons in the conductor. When referring to AC, the faster the cycles (frequency) occur, the more chance electrons will escape and be radiated...ie. radio waves. While in the conductor, heat occurs as the amps and voltage increases because this is an increase in energy. This Will also vary with the size and type of conductor.

Added...See:

http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/heatra.html

http://en.wikipedia.org/wiki/Electrical_conductivity

Answer 3

Conduction is the transfer of heat from one solid object to another solid object. Radiation is heat transfer in the form of infrared rays, originating from the sun. Most heat loss in the winter through the attic of a house is from radiation, not conduction or convection. Fiberglass and other insulations will not stop heat loss, it just slows it down. That is what the R factor is, Resistance to heat loss. A very thin layer of aluminum foil blanketed over the insulation will STOP almost 80% of the heat loss and reflect it back down into the living space of a house. If we all used this technique, we would save billions of wasted heating dollars every year. Reflective technology has been used by NASA for many years. Coors beer has a special layer of reflective aluminum with an explanation of it on each bottle of their beer today. E-mail me if you would like more info on reflective technology and saving money heating and cooling.

Answer 4

Heat conduction is the transmission of heat across matter. While, Radiation in physics is a process of emission of energy in the form of waves or particles.

Answer 5

Conduction convection and radiation are the different modes of transfer of energy. conduction happens in all 3 states of matter.
convection in liquids. and radiation in hot bodies.
light is a radiation.

Answer 6

Heat energy traveling through a solid is conduction.
Heat/lght energy traveling through space is radiation - we receive radiation from the sun. It gets absorbed by the Earth and conducted from there.

Answer 7

I'm pretty sure radiation is through gasses only and conduction happens through solids and liquids. Heat radiates from radiators (hence the name) through the air to warm it and im sure its obvious that water is a v-good conductor (think electricity). If im wrong then sorry but im pretty sure thats it

Answer 8

this is it.conduction and radiation are two forms in which heat and travel.depending on conditions provided the show themselves.conduction is quite prominent in material of solids cause it is caused by exchange of vibrational energy while acc. to prevost law every body above absolute zero radiates.infact we always radiate(i.r. radiations).they have diff. equations and diff laws.in liquids convention is more prominent.radiation is observed everywhere.infact the diff is speed coz radiation travels at the speed of light

Answer 9

Condution of heat occurs when direct contact is mede between two substances, if you touch a hot stove, heat is codnucted direcly to your body. Radiation, on the other had, need not have direct contact...we feel the radiation from the sun!!

Answer 10

conduction=bloke stands up with a batton,and the band starts
radiation=you can feel the heat from a radiator