# The Naked Scientists Forum

### Author Topic: How big is an electron if we measure its force field?  (Read 3612 times)

#### jccc

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##### How big is an electron if we measure its force field?
« on: 16/05/2015 20:53:18 »
suppose we can measure the force between 2 electrons light year apart, can we assume electron has a light year radius?

what if we can measure any amount of force? is force liner?

i had a feeling, box and i experienced most headaches thinking science. for we are slower.

#### jccc

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##### Re: How big is an electron if we measure its force field?
« Reply #1 on: 17/05/2015 05:46:20 »
if i am an electron
every where i reach is space
every charge i feel is friend
my arms are too long
i love protons
they will hold me tight
i hate electrons
they always push me around
there's 1 thing i don't understand
why God made those tiny tiny baby trons
i hate them more than anything
i haven't had any since day 1
cus protons love them more

#### jccc

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##### Re: How big is an electron if we measure its force field?
« Reply #2 on: 23/05/2015 13:23:53 »

no wiki? no thought? no opinion?

must be a dumb question.

how do you think Box?

#### Thebox

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##### Re: How big is an electron if we measure its force field?
« Reply #3 on: 23/05/2015 13:42:14 »

no wiki? no thought? no opinion?

must be a dumb question.

how do you think Box?

I think the radius is variable

#### jccc

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##### Re: How big is an electron if we measure its force field?
« Reply #4 on: 23/05/2015 14:54:43 »
please be precise, science is not politic.

#### julrich

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##### Re: How big is an electron if we measure its force field?
« Reply #5 on: 29/05/2015 04:11:37 »
F = k (q1q2) / r2

F = (9 x 109 N) (1.60217657×10-19 C)2 / 9.46x1015m

F = 2.44x10-44 N of electrostatic force between two electrons with a radius of 1 light year.

#### chiralSPO

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##### Re: How big is an electron if we measure its force field?
« Reply #6 on: 29/05/2015 04:31:12 »
The Earth exerts a gravitational field that is non-zero at a distance of a light year, does that mean the Earth is a light year big?

#### PmbPhy

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##### Re: How big is an electron if we measure its force field?
« Reply #7 on: 29/05/2015 08:44:24 »
Quote from: jccc
suppose we can measure the force between 2 electrons light year apart, can we assume electron has a light year radius?
No. Of course not. What led you to such a crazy notion? First of all the electron has zero radius. The force exerted by one electron by another is determined solely by the distance between them (since the charge on an electron is a fixed and given quantity).

Quote from: jccc
what if we can measure any amount of force? is force liner?
No. Most forces aren't linear. (once again you have yet another spelling error. It's "linear" not "liner").

#### jccc

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##### Re: How big is an electron if we measure its force field?
« Reply #8 on: 29/05/2015 09:57:51 »
Quote from: jccc
suppose we can measure the force between 2 electrons light year apart, can we assume electron has a light year radius?
No. Of course not. What led you to such a crazy notion? First of all the electron has zero radius. The force exerted by one electron by another is determined solely by the distance between them (since the charge on an electron is a fixed and given quantity).

Quote from: jccc
what if we can measure any amount of force? is force liner?
No. Most forces aren't linear. (once again you have yet another spelling error. It's "linear" not "liner").

if electron has zero radius, it should not occupy space, how could a photon hit an electron?

the distance between charged particles is linear, f=ke x q1q2/r^2, therefore force is linear?

#### PmbPhy

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##### Re: How big is an electron if we measure its force field?
« Reply #9 on: 29/05/2015 10:25:32 »
Quote from: jccc
if electron has zero radius, it should not occupy space, how could a photon hit an electron?
Here we have you yet once again thinking of quantum particles using classical notions. Electrons and photons aren't classical particles, they're quantum mechanical ones. To understand scattering cross sections for photons and electrons you'd have to study particle physics and/or quantum field theory. I haven't gotten around to that yet but I contacted a friend and asked him for the QM explanation and am awaiting his response.

Quote from: jccc
the distance between charged particles is linear, f=ke x q1q2/r^2, therefore force is linear?
Nonsense yet again. A force is linear if the magnitude of the force is proportional to distance. For example; the gravitational force of a particle in a uniform gravitational field is F = -mgz. This force is linear. However f=kq1q2/r2  is not linear because the magnitude of the force is not proportional to distance.

#### PmbPhy

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##### Re: How big is an electron if we measure its force field?
« Reply #10 on: 30/05/2015 02:58:26 »
Quote from: jccc
if electron has zero radius, it should not occupy space, how could a photon hit an electron?
I did some digging and found the answer. As I said, you keep thinking in terms of classical particles whereas photons and electrons are quantum mechanical particles so the impressions like this that you use are totally wrong. The answer lies in what's known as a scattering cross section. The Klein–Nishina formula gives the differential cross section of photons scattered from a single free electron in lowest order of quantum electrodynamics. A differential cross section is a scalar that only quantifies the intrinsic rate of an event.

http://en.wikipedia.org/wiki/Klein%E2%80%93Nishina_formula
http://en.wikipedia.org/wiki/Cross_section_(physics)#Differential_cross_section

After all this time that we've all suggested reading a book on physics have you ever seriously considered following those suggestions even a little bit?

