The internet will tell you that heat is energy in motion. When you take the temperature of a substance, are you measuring the approximate amount of heat energy per particle of that substance? The total heat energy of that substance would be the temperature multiplied by number of particles, correct? And the total energy of that substance would be the temperature multiplied by the pressure multiplied by the number of particles, correct?
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Everything you said makes sense except:
>And the total energy of that substance would be the temperature multiplied by the pressure multiplied by the number of particles, correct?
The "total energy of the substance" is ill-defined. You can talk about heat energy, chemical energy, nuclear energy, mass-energy equivalence energy etc. So the idea doesn't really have a meaning outside of given specific contexts.
You can basically figure out what the pressure of a gas is if you know the volume, number of particles, and the temperature through the ideal gas law. Heat energy is basically kinetic energy. The more heat a material has, the more the particles will move around, but pressure inhibits the movement of particles, but increasing the pressure of a substance also increases the temperature.
The gas laws yes. But OP said substance. The total energy in a stick of gum for example, is more nebulous.
I'm OP, and I also made that post. So is there no concept of total energy? If not, why?
Say you swallow a blade of grass. You, as a human, can't digest the cellulose, so that part of the chemical potential energy in the grass is inaccessible to you. If a cow swallowed that blade of grass instead, it would be able to obtain that chemical energy via digesting the cellulose bonds. Matter, in the form of atoms and molecules, is simply slowly-moving energy. Once the cow excretes out the grass, you have cow waste right. But you can further burn that to extract even more chemical energy. You then only have ash remaining. But you could put that ash into a star to extract nuclear energy out of it. Once it fuses to iron you could then react that iron with antimatter iron and convert it into light. The idea of total energy isn't well defined. It makes more sense to talk about the amount of energy gained or lost via some specific process.
>The idea of total energy isn't well defined. It makes more sense to talk about the amount of energy gained or lost via some specific process.
Thanks, anon. This should've been at the beginning of your post. Energy is the result of different processes, and you can use different processes in series to extract even more energy from an original substance.
It's like how heat engines extract energy across a thermal gradient. If both sides of the engine are the same temperature, then the engine would cease functioning, even if both sides are "hot"
Similarly, you could say a pebble on the ground has 0 gravitational potential energy, but if you dig a 10 foot hole and calculate based on the bottom of the hole, you can now say it has gravitational potential energy. Dropping the pebble into the hole would cause this potential energy to be converted into kinetic energy as it falls.
Me and you, on Earth, have a lot of gravitational potential energy relative to the Sun; we could theoretically fall into the Sun and gain a massive amount of speed as we did so. but we are on Earth in a stable orbit so it doesn't enter into practical calculations.
Thanks for the information, anon.
exactly
if you were to calculate the actual energy occupied by said "matter" in the underlying quantum field it's a wave in, well...
>In cosmology, the cosmological constant problem or vacuum catastrophe is the disagreement between the observed values of vacuum energy density (the small value of the cosmological constant) and theoretical large value of zero-point energy suggested by quantum field theory.
>Depending on the Planck energy cutoff and other factors, the discrepancy is as high as 120 orders of magnitude, a state of affairs described by physicists as "the largest discrepancy between theory and experiment in all of science" and "the worst theoretical prediction in the history of physics".
You mean like the average kinetic energy of one particle multiplied by the number of particles?
Why don't you read a basic statistical mechanics textbook?
Why does heat cause quark - antiquark condensate to get destroyed?
If heat is molecular movement then I don't see how you heat up a void of nothing but virtual particles and condensates so much that the condensates vaporize and you get a more empty void (which then almost immediately births new quark antiquark pairs). What the frick is moving in this case?
I get that the gold nuclei were moving really fast, but there were only a few and they exploded and made heat, but it the only particles in a vacuum explode then wtf is the heat moving?
Heat isn't the movements of matter, it's just something that correlates closely with that and a better definition hasn't come forward yet.
I have wondered this for a long time. In particle accelerators, you have two particles accelerated into one another. That's it, nothing else to vibrate. But then we'll talk of the resulting heat being "a billion times hotter than the sun." What is hot? All the parts of the various protons, neutrons, and electrons that blew up? What is storing said energy?
Space itself? All the virtual particles in space (the frick is up with creation out of nothing too)? All these condensates, shit from the Big Bang that fills space but that we cannot see easily?
How can empty or emptier space be higher energy than space filled with chiral condensate and so the shit gets brought into existence from "nothing?" What carries this nothing energy? Because a symmetry is broken shit just becomes?
If, as articles tell me, I'm being mislead in my thinking because space doesn't exist and quarks aren't located in space and don't have size, then what the frick is getting emptier or less empty in these experiments? Are there any candidates for replacing space-time if so many people think it is broken?
