Sciencemadness Discussion Board - Why don't the electrons slam into the protons?

Why don't the electrons slam into the protons?

jgourlay - 12-5-2009 at 08:43

Yet another stumper from my 4 year old (the insightful one).

"Daddy, if the negative electron and positive proton are attracted, how come the electron acts like a planet around the sun? How come they don't bam into each other?"

I assume the right answer is not, "shut up and eat your carrots!"

watson.fawkes - 12-5-2009 at 09:02

Quote: Originally posted by jgourlay

"Daddy, if the negative electron and positive proton are attracted, how come the electron acts like a planet around the sun? How come they don't bam into each other?"

"They don't because of quantum mechanics." Really, this is the right answer. When you get to electrons in atoms, naive classical physics analogies break down and no longer provide true insight. The thing to teach is that models are approximations to reality, not generators of reality, and that every model has some non-universal realm of applicability.

The atomic problem is, indeed, the first major triumph of QM, not for hydrogen (for which the semi-classical model sufficed), but for helium, for which the Schrodinger equation correctly predicted the spectral lines.

jgourlay - 12-5-2009 at 09:06

Yeesh....

I get it. However, it's difficult to communicate that to a youngster. They conceptualize so literally. Their little brains have difficulty with constructs like "model".

turd - 12-5-2009 at 09:27

"Daddy, if the earth and the sun are attracted, how come the earth acts like a planet around the sun? How come they don't bam into each other?"

Just don't tell him that charged particles going around corners are supposed to lose energy and you won't have to explain him QT.

Sobrero - 12-5-2009 at 10:00

Hmm the answer "Because Daddy says so." is quite unscientific too ^^.
Perhaps you can tell this too:

Electrons are negatively charged and protons positively, but that doesn't imply that an electron orbiting around a proton will collapse on the proton, because the centrifugal force opposites the Coulomb force.
But from electrodynamics we know that an accelerating charged particle radiates energy in the form of electromagnetic radiation. Thus the kinetic energy of the electron decreases, and because the radius of the orbit is related to the kinetic energy of the electron, the radius decreases too and so after a very short while they collapse.

Bohr's semi-classical model resolved this problem by bluntly postulating that:
- the angular momentum of the electron is quantised (and so also the radius and energy of the electron is quantised).
- the electron in its lowest energy state doesn't radiate energy.

The quantum mechanical model postulates that a system's wave function obeys the dynamic Schrödinger equation. When solving that equation for a system comprising a proton and an electron, it turns out that energy is quantised, and that the lowest energy state is non-zero, so the system is stable.

Well at least that's what I recall from my course of Molecular Structure

watson.fawkes - 12-5-2009 at 10:42

Quote: Originally posted by jgourlay

I get it. However, it's difficult to communicate that to a youngster. They conceptualize so literally. Their little brains have difficulty with constructs like "model".

Well, you don't have to explain QM with wave functions and eighenvalues, any more than you've explained Newtonian mechanics with the Euler-Lagrange equation.

How about this: "An electron is a little cloud of sparkle. It looks like a single spark from far away, but up close you can see it's a cloud. You can't squish the cloud down to a little point, so it spreads out a little but mostly surrounds the proton."

jgourlay - 12-5-2009 at 11:29

Watson, that's perfect!

watson.fawkes - 12-5-2009 at 13:27

Quote: Originally posted by jgourlay

Watson, that's perfect!

Thanks.

The language "when it's up close" vs. "when it's far away" is the implicit cue to switch models. Whenever you need to switch models when explaining science, the key is to find a distinction in context, then to put language to the distinction. This provides the opportunity to tell a different story.

In the present case it's a scale difference that's physically relevant. So the key is to find sensory intuition that is homologous to a scale difference. Large objects start to look like points from far away, so that's the grounding of the alternate context.

len1 - 12-5-2009 at 14:49

I dont think these are the answers. Newtons second law explains why the moon doesnt fall into the earth, but Schrodinger's equation does not explain 'why' electrons and protons dont slam, into each other. In fact according to it they do, there is a small probability for the electron to be located over the nucleus - in common parlance 'hitting' the nucleus. Nor is semiclassical theory adequate for the hydrogen atom but not for others, I dont know where that comes from.

