(no subject)
Yeah, but I meant as a physics student, I SHOULD be able to figure this stuff out. As just an intelligent guy, I SHOULD be able to figure this stuff out. ^_^
Heat or cold that moves? For the most part, heat is just energy...kenetic energy (that is, energy of motion.) It's just the molocules having energy so they can shoot around and bump into things, imparting collision energy. Heat can also be radiated, which is...erm...a touch more complicated. Dunno how much anyone that reads this knows about electron energy levels, emitted photons, and the nature of photons (light) as both energy and waves...but essentially, radiation is energy in the form of electromagnetic waves. Light, that is, visibile light, is a narrow band of EM waves. The longest ones, which also have low energy, are radio, next is infrared (IR). Then there's the visible band, ultraviolet (UV), x-rays, and finally gamma rays, the shortest wavelength (very very tiny, like on the scale of protons and electrons), and highest energy. See, long wavelengths have slow frequencies, and low energy. On the flipside, short wavelengths have high requencies, and likewise, high energy. Of course, they all travel at the speed of light for the given medium...but basically...
...need to start a new paragraph, huh? ^_^ Photons can impart energy to things they hit...if they're of a proper frequency. Electrons only have certain stable orbits (corresponding to the number of times they can have an even number of wavelengths...they don't "orbit" in perfect circles, it's more like wavelenghts that close back on themselves to make a stable "orbit"...well, technically that's not correct either, but close enough. ^_^) So when a photon hits an electron, IF it's the right amount for the electron to go to a higher STABLE orbit, than the electron absorbs it, its energy increases, and it moves to a higher orbit. This means the atom as a whole has more energy, and more energy, means more heat. Of course, electrons like being in lower energy states, so usually they'll send out the energy in the form of another photon (or of crossing several energy levels, some combination of photons as it drops down one level at a time.)
The two main ways that heat is transfered from your body is radiation and conduction. Radiation is giving energy without having to touch something, like using photons/EM waves. ConDUCTION is transfering by directly touching (the molocules coliding and the one with less energy taking some energy from the one with more.) To oversimplfy things, heat is infrared energy waves. In fact, humans are radiating the stuff all the time. If our eyes could detect IR, you'd be able to see people in the dark, essentially, which is how IR goggles work too. ^_^ But see, other forms of EM radiation also carry energy. E = h f where f is the frequency and h is a constant...the guy it's named after's name eludes me at the moment, but that's just cause it's 12:40 AM. ^_^ Not Bohr though. ^_^ Plank! Plank's constant. Knew I knew it. ^_^
But yeah, higher frequency gives higher energy, and IR is lower energy than visible light, though also higher energy than radio waves, which only would affect high orbit number atoms anyways.
But yeah, it's heat that moves between things, from hotter thing to cooler. One of the laws of Thermodynamics describes it, either the first or zeroeth, don't remember which. It's just a common thing in nature and natural processes though, things move from higher to lower energy, pressure, whatever.
...now, on the other hand, you have the "hot air rises, cool air falls" thing. What that is is a matter of density and beuancy...boyancy...whatever. See, hot stuff has higher energy, right? And higher energy means molocules are zipping around faster. Since they're moving faster, they're also more dispersed and spread further apart. This means that for any given volume of the same type of thing, hotter stuff is less dense, which ALSO means it weighs less. This is where boyancy(sp?) comes in. Usually we only think of things being boyant in terms of water, but it works for anything that's not solid whose molocules can move around, including air. Basically, think of it this way. You have a block of air with higher density (more weight) because it's hotter, and another block of lower density (less weight) because it's cooler and doesn't have as much energy. Gravity pulls both down, but because the one with less density is less massive (mass = density/volume), than the force of gravity (F_g = G*m_1*m_2 / d^2 where G is a constant, the m's are the mass of the Earth and the thing it's pulling on, and d is the distance between the centers of mass of the two things pulling on each other...remember, they're pulling on each other, we pull on the Earth as much as it pulls on us, it's just a lot bigger so it doesn't really notice. ^_^ It's like when a fly bumps you, it can't really hope to move you just cause you're so much more massive and F = ma, remember? ^_^ Larger masses are harder to accelerate, inertia and all that.)
