# The Naked Scientists Forum

### Author Topic: Why when things are heated they become lighter?  (Read 9190 times)

#### greeniemax

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##### Why when things are heated they become lighter?
« on: 05/03/2012 09:13:33 »
Before you answer please read below, I know that when any gas is heated the density for it changes, the density get lower that means area it occupies gets more and because of its density it gets lighter and goes upward.

Great but problem is why less dense objects are lighter? For instance...

E=MC2 so M=E/C2

Thus more energy you increase (by heating something) more massive it gets, if its more massive than it should have more gravitational pull because matter with higher mass have more gravitational pull, but it doesn't work.

Why? Why higher energy object have less gravitational pull if we consider gravitational pull is directly proportional to mass than it would mean heating something would make it less massive? Does it mean higher energy level electrons are less massive?

Or does it mean energy and matter are not proportional?

#### wolfekeeper

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##### Re: Why when things are heated they become lighter?
« Reply #1 on: 05/03/2012 17:04:20 »
To an excellent approximation, heating something doesn't make it lighter or heavier at all.

In relativity theory, heating something gives an absolutely miniscule increase.

The reason why hot air balloons rise is because of buoyancy; the balloon displaces denser air when you heat it up, which makes it rise, in much the same way boats float on the ocean (the exact reason it rises is that the density of the hot air is lower than the air around it-it has a lower 'head', and that difference in weight pushes the balloon upwards).

It's nothing to do with things being lighter or heavier, only less or more dense.
« Last Edit: 05/03/2012 17:16:28 by wolfekeeper »

#### greeniemax

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##### Re: Why when things are heated they become lighter?
« Reply #2 on: 06/03/2012 09:45:34 »

But that is what I said above, that isn't a problem but we automatically assume that less dense things will rise but we have no real reason behind it, we just assume it to be there.

Hot gas rise on earth or a planet that has gravity but not if we are in 0 gravity, because there is no rise. In 0 gravity less dense object mix with higher density objects without any problem, air bubble that is heated and has less density mixes perfectly fine with air around it and it doesn't go up or down.

In case there is no gravity, the expansion of the produced gases does not cause them to go anywhere. They just stand there and expand spherically around the source. So we have neither of the two effects above. The flame does not point anywhere, and burns like a sphere (given the reaction point is small, like a match). Second, since the auto-oxygen-feeder mechanism also fails, the flame burns in rather dull colors, and will extinguish itself rather quickly if there is no flow of air (or if the match is not moved around) to feed oxygen into the reaction.

That means gravity plays part in things rising, that would mean that anything with higher energy level rises because it doesn't have the same attraction toward the object.

As I said in my anomaly example, gravity formula could be in such a way

g=m1+e1+m2-e2

Remember that m1 and e1 are for larger object, while m2 and e2 are for smaller object (as I'm not a mathematician I really have to work hard on making a formula that works for both). I'm not saying it would make a lots of difference but there is a visible effect of this problem, in gravity anomaly that we get from GRACE and in the density problem.

My prediction is in 0G energy would have a repelling property, because if you make m1 and e1 as 0 that is what you get.

I really hope to get more responses on it, I really want people to help me with this by giving me example and proving me wrong so in case I'm wrong I would know.

Thanks

#### imatfaal

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##### Re: Why when things are heated they become lighter?
« Reply #3 on: 06/03/2012 11:06:25 »

But that is what I said above, that isn't a problem but we automatically assume that less dense things will rise but we have no real reason behind it, we just assume it to be there.
No - it rises to allow the system to reach the most stable energy state .  There is stored potential in a heavy thing lifted above the ground, there is less when the heavy thing is on the ground and a light thing is in its place.

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Hot gas rise on earth or a planet that has gravity but not if we are in 0 gravity, because there is no rise. In 0 gravity less dense object mix with higher density objects without any problem, air bubble that is heated and has less density mixes perfectly fine with air around it and it doesn't go up or down.
A volume of hot gas will mix as well as lift even in a gravitational field

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That means gravity plays part in things rising, that would mean that anything with higher energy level rises because it doesn't have the same attraction toward the object.
- First part yes, second part - why.