One must remember that the electron 'wanders' over an average ball of radius 10^-10 meters. The nucleus is constrained to 10^-15. So 10^-15 of the electron is located over the nucleus. For a child - the electrin swirls around the house while the proton the size of the tip of a needle sits in the centre. This reduces the probability of their interaction. What really protects the atom is Baryon number conservation - nucleons are Baryons and any known reaction conserves their number. The electron and proton can not annihilate. But I guess we are just running around in circles - explaining one empirical fact, by another of more general applicability, at the expense of greater abstraction.

The ordinary Schrondinger equation also does not explain why the atom is stable against radiation - it just uses Coulombs law - so it knows nothing of radiation. For that you need quantised Maxwells equations (called the Dirac equation).

[Edited on 12-5-2009 by len1]

turd - 12-5-2009 at 22:20

Yes, len1, you gave the only correct answer so far. IIRC, the probability density function for s electrons takes its highest value at the centre(!). Therefore your estimate of 10^-15 is probably pessimistic (multiply the probability density functions of electron an protons and integrate?). The correct answer would therefore be: "they constantly smash into each other" or "they do overlap". But there's are reason 4 year olds aren't quantum physicists and therefore the really correct answer might actually be "shut up and eat your carrots". (I kid...)

[Edited on 13-5-2009 by turd]

watson.fawkes - 13-5-2009 at 06:11

Quote: Originally posted by len1

Nor is semiclassical theory adequate for the hydrogen atom but not for others, I dont know where that comes from.

The semiclassical model adequately predicts the Lyman, Balmer etc. series of emission lines—all those from the Rydberg equation. The reason is that there's only a single electron. The helium atom has electron-electron interactions that were not accounted for adequately in the semiclassical model. When Schrodinger's equation first came out, it was immediate to derive Rydberg's equation from it. That wasn't persuasive in itself, though, because there was existing theory that accounted for that equation. It wasn't until the helium spectrum was derived that proof was definitive.

DJF90 - 13-5-2009 at 06:51

turd: The probability density function for the s-electron does not take its highest value at the nucleus!! There is however, a non-zero probablility of finding an s-electron there though, because the s-electron is deeply penetrating. The actual probability of finding the electron at the nucleus is small.

The bohr condition leads to a quantisation on the radius of the electron orbit (the electron can only occupy an orbit that possesses an angular momentum, L, that is an integer multiple of the reduced plank's constant (h/2pi), i.e. L=(nh)/2pi. This is known as the Bohr condition, and leads to the conclusion that energy is quantised.

By combining De Broglie's equation with the Bohr condition shows that the circumference of the orbit of radius r must be an integer multiple of the electrons De Broglie wavelength.

This quatisation of energy must somehow link into the fact that the electron does not collide with the nucleus. Perhaps the electron does head for the nucleus but experiences the "catapult effect" and so never actually collises with nucleus?

watson.fawkes - 13-5-2009 at 07:00

Quote: Originally posted by DJF90

turd: The probability density function for the s-electron does not take its highest value at the nucleus!!

Actually, it does for 1s electrons, but only for those. All other electrons have a density zero at the origin. The central potential solutions of Schrodinger's equation are a spherical Bessel function times a spherical harmonic. The spherical Bessel functions are approximately a monomial in the power of the principal quantum number 'n' (total energy). Only when n=0 is this density not zero at the origin.

turd - 13-5-2009 at 09:24

Quote: Originally posted by DJF90

The actual probability of finding the electron at the nucleus is small.

Of course, because the nucleus is small. The probability of finding an electron in a volume element V is given by the integral of the density function over V. Therefore (since our density function is real*) the probability of finding an electron at (x,y,z)=(0,0,0) must be 0. But the probability of finding an s-electron in an infinitesimally small volume element around (x,y,z)=(0,0,0) is higher than finding it in _any_other_ volume element of the same size. Maybe you were thinking about the radial probability density function, which gives the probability of finding an electron at a given distance r from (0,0,0). This one is 0 for r=0 also for s-electrons (the esteemed reader may work out why this is the case.

