I wanted to point out that depending on the state of the matter, it will form structures like for instance a crystal matrix.

This is called a solid.

 

Hello,

The following page might give you some idea about the atoms and the molecule structure:
http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookCHEM1.html

This is a link from the EDUCYPEDIA page on Atoms

Bertus

PS keep in mind that the OP is a boy of about 12 years old.
@ The Catapult, you may correct me if I am wrong.

 

Technically, not true: PV = nRT . Solid helium can be a solid at sufficiently low temperatures at 'normal pressure' and constant volume, according to the Ideal Gas Law, which, I know is not universal, does capture the behavior of gases.

Uhm... it called the "gas" law for a reason. It doesn't apply to liquids or solids at any temperature or pressure. Think about it.

 

Uhm... it called the "gas" law for a reason. It doesn't apply to liquids or solids at any temperature or pressure. Think about it.

Sorry, typing faster than thinking... I was on the track of thinking that the ideal gas law will play a part in the gaseous region of the phase diagram...

perhaps you should take another look at phase diagrams...
http://ltl.tkk.fi/research/theory/he3.html

http://www.phys.ufl.edu/courses/phy4550-6555c/spring09/properties.pdf

http://hep.ph.liv.ac.uk/~hock/Teaching/393_LowTemp_1.pdf

 

The ideal gas law and phase diagrams are two very different things. The ideal gas law is an approximation for the physical characteristics of a GAS -- not of a solid, not of a liquid. Even then, the quality of the estimate falls apart at sufficiently high pressures or sufficiently low temperatures because the fundamental assumption, that the volume occupied by the gas atoms/molecules is insignificant compared to the total volume) becomes increasingly invalid.

A phase diagram describes the state of matter as a function of various variables, typically pressure and temperature. It is not in any way even remotely synonymous with the ideal gas law.

But look at the phase diagram in the first link you provided in light of your claim that "Solid helium can be a solid at sufficiently low temperatures at 'normal pressure'...."

Now, "normal pressure" means something in the vicinity of standard atmospheric pressure, which is ~0.1MPa. The diagram shows that even at a tiny fraction of one millikelvin that He3 is not a solid unless the pressure is in the vicinity of 3.5MPa, or well over 30 atmospheres (something around 500psi).

Now look at the slides in the second link you provided. It explicitly states that helium "remains a liquid even at absolute zero (unless external pressure is applied)".

Now look at the slides in the third link. It explicity (and in red) states "under atmospheric pressure liquid down to T=0," and further states, "No triple point (where gas, liquid, solid coexist)," and "Near T=0 solidified for P>33atm."

Again, I ask that if you think the ideal gas law applies to solids or liquids that you think about the implications if it did. If you have a solid block of ice (say at -3C) sitting in a container open to atmosphere (let's call it 15psi) and you then pressurize the container to 30psi (15psi guage), do you expect the volume of the ice to drop in half? If you expect the volume to stay the same, do you really expect the temperature to double to ~270C (~500F)?

 

Retroactively stating what normal pressure is is a bit of a cop-out. I mean, normal pressure for a star? Normal pressure for a black hole? You failed to mention that. Atmospheric pressure is a understandable measure of pressure, 'normal pressure' is not.

A phase diagram shows what the relationship between phase and two other variable are while all others are constant. As such, it is not simply a one or the other relationship.

Perhaps you should read before posting, I said I had made a mistake in writing Ideal Gas Law.

 

Retroactively stating what normal pressure is is a bit of a cop-out. I mean, normal pressure for a star? Normal pressure for a black hole? You failed to mention that. Atmospheric pressure is a understandable measure of pressure, 'normal pressure' is not.

The terms "normal pressures" and "normal temperatures" are widely used and widely understood. There is even a formally defined NTP (Normal Temperature and Pressure) which is just slightly different from STP (Standard Temperuature and Pressure).

Perhaps you should read before posting, I said I had made a mistake in writing Ideal Gas Law.

At the time I posted my response, that statement wasn't there. Your post started with "perhaps you should take another look at phase diagrams..." Most likely, you edited your post while I was writing my response to your original one. The timestamps are quite consistent with that. That's one of the reasons why I dislike edits that affect content (as opposed to typos), since it easily makes it impossible to follow the flow of the thread.

 

The terms "normal pressures" and "normal temperatures" are widely used and widely understood. There is even a formally defined NTP (Normal Temperature and Pressure) which is just slightly different from STP (Standard Temperuature and Pressure).

Hmmm... I was unaware that normal has a specified meaning... then I'll cede the point. I was mistaken with respect to the possibility of, at normal pressure and while all other variables are constant, temperature being the sole factor in transitioning liquid He to a solid.