So...the more dense, heavier, colder thing will "sink" while the less dense, ligher, hotter thing will "float" upward, provided it doesn't get rapped by something (like how air pockets work in underwater caves and such. They'd LIKE to rise out, but they're stuck by the cave/rock.
In any case, that's the difference. HEAT travels from hotter to colder thing, but if you have things of different temperature, the hotter one is lighter and will "float" up as the colder, heavier stuff "sinks".
Of course, the atmosphere doesn't totally work this way, the reason being that you have different types of stuff in the different atmospheric layers. Oxygen is heavier than Helium at the same temperature, for instance, which means even if they have the same densities, Helium will float upward. This also means that Helium can be colder and still float above Oxygen. As a consequence, our atmosphere has some odd temperature changes. First it gets cooler, than it gets warmer, and so on, and this is because that different layers have different makeups, as well as that the far upper layers also catch more of the sun's radiation. In fact, the upper atmosphere catches a lot of the more harmful types of radiation, x rays, gamma rays, and most of the UV rays that the sun sends. It also catches some lower band IR waves and raido waves after a certain point...although radio, IR, and visible aren't really harmful to humans at all. Some people say we evolved to see visible because it's what all gets through our atmosphere...but then I have a problem with this line of reasoning as I'd think we'd also see IR, both because that at least upper or "near" IR also gets through our atmosphere as well as is emitted by animals and humans. Seems being able to see that kinda light would also be evolutionarily useful, yet we don't see it. But some people will believe anything, I guess... ^_^;
Let's see...so did I totally tell you more than you ever wanted to know about energy, light, heat, and air motions? ^_^
...the funny thing is, all the time I think I don't know much because of how hard my classes seem and how I don't ever seem to know all the stuff that I "need" to know for tests and stuff, but the thing is, I also seem to be able to answer a LOT of questions people ask me, and with more details than they really want to know. ^_^ But knowledge alone isn't power...
Oh, I guess to answer your question, both move. Cold goes down cause it's heavier, and hot goes up because essentially cold shoves it out of the way...which is also how boyancy works in everything (including water.) But as far as the energy flow, energy goes from more energetic things to less energetic things. So there ya go.
Heat or cold that moves? For the most part, heat is just energy...kenetic energy (that is, energy of motion.) It's just the molocules having energy so they can shoot around and bump into things, imparting collision energy. Heat can also be radiated, which is...erm...a touch more complicated. Dunno how much anyone that reads this knows about electron energy levels, emitted photons, and the nature of photons (light) as both energy and waves...but essentially, radiation is energy in the form of electromagnetic waves. Light, that is, visibile light, is a narrow band of EM waves. The longest ones, which also have low energy, are radio, next is infrared (IR). Then there's the visible band, ultraviolet (UV), x-rays, and finally gamma rays, the shortest wavelength (very very tiny, like on the scale of protons and electrons), and highest energy. See, long wavelengths have slow frequencies, and low energy. On the flipside, short wavelengths have high requencies, and likewise, high energy. Of course, they all travel at the speed of light for the given medium...but basically...
...need to start a new paragraph, huh? ^_^ Photons can impart energy to things they hit...if they're of a proper frequency. Electrons only have certain stable orbits (corresponding to the number of times they can have an even number of wavelengths...they don't "orbit" in perfect circles, it's more like wavelenghts that close back on themselves to make a stable "orbit"...well, technically that's not correct either, but close enough. ^_^) So when a photon hits an electron, IF it's the right amount for the electron to go to a higher STABLE orbit, than the electron absorbs it, its energy increases, and it moves to a higher orbit. This means the atom as a whole has more energy, and more energy, means more heat. Of course, electrons like being in lower energy states, so usually they'll send out the energy in the form of another photon (or of crossing several energy levels, some combination of photons as it drops down one level at a time.)
