Ask a physicist anything. (6)

[Lillen]

But in steem have the same mass nomatter what state it is in?

 

[chris4243]

How can watermolkules be lighter then air? - It is the same molecule in whatever state it is (Solid, Fluid or Gas)!

A water molecule weighs 2X1+16=18 atomic mass units (AMU). 1 AMU for each of 2 hydrogens, 16 AMU for the oxygen. The oxygen (O2) molecule weighs 2X16=32 AMU, and the nitrogen (N2) molecule weighs 2X14=28 AMU. There's other molecules that compose the air too, but nitrogen and oxygen make up most of it, and water molecules are almost half as heavy.

However, you are familiar with liquid or solid water, which though made of light molecules is much denser because the molecules are very close together. But in a gas, the molecules are spread about the same distance regardless of what the molecule is, and so it depends largely on the mass of the molecule.

 

[Chalnoth]

How can watermolkules be lighter then air? - It is the same molecule in whatever state it is (Solid, Fluid or Gas)!

That isn't actually that important. Carbon dioxide, for example, has a typical mass of 44 AMU, while water has a typical mass of 14 AMU. And carbon dioxide is a gas at much lower temperatures than water.

Radon, which has a typical mass of 222AMU, is a gas all the way down to -62C/-79F.

So it really doesn't have much to do with the mass. Rather, it's how strongly the molecules stick to one another. It turns out that water molecules stick to one another quite a bit more strongly than carbon dioxide molecules, and that is the reason why water is a liquid at the same temperature that the heavier carbon dioxide is a gas.

But even while water is a liquid, some of the atoms in the bunch of water are going to have (or gain) enough energy to escape the water and enter a gaseous state.

 

[mzungu]

The reason why i believe those others lie, is because they don't seem to got a clue of what themself say!

So you are saying that water can evaporate under 100C?



We agree!!

Yes water evaporates at less than 100c. How do you think your clothes dry? The boiling point of water changes with the barometric pressure. The lower the pressure the lower the boiling point. In fact on Mars the air pressure is solow and the temperatures are extremely cold yet water will instantly boil and evaporate at these temperatures. If an astronauts suit is breached then his blood will boil even at his body temperature.

Also and lastly I have this request to you: Please do not taunt us by calling us liars and please refrain from acting in a manner that resembles that of trolling.

 

[Lillen]

I try to follow you... I really try!

And I repete - water molekules have the same mass nomatter which state it is in, or?

 

[Wiccan_Child]

The reason why i believe those others lie, is because they don't seem to got a clue of what themself say!

The answers given are very good answers. Is it the language barrier that prevents you from understanding them?

So you are saying that water can evaporate under 100C?

I'm saying that a body of water with an average temperature of less than 100°C can evaporate, yes. Have you never noticed that, when left to their own devices, a puddle that formed during a storm evaporates all on its own?

How can wolves in sheep clothing evaporate?

They can't. Evaporation is a state change from liquid to solid. As they're solids, wolves in sheep's clothing could at best sublimate.

Wolves are running naked in the woods, and crocodiles are swimming naked in the swamp, why!!?

Because they live in climates best suited for their level of fur/scales. Humans, who migrate about and have smart brains, invented clothing to keep themselves warm.

Back to the questioning: Do you answer history and social sciences under this topic as well, I see that it is under lifesciences?!

Yes: the established tradition is that you can ask a physicist anything.

How can watermolkules be lighter then air? - It is the same molecule in whatever state it is (Solid, Fluid or Gas)!

It's 'lighter than air' because, as a gas, it's about the same density as air. As a liquid, it has a much higher density. Thus, it can be 'suspended' in air when it's a gas, but not as a liquid. It has little to do with the molecule's actual weight, however.

Thank you! We can revoke gravity! Rapture soon will come! We found another perception of gravity!

Not quite.

 

[Lillen]

They can't. Evaporation is a state change from liquid to solid. As they're solids, wolves in sheep's clothing could at best sublimate.

From liquid to gas you mean? Or am I mixing up the concepts?

 

[Mr. Pedantic]

As for the trolling part... i think that is an excuse for you to disregard me!