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As I said in my anomaly example, gravity formula could be in such a way

g=m1+e1+m2-e2
Dimensional Analysis would be good here

ms^-2 DoesNotEqual kg + joules

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Remember that m1 and e1 are for larger object, while m2 and e2 are for smaller object (as I'm not a mathematician I really have to work hard on making a formula that works for both). I'm not saying it would make a lots of difference but there is a visible effect of this problem, in gravity anomaly that we get from GRACE and in the density problem.

My prediction is in 0G energy would have a repelling property, because if you make m1 and e1 as 0 that is what you get.
actually energy is the basis of all gravity - and will have an attractive property.  General relativity calculates the curvature of spacetime through (very vaguely) the amount of mass and energy and their fluxes - and to cut to the chase the more energy the more gravity the greater the attraction

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I really hope to get more responses on it, I really want people to help me with this by giving me example and proving me wrong so in case I'm wrong I would know. Thanks
Not sure what I can say apart from the fact that your ideas that energy is repulsive and matter attractive are completely contradicted by our best model of gravity ie General Relativity.

#### wolfekeeper

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##### Re: Why when things are heated they become lighter?
« Reply #4 on: 06/03/2012 11:58:30 »
But that is what I said above, that isn't a problem but we automatically assume that less dense things will rise but we have no real reason behind it, we just assume it to be there.
No, I know exactly why, it's because it weighs less than the AIR IT DISPLACES.

When you heat up a (we'll assume for the moment for clarity that it's a sealed-type) hot air balloon, it gets physically bigger, but weighs the same.

So if it was balanced before, it now weighs less than the air it displaces.

You know like water has head? Like if you have a pipe 10 feet in the air, it has 10 ft of head? Well air is a fluid too, and it too has 10 feet of head- it's just that 10 feet head of air is a lot less pressure than 10 feet of water so you don't notice it so much.

But if you have the head of air between the top of the balloon and the bottom, around the outside of the balloon, then that pressure pushes the balloon upwards all the time, under all circumstances; you've got a slight buoyancy from the air right now on you too! But if the weight of the balloon is less than that pressure acting over the bottom of the balloon then there's a net force upwards.

It's the same with ships and submarines in water. It's nothing to do with the heat per se, it's just to do with weight per unit volume. It turns out that that's the same as saying that if the balloon weighs less than air it displaces, if you  do the maths, then balloon floats on air; it's forced up by the head.
« Last Edit: 06/03/2012 12:03:52 by wolfekeeper »

#### greeniemax

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##### Re: Why when things are heated they become lighter?
« Reply #5 on: 06/03/2012 16:09:14 »
Hi imatfaal,

If gravity plays a part in rising and sinking of objects when energy levels for these objects change that means the things aren't going away from gravity just because they are less dense, because same results can't be duplicated when you are in zero gravity. In normal gravity these different energy level objects (for ease lets imagine air), the object with lesser energy level (cold air) will go down, while warm air (higher energy) would rise. While in 0G there is no up or down and higher energy object can't go above the lower energy object.

Now we have no reason what so ever to say "Why certain thing to up when they are less dense?", we take it for the way it exists, but it doesn't work when we are in zero gravity it only works when we have gravity on one side. Now we could say whatever is needed but looking into the matter it is one fact that objects with higher energy level tend to rise away from gravity or move away from gravity. You may imply that hot iron rod has more energy than hydrogen at 0 Deg C but that isn't entirely true because hydrogen has internal energy that would be more than energy in rod, this is why its in gas form even at 0 deg C.

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A volume of hot gas will mix as well as lift even in a gravitational field
Yes they do but that is part of equilibrium of energy but any higher energy object will rise, but in zero gravity it would not go up.

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Dimensional Analysis would be good here

ms^-2 DoesNotEqual kg + joules

I'm working on it, right now I'm working on something else I call it charge time and once I finish that I'll go ahead and work on the math for this.

I totally agree my idea sounds stupid, I know but two major things are answered from it, gravity anomaly and things moving away from gravity when they have more energy than its surroundings.