).

PS: I like the notion of "finding an electron".

* In theoretical applications density functions often are composed of Dirac delta functions. These are not real anymore and then you can indeed obtain an integral over a zero volume which is bigger than 0.

DJF90 - 13-5-2009 at 09:30

The radial distribution function for any s-orbital electron is not zero (quite close though) at the nucleus, but neither is the maxima at the nucleus.

http://winter.group.shef.ac.uk/orbitron/AOs/1s/radial-dist.h...

watson.fawkes - 13-5-2009 at 09:56

Quote: Originally posted by DJF90

The radial distribution function for any s-orbital electron is not zero [...]

Oops. The wave function for a 1s electron has a maximum, but the probability density doesn't. Sorry.

turd - 13-5-2009 at 10:22

Quote: Originally posted by DJF90

The radial distribution function for any s-orbital electron is not zero (quite close though) at the nucleus, but neither is the maxima at the nucleus.

http://winter.group.shef.ac.uk/orbitron/AOs/1s/radial-dist.h...

Note that I didn't say "at the nucleus", I said at r=0. Now read the link you posted: For s-orbitals, the radial distribution function is given by multiplying the electron density by 4*pi*r^2. The _radial_ distribution function _must_ be 0 at r=0. Just think about it for a minute.

Quote:

The radial distribution function for any s-orbital electron is not zero [...]
Oops. The wave function for a 1s electron has a maximum, but the probability density doesn't. Sorry.

Oh, now I'm dissapointed, watson. You were right before.

Think about how the wave function and the probability density are related. Of course the probability density function has a maximum at (x,y,z)=(0,0,0). That's the most probable place you'll find an electron at.
The _radial_ probability function is something completely different: it tells you at which _distance_ from the core an electron is most likely to be found. This must be 0 for r=0. Think about the ratio of the surface of a sphere with r=0 and with r>0 then this should be immediately obvious.

Check this out: http://en.wikipedia.org/wiki/Conditional_probability

watson.fawkes - 13-5-2009 at 10:32

Quote: Originally posted by turd

Oh, now I'm dissapointed, watson. You were right before.

yeah. I was a little hasty. For 1s electron, the spatial probability density has a maximum and the origin. The radial density does not (it's a local minimum).

len1 - 13-5-2009 at 15:14

There are many aspects observed then in atomic spectra that the semiclassical theory could not account for: fine structure due to relativistic effects, effects due to spin-orbit coupling, hyperfine splitting due to the spin of the nucleus, and the electron interactions. QM is able to account for all of these, although the last was very difficult to do accurately then because the three body problem in QM is not analytically solvable. You separate the last as having been the only aspect the known - have you any reference to this?

This argument about prob density function is a waste of time, the prob density for l=0 is ~ dV e^(-r/bohr radius) where if you assume spherical symmetry dV = 4 pi r^2 dr. The prob of finding the electron in a small volume is highest at the nucleus as turd says. To say its zero is to put dV=0 in above formula and so meaningless. I could do the integral r^2 e-() dr, or look it up in a book to get exact number, but its just a small multiplicative correction so why bother here.

While one cant test the atom for stability against radiation using just a QM treatment of Coulombs law, which is the ordinary SE, the exact solution for a two EM particle relativistic quantum system is a many body problem and so hard to do. One can assume stability through the fact that the orbital problem, being a time varying one in classical theory, is a static problem in quantum theory where the only information is a prob density dependent on potential. Since nothing is time varying there is no charge current and one doesnt expect to get radiation.

Magpie - 13-5-2009 at 15:32

Quote:

Since nothing is time varying there is no charge current and one doesnt expect to get radiation.

Len, does this imply that the electron is actually not a particle? And is certainly not a moving particle? If not, just what is an electron? What the QM math says it is?

watson.fawkes - 13-5-2009 at 17:06

Quote: Originally posted by len1

There are many aspects observed then in atomic spectra that the semiclassical theory could not account for: fine structure due to relativistic effects, effects due to spin-orbit coupling, hyperfine splitting due to the spin of the nucleus, and the electron interactions. QM is able to account for all of these, although the last was very difficult to do accurately then because the three body problem in QM is not analytically solvable. You separate the last as having been the only aspect the known - have you any reference to this?

