So that is definitely happening when we look at a fire like this, that neighboring molecules are bumping into other molecules and transferring energy. Things with higher kinetic energy are bumping into things with lower kinetic energy and transferring some of that kinetic energy and they're transferring some of that momentum. And we have a whole video on thermal conduction, but that's what's happening. And then they're going to bump into other molecules that might not have quite as high kinetic energy, but then they're going to transfer that kinetic energy through these collisions.

And so the ones that just combusted, or the molecules right near the reaction, or maybe the ones that were part of the reaction, they're gonna have this really high, they're gonna have this really high average kinetic energy 'cause all of this energy was released from that combustion reaction.

And remember, temperature is proportional to average kinetic energy. And that energy is going to excite the molecules that are around it, so you have these molecules, you have these molecules that end up getting a lot of kinetic energy. But you're taking carbon molecules and their bonds and then in the presence of oxygen and some heat you have a combustion reaction producing carbon dioxide and producing water and even more energy than you put into it, so it's producing a lot of energy. So what is the conduction going on? Well what we have going on in the fuel for our fire, so down here the fuel for our fire we have our classic combustion reaction and I encourage you to watch the video on that in our chemistry playlist, or chemistry section if you're interested in it. And I could say thermal conduction, thermal convection, and thermal radiation, and the word thermal is just relating to things dealing with temperature. So I'll do this, thermal, thermal radiation, thermal radiation. We're observing conduction, conduction, convection, convection, convection, and thermal radiation all at the same time. When we observe what we call fire we have this combustion reaction going on and then we see these flames what we're really observing are the three forms of thermal energy transfer. (Well, unless you are directly ABOVE the fire, but then you are in big trouble. Convection will take the heat straight up, and there is no way the fire's heat can reach you by conduction outdoors since the volume of air is so enormous and any air that does get warm will rise. Another way to be almost certain that it is radiation is if you suddenly block the direct path from the fire to your face with something (a piece of paper or even your hands), and you immediately feel a big difference in how warm your face feels, it is radiation.įinally, if you are sitting near a fire OUTDOORS, then the warmth you feel has certainly got to be radiation.

Did the fire just heat up all the air in the room (conduction), did it heat some air that flowed over to you due to drafts or currents (convection), or is the heat reaching you in the form of infrared waves (radiation)? One way to know that it is almost surely radiation is if the side of you facing the fire feels much warmer than the side of you facing away from the fire. Sometimes it can be difficult to know whether the heat you feel is due to conduction, convection, or radiation.

Electromagnetic radiant energy examples