At the time I posted my response, that statement wasn't there. Your post started with "perhaps you should take another look at phase diagrams..." Most likely, you edited your post while I was writing my response to your original one. The timestamps are quite consistent with that. That's one of the reasons why I dislike edits that affect content (as opposed to typos), since it easily makes it impossible to follow the flow of the thread.

True, I had rushed to post only to realize I hadn't written that part. However, it was a full twenty minutes later that you posted your response...

 

Hmmm... I was unaware that normal has a specified meaning.

FYI:
NTP = 70F @ 1 atm
STP = 15C @ 1 atm

NTP is used less and less as time goes on.

True, I had rushed to post only to realize I hadn't written that part. However, it was a full twenty minutes later that you posted your response...

Yes, and it took me well over twenty minutes to write my response. Since I started working on my response before you made your edits, I never saw them. Consider that I had to load and go through the material from all three of the links you included as well as look up other things.

I think we've beaten this one to death and, at the end of the day, are finally on the same page.

 

Is this topic under the Optics of Physics?

 

Hello,

Optics can be seen as part of physics.
Optics has all to do with waves.
You will find optics subjects under the physics heading of this page:
http://educypedia.karadimov.info/education/educationopening.htm

You will find the atoms and molecules under the chemistry heading of the same page.

Bertus

 

Is this topic under the Optics of Physics?

Yes and no. As pointed out a few times, light has a dual nature in which it is both a particle and a wave. In situations in which treating it as a wave only is good enough, we call that optics (though I think now the actual term in use is more commonly "classical optic" or "wave optics". Once you move into situations in which a wave-only approach is no longer good enough, you are basically in the realm of modern physics and quantum mechanics. I seem to recall it also being referred to by terms such as "photon optics".

 

Yes and no. As pointed out a few times, light has a dual nature in which it is both a particle and a wave. In situations in which treating it as a wave only is good enough, we call that optics (though I think now the actual term in use is more commonly "classical optic" or "wave optics". Once you move into situations in which a wave-only approach is no longer good enough, you are basically in the realm of modern physics and quantum mechanics. I seem to recall it also being referred to by terms such as "photon optics".

I've heard it referred as photonics...

 

I've heard it referred as photonics...

Hmmm. Possibly. That term has always (to me) implied "photo electronics", or electronic devices and circuits that emit, detect, or process light, such as those used in fiber optic circuits or laser scanners. It may be used for both.

 

posted link does not open. Should have checked first.

 

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I am bringing this back again for another similar question.

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Are we, humans, objects, etc physically perfectly intact? (Having no holes of any size?) Assuming, atom is circle in shape, I think we are not.

Thanks!

 

--------------------

I am bringing this back again for another similar question.

-----------------------------------------------

Are we, humans, objects, etc physically perfectly intact? (Having no holes of any size?) Assuming, atom is circle in shape, I think we are not.

Thanks!

Nothing in the universe has no holes, or gaps, of any kind.

 

--------------------

I am bringing this back again for another similar question.

-----------------------------------------------

Are we, humans, objects, etc physically perfectly intact? (Having no holes of any size?) Assuming, atom is circle in shape, I think we are not.

Thanks!

Go back to what I said pretty early on. All matter is almost entirely empty space. The volume occupied by the nuclei of the atoms is tiny compared to the macroscopic volume of the object and the volume of the electronics is miniscule compared to the volume of the nuclei. So the electrons are swimming arround in a gulf of emptiness between very dense nuclei.

 

Okay.

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Think of any solid material. Get a flashlight or anything that produces light, and put it in the front of that solid material, e.g. a metal cube.

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You will see that the light was blocked by the metal cube. Why is it so? We have agreed that atom has holes, you even said that it looks like an empty space. So why light can't penetrate to the holes?

Maybe because the photon, or whatever it is called, is too large compared to the holes so it cannot penetrate.

Whatever the reason, what is it?

Sorry for many questions and bringing this thread back again.

Lightfire

 

If you only consider light passing through a material in terms of the "holes" in the material or the empty space between atoms, then you will have an impossible time trying to explain why light DOES pass through some materials (glass) and not others (metal).

The interaction of light with matter is a very complex thing. Why is some light absorbed? Why is some light transmitted through? Why is some ight reflected? Why is some light scattered? The simple explanations we use are useful analogies, but like any analogy, can't be pushed too far. To get to those, you have to look at the interactions between the electromagnetic fields that make up the light and the electromagnetic fields associated with the electrons and nuclei that make up the matter.