I had hoped that, when I repeated what I had said, elaborating on it, by emphasizing that it was a historical account, that I had addressed the point sufficiently for you to understand it. Apparently not.

turd - 13-5-2009 at 21:04

Quote: Originally posted by len1

This argument about prob density function is a waste of time

Actually, I think it's useful! For the mathematically naive person it may seem contradictorily that on one hand the highest probability region of an electron is the origin, while on the other hand r=0 is the most unlikely distance from the origin you'll find an electron at. And this thread is proof that it really does confuse people. Once you understood that you learned a deal about probability and infinitesimal calculus.

Quote:

The radial density does not (it's a local minimum).

True, but you can formulate that in an even stronger way: the radial probability density function has a _global_ minimum at r=0. Because it has to be 0 for any real* probability distribution and that's the lowest density you can have. So for s-electrons r=0 is the most unlikely distance, but defines the most likely place.

* I mentioned Dirac deltas before.

len1 - 14-5-2009 at 01:52

Quote: Originally posted by Magpie

Quote:

Since nothing is time varying there is no charge current and one doesnt expect to get radiation.

Len, does this imply that the electron is actually not a particle? And is certainly not a moving particle? If not, just what is an electron? What the QM math says it is?

Hi Magpie, nice to hear from you again. Quantum mechanics says the electron is a particle but all its particles are also waves. The most standard approach in physics is 'feel your way as far as you can, then just do the maths because it works.' Schrodinger himself never accepted the way physicists use his equation, neither did Einsten. The former chanced up on an equation for a function whose meaning he struggled to glean, a short time later Bohm gave it its present meaning, on which all its subsequent success was based, and the former two spent most of their remaining lives protesting against it - in vain, they could propose no alternative, while quantum mechanics - Schrodinger's, as interpreted by Bohm, worked.

In classical mechanics its relatively easy

F = ma

which reduces to a simple second order differential equation for the motion of an electron (or the moon or the earth) about the centre of mass

K/|x|^2 = m d^2x/dt^2

You get all your planetary motion from there.

In the discussion on lenses in another thread I mentioned diffraction. If you shorten your apperature, your resolving power deteriorates. From the formula I gave there you get

aperature * angular resolution > constant

For light this is a mathematical consequence of its wave nature which can be got from Parsevals inequality - a purely mathematical result - the width of a distribution multiplied by the width of its Fourier transform is bound from below.

There was a lot of evidence in the early 20s that all problems with atomic spectra, stability of the atom, etc could be explained if this held for particles also. That is if you use electrons say instead of light in your camera (as in an electron microscope) you still have the same basic constraint.

After a lot of torturous trial and error maths Heisenberg arrived at

spread of momentum * spread of position > Planks constant

As a fundamental law of nature! More fundamental than F=ma - which then becomes untrue. This is because you can no longer talk of trajectories. When you say an electron is stationary or it is moving you mean there is a function, position as a function x(t). This would then give velocity as its derivative, and you would know the velocity and position exactly, in contradiction to the basic tenet of the world. So this answers your second question - its senseless to talk of the electron moving instanteneously since it has no trajectory, as for its mean location - quantum mechanics does not deny the existance of this, then we know the answer - its centre of mass is moving nowhere. So thats what quantum mechanics says - theres no motion, the problem is a static one, and so no radiation.

To calculate something Schrdonger used Hamiltons formulation of mechanics. This is an energy formulation. For the problem above you know electrostatics conserves energy so one can write the kinetic energy of the electron plus its potetntial energy in the electrostatic field is a constant

1/2 p^2/2m + k/r = constant

Which is just an integral of the second order equation and so in classical mechanics gives the same results. But quantum mechanics treats this as its basic equation - it is not derived from a law of motion, which according to quantum mechanics does not exist.

