energy in an atom

[Gaston]

as i understand, the electrons in all atom are constantly moving around the nucleus. so an atom makeing up a rock in the core of a mountain that is millions of years old has electrons in it that have been revolving around for at least that long. where is the energy coming from and why doesn't it run out. i can understand the planets revolving around the sun because it dosent take any energy because there is no drag in a vacuum. doesn't this seem like perpeptual motion?

 

[dknguyen]

What makes you think there is no vacuum between the nucleus and orbiting electrons? It's not like there are air molecules (humongous by comparison) squeezing in between the electrons and nucleus to cause drag.

As far as collisions go, collisions between electrons are perfectly elastic.

But yeah, we are beyond the laws of Newtonian physics, so you can't really compare the two on the same terms...or can you?

 

[Hero999]

If there is no energy being lost to the environment then it is perfectly possible to have perpetual motion. For example if you were to make a totally lossless flywheel and spin it, it would never stop because the system isn' loosing any energy.

Atoms contain a lot of energy, this is known as the binding the energy and is what is released when a neuclear reaction occurs.

 

[Oznog]

Well, here's something you need to understand.

What happens at the subatomic level is completely different rules than what you know. Our metaphors fall short. We paint electrons as a black ball around protons and neutrons stuck together like soap bubbles to keep from scaring the kids.

For one, note an electron has no color since for items shorter than a visible wavelength, color does not exist.

Another commonly accepted principle maintains an electron does not have a location, simply a region of probability. The ramifications of this are deep.

Conventional wisdom suggests an object such as an electron could be slowed down and thus assume a closer orbit, or gradually sped up into a higher orbit. All we really know is it can't. "Why" is a matter of speculation. Even the best physicists can't really say why, they can just say what it does. They'll write out a big formula showing why, but the formula is merely based on the observations that this is what they do, making this logic rather redundant.

Actually while "perpetual motion" literally means motion that is never dampened, its normal use is motion that you can take free energy off of without it slowing it down. The waterwheel running a lifting pump to bring the water back up, as well as a generator to light a light bulb. Well, an electron can't do that for sure.

As far as the literal form of "perpetual motion", it is and it isn't. It won't ever "slow down", but the electron's orbit is not motion in any literal sense to begin with. The "motion" description is a metaphor to try to picture a property that is otherwise incomprehensible because there's nothing like it in the observable world.

 

[Gaston]

so the electrons don't actually orbit the nucleus as the planets orbit the sun? but rather the orbit is just were the electron could probably be but stationary? while we are on the subject, is gravity the same thing as the force that holds the electrons to the nucleus? if not, is it similar?

 

[kchriste]

Another commonly accepted principle maintains an electron does not have a location, simply a region of probability. The ramifications of this are deep.

Or, in other words, humans cannot figure out exactly where it is....
It is always good to be able to throw away "commonly accepted principles" at a moments notice. For example, the word atom is derived from Greek which means indivisible. Now we know better.

The "motion" description is a metaphor to try to picture a property that is otherwise incomprehensible because there's nothing like it in the observable world.

Sometimes I think, by using names and metaphors, we actually end up confusing ourselves.

 

[Oznog]

so the electrons don't actually orbit the nucleus as the planets orbit the sun? but rather the orbit is just were the electron could probably be but stationary? while we are on the subject, is gravity the same thing as the force that holds the electrons to the nucleus? if not, is it similar?

In some senses, you can look at like a planet orbiting a sun, but in reality that metaphor will fall through. It may not be moving at all in the conventional sense.

Gravity is seen as one of the basic 4 forces. Electromagnetism (electricity and magnets are seen as 2 sides of the same coin), gravity, Strong, and Weak.

This may sound mind-blowing, but we actually understand very little about gravity. There is even a big argument over how fast gravity travels- for example, if the sun were suddenly yanked away from the center of the solar system by an inconceivably huge rope, how long would it take for the Earth's orbit to change? There have been some various evidence, the best evidence shows much faster than the speed of light but apparently still not instantaneous.

The irony is that while gravity is the most obvious force you sense every day, it's also one of the weakest. It's hard to get a readable force from a lab experiment because the gravity from even a 10-ton sphere of iron is still phenomenally small. With magnetism we can make a concentrated field with an electromagnet, not so with gravity.

 

[dknguyen]

while we are on the subject, is gravity the same thing as the force that holds the electrons to the nucleus? if not, is it similar?

No, gravity is not the force that holds electrons to the nucleus. It's the electro-weak force I think it is called. Kind of like the electric field stuff holding charges- but not.

The super powere I would like to have is the manipulation of gravity.

Gravity is the weakest, but extremely tenacious and stretches vast distances...plus let's not forget black holes (if you believe they exist)

 

[HiTech]

The atoms that make up the rock, that makes the mountain are not forever fixed --- so to speak. While their energy is conserved or transforms into other forms of energy, mountains do change shape and weather away. This means their material, yes down to the atomic level is changing too. If it weren't, then the mountain would never alter in size, shape & appearance. Alot of things going on in "Inner Space". There is a theory that gravity may exist in varying concentrations and could be exponentially intense in another dimension or a "brane".