Hi Wolfekeeper,

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When you heat up a (we'll assume for the moment for clarity that it's a sealed-type) hot air balloon, it gets physically bigger, but weighs the same.

Weight is gravitational pull on certain object, the weight would not be same because if you tie it to a weighing machine it would give negative weight even though volume is more but because of the upward thrust it will not give you any weight. So even for same amount of material the weight actually changes, x atoms of O, will actually weigh less if you put them in confined area.

Yes but if you put that in a total vacuum they wouldn't rise because they have nothing to rise against, there is no difference in energy and it doesn't matter how much that matter is heated the weight will not change much.

hmm... that means there is a flaw...

back to drawing board for me... I have to find how much if any the weigh changes in a vacuum.

#### greeniemax

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##### Re: Why when things are heated they become lighter?
« Reply #6 on: 07/03/2012 08:13:04 »
Okay after doing some searching on the internet, its clear that higher energy objects are lighter than lower energy objects.

Thus gravity doesn't make sense as attraction between two masses but mass and energy.

In case the energy is increased equilibrium forces the atom away so that lesser energy atom could take the same space and increase the amount of energy.

Thus my assumption of energy and matter being source of attraction is right.

#### MikeS

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##### Re: Why when things are heated they become lighter?
« Reply #7 on: 07/03/2012 09:26:22 »
Clip

Not sure what I can say apart from the fact that your ideas that energy is repulsive and matter attractive are completely contradicted by our best model of gravity ie General Relativity.

Energy is subject to entropy and one way of accomplishing that is by dispersal.

Matter is subject to gravity and also subject to entropy but accomplishes this in the opposite way by matter combining.

It is true that according to GR energy has gravity but I believe its dispersal tenancies far outweigh any gravitational attraction that it may possess.  A hot air balloon is an example of this.
« Last Edit: 07/03/2012 09:29:08 by MikeS »

#### imatfaal

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##### Re: Why when things are heated they become lighter?
« Reply #8 on: 07/03/2012 12:41:19 »
Okay after doing some searching on the internet, its clear that higher energy objects are lighter than lower energy objects.
Links?  I can tell you that if you drop a ball the same time as you fire one horizontally  with a bowling (pitching for USAnians) machine that they will hit the floor at the same time

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Thus gravity doesn't make sense as attraction between two masses but mass and energy.
Regardless of sense - we are dealing in models that comply and predict reality, not conform with your credulity.

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In case the energy is increased equilibrium forces the atom away so that lesser energy atom could take the same space and increase the amount of energy.

Thus my assumption of energy and matter being source of attraction is right.
GIGO - unfo.

#### imatfaal

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##### Re: Why when things are heated they become lighter?
« Reply #9 on: 07/03/2012 12:44:46 »
Clip

Not sure what I can say apart from the fact that your ideas that energy is repulsive and matter attractive are completely contradicted by our best model of gravity ie General Relativity.

Energy is subject to entropy and one way of accomplishing that is by dispersal.

Matter is subject to gravity and also subject to entropy but accomplishes this in the opposite way by matter combining.

It is true that according to GR energy has gravity but I believe its dispersal tenancies far outweigh any gravitational attraction that it may possess.  A hot air balloon is an example of this.
This is just wrong.  a hot air balloon works because hot air rises; ie because the volume of gases interior to the balloon have a smaller mass than a similar volume of normal atmosphere

#### MikeS

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##### Re: Why when things are heated they become lighter?
« Reply #10 on: 08/03/2012 06:52:38 »
Clip

Not sure what I can say apart from the fact that your ideas that energy is repulsive and matter attractive are completely contradicted by our best model of gravity ie General Relativity.

Energy is subject to entropy and one way of accomplishing that is by dispersal.

Matter is subject to gravity and also subject to entropy but accomplishes this in the opposite way by matter combining.

It is true that according to GR energy has gravity but I believe its dispersal tenancies far outweigh any gravitational attraction that it may possess.  A hot air balloon is an example of this.
This is just wrong.  a hot air balloon works because hot air rises; ie because the volume of gases interior to the balloon have a smaller mass than a similar volume of normal atmosphere

No it's not wrong.