To get the particles position X(x) and momentum P(p) functions to satisfy the Heisenberg relation as a mathematical consequence, in the same way as for light, they must be Fourier transforms of each other. It follows from equating probabilities in both mometum and position that the momentum is a first order differential with respect to x, p ~ d/dx. So you get

-h^2 d^2/dx^2 X(x) + kX(x)/x = constant X(x)

which is Schrodingers original equation.

You prob wont get the last bit, I thought I could find an easier way when I started writing this. Once I got this far it seemes a pity to throw it away, so I post it.

@fawkes, dont know whats theres to get upset about. I asked for a reference to what you were saying. Schrodinger only mentioned the hydrogen atom in his paper, effects such as Zeeman, Stark, fine splitting etc. If you dont have a reference that the Helium spectrum was what was considered most convincing, fine.

[Edited on 14-5-2009 by len1]

Magpie - 14-5-2009 at 08:15

Thank you Len for that concise explanation. The lack of radiation loss of energy of "an electron" was always a stumbling block for me. I certainly don't understand it all but this explanation does advance my primitive grasp of the subject.

jgourlay - 14-5-2009 at 08:56

Wow....okay. Serves me right for asking impertinent questions!

Magpie - 14-5-2009 at 10:46

I don't think your question was impertinent - it is a very good question. It just doesn't have a simple answer.

len1 - 14-5-2009 at 16:32

Unfortunately for students of quantum physics this is only the easy part.

Schrodingers equation of 1926 is a wave theory of mechanical particles (of Newtons second law, to which it reduces as it must for large distances and masses, m x^2/t>>Plancks constant). But this constant came about twenty odd years earlier in a completely different problem - in Einstein giving particle characteristics to waves, that is light. So we now needed a particle theory of waves.

Dirac did this in 1927 by quantizing (doing a Schrodinger to) Maxwells equations which describe light, by giving the waves particle characteristics satisfying an uncertainty relation. Their wave characteristics were retained in the same way as Schrodingers particle waves have particle characteristics. Heisenberg was impressed by this enough to say he could never compete with it.

So Schrodingers equation describes wave particles (things that at large scales seem particles but at small scales are waves. Diracs quantization describes particle waves (things that at large scales seem waves but at small scales are particles), whose number is quantized. What about particle waves - why is their number not quantized?

At first this seems unnecessary since if you have two electrons say - they stay two electrons. But that is only at small energies. Relativity means particles can be created out of nothing - so the great blow is that if you combine the two you have an infinite number of particle theory without ever wishing for it.

A new round of quantization, called second quantization, was needed on Schrodingers particles, of which his equation turned out to be only an approximate - non quantized version.

The resulting theory - QFT had many problems - some still persist, cant be solved exactly, or even estimates of errors given. But its been successful, and is where we are today.

Incidently Schrodinger originally wanted to write a relativistic quantum equation. But saw that it immediately lead to an infinity of particles, infinite integrals, and put it away

[Edited on 15-5-2009 by len1]

woelen - 14-5-2009 at 22:55

Jgourlay, I think that the best answer to this question is not a matter of trying to explain the (incredibly complicated mathematics and physics) of (sub)atomic systems, but trying to explain somewhing about human intuition, which is based on human experience.

In daily life we observe the world in a certain way. Based on everyday observations, we build up an 'intuitive model' in our brains, and we use that model all the time implicitly (we do not actively perceive that we use it) to predict things and to understand things.

Our observations are limited to macroscopic observations at low speeds. All other things we NEVER see, and hence they are beyond our experience and for that reason beyond our imagination.

A nice example is our implicit model that velocities can be added linearly as 3D vectors. We use that model all the time (e.g. estimating whether it is safe to cross a street while a car is coming while at the same time you are driving a car on a street which crosses the other street). Imagine that you were living in a world where velocities always are in the order of 2/3 of lightspeed or even higher. Then you cannot add velocities anymore. The more general thing (in one dimension) is w = (u+v)/(1+uv/c^2), where w is the relative speed between two objects, moving at speeds u and v. For velocities u, v much smaller than c, this is VERY close to w = u+v and hence our intiutive model says that this is always the case. We would miserably fail in a world where velocities are much higher and we would be like babies again when we had to survive in such a world without having accidents all the time. A little child has to learn what is safe and what is not and we would have to learn that again in a world where ultra high-speed travel is normal.

