Mind boggling facts that make you go..

aardvark said:
its all about the electrons - metals have a huge delocalised layer of electrons and so they absorb a very broad range of em radiation (but not all as you said, especially the higher energy waves).
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The electrons suck, so to say, all trying to pass through the materials photons?
 
Roland Butter said:
How about the empty space between your ears, you just made that up didn't you ?
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Maybe it's just because of my interest in physics but I thought that was quite a well known fact tbh, not sure why you are having trouble believing it, especially since Dimple linked to a physics article that backs him up
 
Freakbro said:
Maybe it's just because of my interest in physics but I thought that was quite a well known fact tbh, not sure why you are having trouble believing it, especially since Dimple linked to a physics article that backs him up
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I too thought it was pretty commonly known. What still gets me is every electron in your body is simultaneously where you expect it to be and not there too.
 
Orionaut said:
That is actually a good question.

The empty spaces are filled with incredibly powerful and complex electric fields.

Sometimes light can pass through them (EG Glass) sometimes it cant (Steel)

But you have to remember that there is no such thing as light. It is just EM radiation. some configurations of electric field will allow certain wavebands of EM radiation to pass unhindered, some wont

I am sure that somebody will come along with a better explanation. But this is really no different as to why microwaves can pass through (non-transparent) plastic but are blocked by (Transparent) Water
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Slightly related, my company build lasers, and different materials allow light of different wavelengths tthrough.
 
I think one of the most amazing things is that we now know that the Universe actually did have a beginning and that we know how long ago it was...

Not only that but barring the first tiniest fraction of a second, we seem to have developed a pretty good understanding of how the universe evolved from that time to the current day.

Now, we still dont know how it came into being in the first place (And may never know) we dont know how large it is and we dont know what will happen eventually.

Nor have we yet figured out the "Dark matter/Dark energy" thing. And there are undubtedly many more things yet to learn about the true nature of the universe.

But Most of what we do now know has been worked out within less than a single human lifetime.

Which is pretty damn good going really!
 
Trappi$t said:
The 2nd part of this is rubbish. Air rushes out of an airlock due to differential pressure.
1st part is questionable also, as molecular air movement is wholly dependent on temperature.
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erm no...actually he's correct :p

Speed of sound is 330 m/s in air, which is around 740 mph. So, air molecules *must* be moving at least that speed at room temperature and pressure.
 
I fancy boys said:
erm no...actually he's correct :p

Speed of sound is 330 m/s in air, which is around 740 mph. So, air molecules *must* be moving at least that speed at room temperature and pressure.
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No,

Sound is a pressure wave, not the movement of air as such.

Think of electricity in a wire.

An electric signal can propagate along a wire at a good proportion of the speed of light. However the speed at which individual electrons move within the wire is very slow indeed, mm/s or even less.
 
Some interesting facts:

There are more experts on Islam on these forums than there are Muslims in the world.

Bees can fly higher than Mount Everest.
 
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Orionaut said:
No,

Sound is a pressure wave, not the movement of air as such.

Think of electricity in a wire.

An electric signal can propagate along a wire at a good proportion of the speed of light. However the speed at which individual electrons move within the wire is very slow indeed, mm/s or even less.
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I agree. Perhaps I should have been clearer; I didn't mean to imply that sounds moving from A to B is a series of molecules moving along the same distance. However, the speed at which they can transmit information will be governed by the mean speed between collisions, which in this case is around 1000 mph.

Same with electricity in a wire, net electron motion is very slow, but the mean speed between collisions is around 10^7 cm/s.

So, he's right - the particles themselves are hitting us at around that speed.
 
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