"A hot air balloon works because hot air rises; ie because the volume of gases interior to the balloon have a smaller mass than a similar volume of normal atmosphere "

That is true because the heated molecules of gas vibrate with more energy and (attempt to disperse) take up more space than they would if cold.  As I said "Energy is subject to entropy and one way of accomplishing that is by dispersal."  This effect is greater than the energies gravitational attraction as I said "It is true that according to GR energy has gravity but I believe its dispersal tenancies far outweigh any gravitational attraction that it may possess."
« Last Edit: 08/03/2012 08:13:40 by MikeS »

#### greeniemax

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##### Re: Why when things are heated they become lighter?
« Reply #11 on: 11/03/2012 10:40:31 »
MikeS thanks for your great response but just for a second think why it doesn't work in absence of gravity.

In Zero Gravity the hot air balloon (in air inside the space station) wouldn't move up or down or anywhere, that means gravity has something to do with it, this phenomenon only works when gravity is applied to the problem.

Thus you could simply say that increase in gravity in a smaller body would decrease the attraction, while increase in energy on a larger object (body) would have increase in attraction, you could try to find 100 different ways to tell yourself that fine it doesn't work in Zero gravity because of such and such reason but it bounces to a single issue that we have a set of rules that we live by, maybe we don't care or know what is the cause of these rules.

I'm just throwing out their my assumption because if you look at it, it does solve the problem of earth surface gravity anomalies and answers for the time being. Maybe I'm wrong and the whole idea is bad but its an idea that gives a solution to our understanding.

Thus lower density objects are higher energy objects and higher density objects are low energy, it doesn't matter what is talked about.

#### greeniemax

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##### Re: Why when things are heated they become lighter?
« Reply #12 on: 11/03/2012 10:59:01 »
imatfaal a hot ball will drop slower than a cold ball anyways.

Hot ball will expand and thus will have more friction compared to a colder ball, so basically you can't test the idea with hot a cold balls.

In case you want to test it with small material in a total vacuum and that material is heated by laser, its possible but problem is atom from the small body may be released and actually bring the weight of the object down. Thus its very hard to test this idea, I can't define right now any experiment that could be used to check if this idea is right or wrong.

Right now it could only be tested or checked against the gravity anomaly and trust me (I bet you don't) I didn't make up this idea based on the anomaly, as this is a new theory area I'm more than willing to put my theory here.

Maybe its wrong, I'm not saying its right but its a concept of linking and understanding nature of our universe in a different way.

Secondly as far as "things getting lighter when heated" is concerned, maybe I'm missing a point and I am totally wrong, but for the time being I don't see anything giving an answer to fact why less denser objects move away from source of gravity at Quantum level. Maybe you find this formulation in Classical mechanics where things rise when they are less dense but it has no explanation in Quantum mechanics.

#### MikeS

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##### Re: Why when things are heated they become lighter?
« Reply #13 on: 11/03/2012 20:08:59 »
grienniemax

If you read my last post again you will see that I never said gravity had nothing to do with it and never said it would work in the absence of gravity.  That's not what I said and not what I meant.

What I did said was "Energy is subject to entropy and one way of accomplishing that is by dispersal."  This effect is greater than the energies gravitational attraction as I said "It is true that according to GR energy has gravity but I believe its dispersal tenancies far outweigh any gravitational attraction that it may possess."

Meaning that if energy in any way possesses gravity then the effect is minute in comparison to its tendency to disperse.
« Last Edit: 11/03/2012 20:11:07 by MikeS »

#### greeniemax

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##### Re: Why when things are heated they become lighter?
« Reply #14 on: 12/03/2012 09:50:36 »
Sorry MikeS,

I put your name there by mistake actually.

#### MikeS

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##### Re: Why when things are heated they become lighter?
« Reply #15 on: 12/03/2012 12:18:56 »
Sorry MikeS,

I put your name there by mistake actually.

Ok

#### The Naked Scientists Forum

##### Re: Why when things are heated they become lighter?
« Reply #15 on: 12/03/2012 12:18:56 »