A similar problem exists for the ultrasmall world, where particles are not well-determined objects, but fuzzy things, which can overlap without colliding and that kind of things. If we would see such things in our daily life all the time, then our 'intuitive model' would incorporate such things and we would have no problems with it, but because we never see such things in our daily life, they are very weird and counter-intuitive for us.

So, I would say to your son that for such very small particles the world looks totally different and that the things which we find normal do not apply in that world and that we are bad at handling and understanding this, simply because we never see anything from that world. You can also say that there is a language called 'mathematics' which describes such worlds, but that this language is not something we can see but only something which allows us to compute and predict things. The language gives us more abstract understanding, but not more intuitive understanding and that makes communication of these concepts to laymen so extremely hard.

[Edited on 15-5-09 by woelen]

len1 - 15-5-2009 at 02:30

The original question topic had exhausted itself when it received a simple answer at the start of the thread (yes, they do 'bump' into each other, but can not mutually annihilate). The rest of the thread has been about quantum mechanics.

kmno4 - 16-5-2009 at 09:29

Electron and proton cannot anihilate because e is not antiparticle for p (and vice versa).
There is simple path for joining proton and electron:
p+e -> n+neutrino(e)
Lepton and baryon numbers are conservated in this process.
It requires additional energy - it is easy to see it by comparing sum of masses of proton and electron with mass of neutron.
Of course, this is not the only way of p-e interacting at high and very high energies.
Hydrogen atom is the only "thing" made from p and e which is stable in our room temperature world

Besides - has not anybody heard about K-capture ??
It is evident example of electron capture by (proton in) nucleus.

[Edited on 16-5-2009 by kmno4]

len1 - 16-5-2009 at 16:40

Yes well here you go. Whats too complicated for someone is too simple for someone else.

Electrons can get captured by protons and all sorts of reactions conserving Baryon numbers are possible. BUT theres not enough energy in the hydrogen atom for these to be real processes - e- p+ is the lowest energy state. Nevertheless they all occur - virtually - in the atoms, and contribute an invisibly tiny correction to the mass of the hydrogen atom.

franklyn - 17-5-2009 at 16:59

"- if the negative electron and positive proton are attracted, how come the electron
acts like a planet around the sun? How come they don't bam into each other?"

Oh but they do, the result is a neutron. But you need a whole lot of gravity
to overcome the excess energy of the electron which serves as the referee
keeping them apart. An experiment to show this would be to try to stick
two magnets together ( poles opposing so that they repell ) using double
sided adhesive tape. Good luck.
A neuron free of an atom or neutron star will decay in about 905 seconds,
on average, turning back into a proton and electron. Its important to realize
that a neutron does not contain a proton or electron, those are just it's
decay products. The Bohr model of the atom ( solar system analog ) is a useful
mnemonic fiction to keep things organized in thought and do not realistically
represent atomic objects. Particles are just organizations of energy, sort of like
a holler, a gunshot, or a violin tone. When you hear them all together do they
bam into each other ?

Particles actually refuse to be pinned down in any defined place and time, and
are forever in a transitional state between being over here and somewhere else
over there. Uncertainty is a fundament of reality.
When you flip a coin you do not know what the result will be except it can be
either the head or the tail . If you do know what a result will be ( because you
have chosen a result as you do in a wager ) then you do not know when this will
occur, it may be the first flip or not, second or third and so on until the chosen
result is seen. You can know when there will be a result ( most of the time ) but
you will not know what the result will be, or else you can know the result, you
just won't know when it will occur. It is impossible to know both together.
If you could then you would be master of space and time and pantocrator
of the universe - sort of like an investment banker, reality notwithstanding.

This would raise other troubling questions such that you can only really
know of a future event if in some sense it already exits. That would
circumscribe free will to a notional illusion where everything plays out
its role, part, or function as if it were a wind up toy in a movie, one
cannot do otherwise, even contemplate the idea unless it is already
on the film to be played out.

Anyway one must not simpify too much, if the answer to a question
becomes too simple, you might become a Noble Laureate.