The two main ways that heat is transfered from your body is radiation and conduction. Radiation is giving energy without having to touch something, like using photons/EM waves. ConDUCTION is transfering by directly touching (the molocules coliding and the one with less energy taking some energy from the one with more.) To oversimplfy things, heat is infrared energy waves. In fact, humans are radiating the stuff all the time. If our eyes could detect IR, you'd be able to see people in the dark, essentially, which is how IR goggles work too. ^_^ But see, other forms of EM radiation also carry energy. E = h f where f is the frequency and h is a constant...the guy it's named after's name eludes me at the moment, but that's just cause it's 12:40 AM. ^_^ Not Bohr though. ^_^ Plank! Plank's constant. Knew I knew it. ^_^
But yeah, higher frequency gives higher energy, and IR is lower energy than visible light, though also higher energy than radio waves, which only would affect high orbit number atoms anyways.
But yeah, it's heat that moves between things, from hotter thing to cooler. One of the laws of Thermodynamics describes it, either the first or zeroeth, don't remember which. It's just a common thing in nature and natural processes though, things move from higher to lower energy, pressure, whatever.
...now, on the other hand, you have the "hot air rises, cool air falls" thing. What that is is a matter of density and beuancy...boyancy...whatever. See, hot stuff has higher energy, right? And higher energy means molocules are zipping around faster. Since they're moving faster, they're also more dispersed and spread further apart. This means that for any given volume of the same type of thing, hotter stuff is less dense, which ALSO means it weighs less. This is where boyancy(sp?) comes in. Usually we only think of things being boyant in terms of water, but it works for anything that's not solid whose molocules can move around, including air. Basically, think of it this way. You have a block of air with higher density (more weight) because it's hotter, and another block of lower density (less weight) because it's cooler and doesn't have as much energy. Gravity pulls both down, but because the one with less density is less massive (mass = density/volume), than the force of gravity (F_g = G*m_1*m_2 / d^2 where G is a constant, the m's are the mass of the Earth and the thing it's pulling on, and d is the distance between the centers of mass of the two things pulling on each other...remember, they're pulling on each other, we pull on the Earth as much as it pulls on us, it's just a lot bigger so it doesn't really notice. ^_^ It's like when a fly bumps you, it can't really hope to move you just cause you're so much more massive and F = ma, remember? ^_^ Larger masses are harder to accelerate, inertia and all that.)
So...the more dense, heavier, colder thing will "sink" while the less dense, ligher, hotter thing will "float" upward, provided it doesn't get rapped by something (like how air pockets work in underwater caves and such. They'd LIKE to rise out, but they're stuck by the cave/rock.
In any case, that's the difference. HEAT travels from hotter to colder thing, but if you have things of different temperature, the hotter one is lighter and will "float" up as the colder, heavier stuff "sinks".
Of course, the atmosphere doesn't totally work this way, the reason being that you have different types of stuff in the different atmospheric layers. Oxygen is heavier than Helium at the same temperature, for instance, which means even if they have the same densities, Helium will float upward. This also means that Helium can be colder and still float above Oxygen. As a consequence, our atmosphere has some odd temperature changes. First it gets cooler, than it gets warmer, and so on, and this is because that different layers have different makeups, as well as that the far upper layers also catch more of the sun's radiation. In fact, the upper atmosphere catches a lot of the more harmful types of radiation, x rays, gamma rays, and most of the UV rays that the sun sends. It also catches some lower band IR waves and raido waves after a certain point...although radio, IR, and visible aren't really harmful to humans at all. Some people say we evolved to see visible because it's what all gets through our atmosphere...but then I have a problem with this line of reasoning as I'd think we'd also see IR, both because that at least upper or "near" IR also gets through our atmosphere as well as is emitted by animals and humans. Seems being able to see that kinda light would also be evolutionarily useful, yet we don't see it. But some people will believe anything, I guess... ^_^;
Let's see...so did I totally tell you more than you ever wanted to know about energy, light, heat, and air motions? ^_^
...the funny thing is, all the time I think I don't know much because of how hard my classes seem and how I don't ever seem to know all the stuff that I "need" to know for tests and stuff, but the thing is, I also seem to be able to answer a LOT of questions people ask me, and with more details than they really want to know. ^_^ But knowledge alone isn't power...
Oh, I guess to answer your question, both move. Cold goes down cause it's heavier, and hot goes up because essentially cold shoves it out of the way...which is also how boyancy works in everything (including water.) But as far as the energy flow, energy goes from more energetic things to less energetic things. So there ya go.