![]() (It can of course loose it via radiation.) Unlike radiation, if there is no medium near the source, it cannot loose its heat simply using convection. So, its clear that convection requires a medium (specifically, a non-solid medium). This process continues, and eventually every molecule of water gets heated up.Īs you can see, in this process, the motion of the particles lead to the heating of the whole body (water, in this case) - the warmer ones moved away from the source of heat to let the cooler ones collect the heat. Now, again it gets heated up, and moves up when it becomes lighter than the (previously heated) water on the top, but this time getting more heated that the water on the top. Now the (relatively) cooler region of water on the top comes down and begins to heat up. The water in the lower region gets heated up, becomes lighter in weight, and hence comes to the top. ![]() I will try explaining convection using a simple example.Ĭonsider a beaker of water being heated from the bottom. Now, since this heat energy travels in the form of waves, it does not necessarily require any medium to travel. (So, even we radiate!) Of course, the amount of this radiation depends on the temperature, so the more the temperature of the body, the more heat it gives out. ![]() radiates) some heat in the form of waves. convection = molecules heated like in conduction, but then move to another locationĮvery body which has a temperature above 0 Kelvin gives out (ie.conduction = molecules exciting their neighbors successively.radiation = generated and absorbed photons.In convection, the molecules of gas near the object gain energy, like in the conduction case, but those same molecules that gained energy then travel through the environment to some other location where they then give off their heat energy. Over time, the heat "travels" through the object. As each atom gains energy from its more energetic neighbors, so it gives up energy to its less energetic ones. The individual atoms in the object are vibrating with heat energy. In conduction, the next simplest example, there is no generation of photons (physics nerds forgive me for the sake of simplicity). This is how infrared goggles work and they would work equally well in high vacuum as here on earth. If that energy is deposited on your retina or a CCD (like in a digital camera), an image forms over time. These photons leave the iron, pass through the environment, and eventually collide with some other object where they are absorbed and deposit their energy. The creation of these photons takes energy energy from the heat of the iron. On a molecular level, the material is emitting lots and lots of photons (hence why it is glowing red). Unfortunately, analogies are hard but if you can visualize the particles involved, it would help. Conduction also requires a medium, but, again, it is a fundamentally different mechanism than either convection or radiation in this case it is the transfer of energy through a medium. Convection is the transfer of energy by movement of a medium, whereas radiation is the transfer of energy by, well, thermal radiation. That convection requires a medium is not the main difference, it is simply the most obvious aspect of what is a fundamentally different mechanism for transferring energy. To pretty much everything you stated in your question, "no".
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