P.S.
A wise man , Jacob Bronowski , once said :
" ask an impertinent question , and you are on your way to the pertinent answer. "

Quote: Originally posted by jgourlay

Wow....okay. Serves me right for asking impertinent questions!

[author=Magpie]I don't think your question was impertinent - it is a very good question. It just doesn't have a simple answer.

useful sites
http://web.jjay.cuny.edu/~acarpi/NSC/3-atoms.htm
http://www.colorado.edu/UCB/AcademicAffairs/ArtsSciences/phy...
HERE IS THE RESOURCE
http://www.colorado.edu/UCB/AcademicAffairs/ArtsSciences/phy...
Click " Electron Orbits " it's this one below
http://www.colorado.edu/UCB/AcademicAffairs/ArtsSciences/phy...
Move the mouse SLIGHTLY as you click the empty space surrounding the red " proton " to create the
electron and give it a lateral motion. Left or right it doesn't matter. It does get crowded after a few.
DeBroglie Wave concept is also useful - Click on the circumference of the circle and drag to change diameter
http://www.colorado.edu/UCB/AcademicAffairs/ArtsSciences/phy...

franklyn - 23-5-2009 at 08:11

A neat summatiion of contemporary field and particle physics
- A T O M - Illusion of Reality
http://www.ninjavideo.net/video/8752

click " Download " at the upper left of the view screen
to download the whole file or else watch it in your browser instead.
This is a huge 550 MB high definition avi video
You may need to first install Ninja video's java applet, I don't know.

.

franklyn - 2-6-2010 at 00:25

U P D A T E

- A T O M - Illusion of Reality
http://video.google.com/videoplay?docid=-1406370011028154810...

.

zed - 2-6-2010 at 06:23

We don't know what electrons and protons really are. We know they like each other, and they like to be close, but not too close. Not unlike your mommy and daddy.

This is a good thing. If the proton and the electron melded together....The Universe as we know it, would cease exist. Just like our family would cease to exist, if mommy and daddy were confined together for a long time in a very small space. Like this house.

That is why....You are going to clean your room, and I am going to mow the lawn. And then, the two of us are going fishing.....While your mom does whatever it is she does, when she isn't burdened by our presence.

[Edited on 2-6-2010 by zed]

Rich_Insane - 3-6-2010 at 08:36

I'm no expert on quantum mechanics, but here's my $0.02

The electrons orbit far away from the nucleus at very high speeds. Now think about riding a bike. The reason you don't tip over when you turn the street is because you are going so fast that that force is keeping you up against gravity. Now back to the electron. it is moving in a random orbit at enormous speeds in its shell. The attraction to the proton is kind of like gravity. That speed allows the electron to move around so fast that it overcomes the attractive forces between + and -.

Again, that's just my idea.

reply to your ques

jaisachdeva - 4-6-2010 at 11:26

I think suggest you to put two ball in a transparent plastic cup and seal the top of cup using a similar inverted cup by taping the two, then rotate the model, balls will stick to walls. Tell the child that force due to which balls are sent outwards is cancelled by normal reaction from the cup base and which can be assumed to be as the attractive force of between proton and electron.

lol - 28-7-2010 at 04:45

they arent attracted...they basically float in space as the proton expands and pushes them out

Hoveland - 28-7-2010 at 17:01

The truth is that scientists do not really know the answer. They have equations to describe particle interactions, and these equations describe two unsymetric waves that do not annhilate eachother.

More complex, is some speculation by physicists that the subatomic particles are themselves composed yet smaller point-like constituents, which for a variety of reasons cannot be freed from their subatomic particles. The existence of quarks is already accepted theory, but more controversial is the theory that electrons are composed of 2 or 3 smaller constituents. Some of this is relative of course. In particle colliders at extremely high energies, electrons have smashed into X-rays, revealing a quark substructure inside the photon.
From the point of reference of the electron, the photon is the only particle that is moving, and it is a photon, it is greatly blue-shifted, so much so that it has the (relative) mass of a proton. The uncertainty principle, in this case, allows high probability of finding quarks. High frequency translates into high rest-mass particles. This, of course, is not implying that photons actually contain quarks, just that energy and matter is very interchangeable. Many physicists suspect a microstructure for photons, that would explain spin and polarization (did you know photons can be circularly and elliptically polarized, as well as have a separate property of angular momentum, which comes in quanta (hbar) ?
http://www.icfo.es/index.php?section=research4&lang=engl...