Isn't it a little weird that we just keep applying fixes to the Standard Model and inventing particles that fix it and then find them, but then other models also sometimes find their shit?
I'm no expert but it sounds like we could observe things that fit the solutions for equations and still be conceptually very far off, which is why things become increasingly more complex and multifaceted, not simpler as you'd think unification would work. Seems somewhat like the Ptolemaic system's epicycles where shit just got more and more complex, entities kept multiplying, math was fixed which in turn led to "verification" by observations, but really the whole model is wrong and what causes the complications.
>But then we'll talk of the resulting heat being "a billion times hotter than the sun."
You would not hear this from one particle physicist to another. However, you could say that processes are possible in these colliders that are not possible in the Sun at a given temperature. I chose to ignore 95% of your post though, since it sounds like what I wrote when I smoked weed for the first time.
How so? I've read two books by Nobel laureates who talk about the extreme heat of these reactions. Given they seem to take pains to be precise, why are they calling this heat when it isn't heat?
Popsci books? Like you said, heat is not well-defined in that case. But heat is something people have more of a feeling about than center-of-mass energy. Rule of thumb: At 30°C, each molecule has about 40 meV of kinetic energy. In LHC, each proton has about 7 TeV of energy. If you work in particle physics, the temperature associated with 7 TeV doesn't interest you at all. On the other hand, laypeople know what temperature is, but not what 40 meV or 7 TeV are. That's why it's "translated" even though it doesn't make much sense, like you correctly said.
What I always tell my students. Use units, then you'll spot mistakes :^)
I use units whenever I go over practice problems on Khan Academy to make sure my answer is correct.
How fast does an ice cube need to travel to have the same energy as a boiling pot of water with the same volume as the ice cube? Can someone calculate this?
IQfy thinks my post is spam for some reason.
Just from my gut feeling there must be some big mistake here. If you drop an ice cube from a height that is enough to accelerate it to 1.73 m/s, then it doesn't melt and boil on impact.
Where des your mass come from? The 1,048.... (I can't post the number or IQfy thinks it's spam) Or what's that supposed to be? For the love of god, use units, man.
>If you drop an ice cube from a height that is enough to accelerate it to 1.73 m/s, then it doesn't melt and boil on impact.
The combined heat and kinetic energy of the ice cube becomes equivalent to the combined heat and kinetic energy of the pot of boiling water, which is not in motion, and hence, has no kinetic energy, so the heat plus kinetic energy of the ice cube becomes equivalent to the heat energy of the pot of boiling water.
>The combined heat and kinetic energy of the ice cube becomes equivalent to the combined heat and kinetic energy of the pot of boiling water, which is not in motion, and hence, has no kinetic energy, so the heat plus kinetic energy of the ice cube becomes equivalent to the heat energy of the pot of boiling water.
Still doesn't make sense. The ice cube has no kinetic energy after the impact.
Then you are using the formula wrong. Use units and you'll see that you did a huge mistake.
Let me use 1kg and not the "same volume" bullshit, it's a small difference to the thing the other anon asked, but I don't care
[eqn]
begin{align}
Delta E_mathrm{th} &= c , m, Delta T\
&= 4.2 frac{mathrm{kJ}}{mathrm{kg,K}}cdot 1,mathrm{kg}cdot 100,mathrm{K}\
& = 420,mathrm{kJ}\
E_mathrm{melting} &= 334,frac{mathrm{kJ}}{mathrm{kg}}cdot1,mathrm{kg} = 334,mathrm{kJ}\
E_{mathrm{ice rightarrow boiling water}} &=753,mathrm{kJ}\
E_mathrm{kin} &= 1/2, m,v^2 stackrel{!}{=} 753,mathrm{kJ}\
v &= sqrt{2cdot 753,mathrm{kJ} / 1,mathrm{kg}}\
&= sqrt{1506000,mathrm{m}^2/mathrm{s}^2}\
&= 1277,mathrm{m}/mathrm{s}
end{align}
[/eqn]
Does that mean if the ice cube is traveling at 1000m/s and impacts something it will instantly melt and boil?
>The 1,048
That's the exact value I got from approximating the number of joules of kinetic energy in the ice cube, but I rounded it to 1,050,000, since the calculation for it involved a value with only three significant digits, it's mass of 0.917kg.
I made a massive mistake by putting heat energy where only mass should've been.
I was thinking 1.3 m/s is way too slow. That implies you could boil the icecube by throwing it at a wall.
The ice cube would only generate heat through friction with air. It would remain an ice cube in space. My calculation was to find how much heat plus kinetic energy the ice cube would need to equal the heat energy of the pot of boiling water.
mass increases with heat
wat
It will also lose energy by deforming whatever it hits. Also, you need to accelerate it without heating. Note that we're talking mach 3 here.
Baby don't burn me.
Don't burn me no more