No, it is me applying the most charitable explanation for why you are acting as if you are ignorant of basic chemical and physical properties of the world. If you don't understand an answer, and you sincerely want to know, ask us to clarify, or use simpler language. Don't call us liars. I find it impolite, to say the least. Even on the internet.

 

[Wiccan_Child]

From liquid to gas you mean? Or am I mixing up the concepts?

Sublimation is when a solid turns straight into a gas. As a wolf is more or less a solid, to turn into a gas it has to sublimate.

 

[Mr. Pedantic]

Sublimation is when a solid turns straight into a gas. As a wolf is more or less a solid, to turn into a gas it has to sublimate.

Not really. Wolves are more or less liquid. Parts of them are solid, but most is liquid. The classic example is carbon dioxide; (at normal pressures at least) it has no liquid phase; when you heat it it goes straight from solid to liquid.

 

[Wiccan_Child]

Not really. Wolves are more or less liquid. Parts of them are solid, but most is liquid.

Most of their molecules are liquid, sure, but the wolf itself as a complete object is more solid than liquid (consider a matrix of solid with hunks of liquid in it; you need to sublimate the matrix rather than evaporate the liquid).

It was a joke anyway...

 

[mzungu]

WOW!!!! This is weird and mind blowing!

‪Superfluid helium‬‏ - YouTube

 

[Wiccan_Child]

‪induction heater levitation melting aluminum‬‏ - YouTube

God I love science.

 

[mzungu]

‪induction heater levitation melting aluminum‬‏ - YouTube

God I love science.

Oh I'm with you mate! Man what a rush science gives me!

 

[Lillen]

Another question I have: how can we messure the distance between the earth position in january respectivly july?

 

[Lillen]

Ooh sugar and salt... You can have that for free WC from me!

I knew a man who were cutting diamonds with his Bischon Freise! When that man gave the dog a female Bischon Freise to mate with, they breed puppies with squinting eyes!

As i've heard, it is the most aggressive dog out there!

 

[Wiccan_Child]

Another question I have: how can we messure the distance between the earth position in january respectivly july?

The distance between the Earth's position in January and July can be calculated by working out how far away the Earth is from the Sun at those points in time. This site has a good list of explanations of how we know various things about the Solar System.

 

[Chalnoth]

The reason why I called you liars, was because you uttered yourself in such manners that you gave me the impression that you didn't have a clue of what you were saying! You advanced without been given the clearanced by science... But I see that most of you repented, so now I am glad for you!

Well, it might be better to try to explain what it is that you think is wrong, and most especially why you are suspicious. So far in this thread you haven't clarified one thing that you think may be wrong. If you don't explain where it is that you think there is an issue, there really isn't any chance of resolving the issue.

 

[Chalnoth]

Another question I have: how can we messure the distance between the earth position in january respectivly july?

Now that is a pretty interesting question. This primarily depends upon the distance between the Sun and the Earth, and we can't exactly extend a tape measure between the Earth and the Sun. But again, we can make use of geometry: we can exploit the distance between the Earth and the Moon to estimate the distance to the Sun. This is done by comparing the shadow of the Sun on the Moon (which gives us the angle the Sun makes with the Moon) to the angle the Sun makes with the Earth. Comparing these angles gives us the distance to the Sun as a ratio of the distance to the Moon. And these days, we can measure the distance to the Moon extremely accurately by bouncing lasers off of it (the astronauts that landed on the moon left reflectors behind for this exact purpose).

 

[Naraoia]

Sort of. It doesn't necessarily require the laws be the same looking forward as backwards (though all of our more fundamental laws of physics are symmetric in time).

The term "unitary" comes from linear algebra. In linear algebra, unitary transformations are the generalization of rotations. When you rotate a system, you're just looking at the same system from a different angle. It may look different, but it's really the same system.

I see.

(And trying to grasp exactly what you mean by "generalization of rotations", I learned what an "inner product" is. Ah, vectors, sometimes I really do miss playing with you! )

For more distant objects we can use the red-shift that Hubble found, and analyzing the emission spectrum of the object in question, and comparing it to what we know it is made of. The amount of red-shift is a rough indicator of distance.

Cepheids! Don't forget cepheids!