Another bit of insight, it may be that there can never be any true annhilation into nothingness, because any sudden point of zero energy would "cut the string" - the particle's path through space and time. The string is theorized to snap back like a rubber band, leaving only the continuous strings left to exist in our present space and time.

[Edited on 29-7-2010 by Hoveland]

psychokinetic - 28-7-2010 at 23:21

Quote: Originally posted by lol

they arent attracted...they basically float in space as the proton expands and pushes them out

Whoops, all my electrons fell off.

len1 - 28-7-2010 at 23:44

Good to see they now have internet access in the mental hospital

lol - 29-7-2010 at 06:34

psychokinetic - 29-7-2010 at 21:45

Because they're married.

len1 - 29-7-2010 at 23:50

Because they are not married and catholic I think you meant

psychokinetic - 30-7-2010 at 13:52

Maybe that's where neutrinos come from.

peach - 4-8-2010 at 15:54

Quote: Originally posted by watson.fawkes

The thing to teach is that models are approximations to reality, not generators of reality, and that every model has some non-universal realm of applicability.

You would not believe the amount of time I had to spend, unsuccessfully, trying to explain that concept to my older brother (who would most definitely claim to be scientifically, Dawkins oriented (ironically brainwashed into belief)) when trying to discuss the idea of how higher deminsional spaces predict and then explain interactions at the quantum level.

"But has someone actually BEEN to these dimensions yet!?"
"That's NOT the point..."

I tried multiple methods. There are some people who don't seem to 'get' the idea that it's not necessarily a solid, tangible thing that exists in reality, merely that 'reality' behaves in a similar way and can be described by the models.

There are others, often the mathematically minded, who excel at this way of thinking. Electronics engineers work with what are essentially black box (tiny, tiny, tiny black boxes), where one thing goes in one side and something else comes out the other. There is clearly a very different mindset at work.

I ended up giving him a book on superstring theory as he stormed out of the room. What confused me about my brother is his firm belief in things like evolution and standard nuclear physics, yet inability to take a not very large step beyond that to quantum mechanics and the string model (and no, he doesn't know about alternatives like super gravitational field theory, so that's not why).

I tried pointing out that this maths has not only predicted the groups of quantum particles, but the missing ones as well, which have then been found and then explained using the same rules. I also tried likening this to the more basic laws of physics which model kinetic behaviours at the tangible level. Or the way Mendeleev left spaces for elements we've now found (darn smarty old chap). I said clearly, many times, that they may not actually be places you can go to, just that they're required by the maths that predicts the interactions in the lower dimensions.

The two never joined up.

I used to be a millitant athetist. Then realized, I could churn out any shit I felt like and say it was quantum mechanics and easily convince a lot of atheists it was correct, due to their own belief that anything sounding scientific nowadays is the utter truth. Which is the point where I began to take sides with the religious, if only to duly annoy the atheists. Indeed, they believe so even more than I. When I read a journal or model, I start off assuming it's incorrect, then wait for it to prove it's self correct; an unfortunately pessimistic view on things, but one that means your mobile phone works. A worrying majority of people now assume it's all correct, to the degree of expecting models to be solid, tangible objects. Then they have an episode when it goes beyond that, and is proving it's self to be correct; like higher dimensional (ethereal other domain) string theory.

In my brother's case, he routinely goes on about how his job is harder than anyone else's (as everyone does, even porn stars). He hates the idea of someone knowing something he doesn't. Which I suspect is the grounds for his hatred of the idea of higher dimensional models that hint at something beyond the Dawkinesque, solid way of life.

[Edited on 4-8-2010 by peach]

watson.fawkes - 5-8-2010 at 06:26

Quote: Originally posted by peach

"But has someone actually BEEN to these dimensions yet!?"
"That's NOT the point..."

I've been there. I go there all the time. I travel there with my imagination.