 

[Phasor]

Or, in other words, humans cannot figure out exactly where it is....

This is the Heisenberg uncertainty principle. In lay terms, at any given moment, we can measure the position of a particle, but not its velocity; or, we can measure its velocity, but not its position.

Pick up a first year Physical Chemistry textbook, and it will show you the "regions of probability" for various electron shells.

 

[Oznog]

It gets weirder when you look up the "double slit" experiment. There's several versions. First they did it with ordinary light and show light is a wave due to the interference pattern in creates.

Then they did it with electrons and showed that electrons also behave as waves. Yet the hits are individually points of impact. Each impact is not spead out in any way. The only answer that makes any sense is the probability of where the electrons coming through first slit are were affected by the presence of the electrons going through the second slit.

It gets SUPER weird when they made an electron source that fired electrons one by one. There is no way two electrons were travelling through different slits at the same time. So you'd expect to see a hit pattern that looks just like the sum of closing one slit, letting 100 electrons through the other, then change slits and fire another 100. That doesn't happen! Somehow the mere presence of the second slit- which the electron didn't go through- has created an interference pattern.

This test has been done over and over and the theories have to be really bizzare! The best explanation is that the electron has a 50% chance of going through either slit, and in fact that single electron apparently did go through both slits at the same time. The probability split up, but there's only one electron! Apparently only when you create a target for it to hit does it decide where it is and which slit it went through.

Look it up. The consequences of that single-shot electron experiment are truly mind-boggling. You can never look at reality the same way again once you understand what happens with that experiment.

 

[Aily Sajjad]

as i understand, the electrons in all atom are constantly moving around the nucleus. so an atom makeing up a rock in the core of a mountain that is millions of years old has electrons in it that have been revolving around for at least that long. where is the energy coming from and why doesn't it run out. i can understand the planets revolving around the sun because it dosent take any energy because there is no drag in a vacuum. doesn't this seem like perpeptual motion?

I think this is the energy from surrounding temperature that keep things (including electrons) in activity. That's the reason cfo contraction and expansion. AT absolute zero all activities will seize electrons will fall into the nucleus.

What do others think?

Aily

 

[Hero999]

That's not true, electroncs are very active at absolute zero, if that wasn't the case then there would be no such thing as super conductors.

 

[Aily Sajjad]

Basically,

We cannot reach absolute zero Temp. What we believe as absolute zero is actually still relative temperature.

Aily

 

[Aily Sajjad]

An extract from wikipedia:

Absolute zero is the lowest possible temperature where nothing could be colder and no heat energy remains in a substance. Absolute zero is the point at which molecules stop and they have minimal movement vibrations or none, retaining only quantum mechanical, zero-point energy-induced particle motion.

By international agreement, absolute zero is defined as precisely…

0 K on the Kelvin scale, which is a thermodynamic (absolute) temperature scale, and
–273.15 °C on the Celsius scale.
Absolute zero is also precisely equivalent to…

0 °R on the Rankine scale (also a thermodynamic temperature scale), and
–459.67 °F on the Fahrenheit scale.
While scientists cannot fully achieve a state of “zero” heat energy in a substance, they have made great advancements in achieving temperatures ever closer to absolute zero (where matter exhibits odd quantum effects). In 1994, the NIST achieved a record cold temperature of 700 nK (billionths of a kelvin). In 2003, researchers at MIT eclipsed this with a new record of 450 pK (0.45 nK).



Aily

 

[Optikon]

That's not true, electroncs are very active at absolute zero, if that wasn't the case then there would be no such thing as super conductors.

Nothing in our universe gets to absolute zero. Not even superconductors. Perhaps the moment (ill-defined) just before the big-bang of the universe existed as absoluete zero temp. And electrons are tendencies.. not "things."

 

[Hero999]

But we've achieved close enough.

Anyway the idea that electrons move less at lower temperatures sounds silly when the conductivity of most metals approaces 0hm: at very low temperatures; if electrons were stopped moving then the reverse would be the case but it isn't.

 

[dknguyen]

Nothing in our universe gets to absolute zero. Not even superconductors. Perhaps the moment (ill-defined) just before the big-bang of the universe existed as absoluete zero temp. And electrons are tendencies.. not "things."

Uhhh, electrons are matter aren't they? I don't think you can define some matter as a tendency and other matter as things.

 

[Pommie]

As you guys appear to understands gravity, can you please explain the following.

It is a well known fact that planets orbit around suns. The nearer the planet to the sun the faster it must orbit. The same is true for stars orbiting around galaxies. With this in mind, how can a spiral galaxy be stable? Surely, after a few rotations the spiral will turn into a disc.

Mike.

 

[kchriste]

Surely, after a few rotations the spiral will turn into a disc.

Maybe, but it'll be hard to tell because one rotation is a VERY long time. We can look at older Galaxies and guess that one of the disc type ones was like ours once, but there is no way to prove it.