#### jeffreyH

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##### Re: How big is an electron if we measure its force field?
« Reply #11 on: 01/06/2015 01:24:43 »
Quote from: jccc
if electron has zero radius, it should not occupy space, how could a photon hit an electron?
I did some digging and found the answer. As I said, you keep thinking in terms of classical particles whereas photons and electrons are quantum mechanical particles so the impressions like this that you use are totally wrong. The answer lies in what's known as a scattering cross section. The Klein–Nishina formula gives the differential cross section of photons scattered from a single free electron in lowest order of quantum electrodynamics. A differential cross section is a scalar that only quantifies the intrinsic rate of an event.

http://en.wikipedia.org/wiki/Klein%E2%80%93Nishina_formula
http://en.wikipedia.org/wiki/Cross_section_(physics)#Differential_cross_section

After all this time that we've all suggested reading a book on physics have you ever seriously considered following those suggestions even a little bit?

#### PmbPhy

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##### Re: How big is an electron if we measure its force field?
« Reply #12 on: 01/06/2015 02:22:51 »
Quote from: jeffreyH
Absolutely not. I don't expect him to understand it at all. My point is that some things are so far over his head that he has no hope of understanding it so he shouldn't bother trying unless he learns physics. Since that's never going to happen he should just give it up.

#### alancalverd

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##### Re: How big is an electron if we measure its force field?
« Reply #13 on: 01/06/2015 11:16:31 »
First of all the electron has zero radius.

Ummm....well.....the classical model is a point charge but we know the electron has mass, angular momentum, and a magnetic moment, so we can define something analogous to a radius even though the classical equations give us the wrong answer.

If you have a lifetime to spare, you could introduce jccc to quantum electrodynamics, but you would probably have more fun poking your eye out with a stick - it would certainly be about as productive.

#### PmbPhy

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##### Re: How big is an electron if we measure its force field?
« Reply #14 on: 02/06/2015 08:24:33 »
Quote from: alancalverd
Ummm....well.....the classical model is a point charge but we know the electron has mass, angular momentum, and a magnetic moment, so we can define something analogous to a radius even though the classical equations give us the wrong answer.
Saying things like that will always lead people to wrong ideas. If the electron had a non-zero radius then there'd be problems with that. I forget what they are but I do recall reading and following the arguments to their conclusions. Fritz Rohrlich discusses this in his text "Classical Charged Particles".

#### jccc

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##### Re: How big is an electron if we measure its force field?
« Reply #15 on: 02/06/2015 13:34:46 »
problems like:

why electron and proton not contact?

is hydrogen atom 2 d or 3 d?

how electrons move relate to the nucleus?

why no discharge within atoms?

why atoms are not compressible?

wiki nothing, book nothing, still wonder.

can someone help, give answers that are understandable.

#### chiralSPO

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##### Re: How big is an electron if we measure its force field?
« Reply #16 on: 02/06/2015 15:23:07 »
why electron and proton not contact?
they do contact--it's called an atom. Why do they not combine to form neutrons? Because atoms are more stable unless there is a lot of pressure forcing them to combine into neutrons (like in a neutron star)

is hydrogen atom 2 d or 3 d?
atoms are definitely 3D, think of them as spherical.

how electrons move relate to the nucleus?
concepts like motion don't work well on (sub)atomic scale

why no discharge within atoms?
there is no way for an atom to discharge within itself

why atoms are not compressible?
they are compressible

#### jccc

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##### Re: How big is an electron if we measure its force field?
« Reply #17 on: 02/06/2015 15:32:22 »
is this science or politic?

how electron and proton contact?

is electron circling or not?

how can 1 electron circling 1 proton to form 3 d hydrogen atom? isn't orbits are 2 d?

why is micro world is so strange? because we can not see it clear?

#### alancalverd

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##### Re: How big is an electron if we measure its force field?
« Reply #18 on: 02/06/2015 20:11:59 »
is this science or politic?

science, at least as far as I am concerned.

Quote
how electron and proton contact?

they don't

Quote
is electron circling or not?

no

Quote
how can 1 electron circling 1 proton to form 3 d hydrogen atom? isn't orbits are 2 d?

irrelevant model

Quote
why is micro world is so strange? because we can not see it clear?

nothing strange about it - it's happening all the time, everywhere. It's just that the mathematics that describes very small things and very big things is more complicated than the mathematics of everyday things. But there's no mystery: quantum physics turns into classical physics when you add it up over huge numbers of particles, and relativity turns into classical mechanics at low speeds.

#### jccc

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##### Re: How big is an electron if we measure its force field?
« Reply #19 on: 03/06/2015 14:21:09 »
if electron is not bigger than my head, why is my headache?

why is electrons flirt around never hit the target? is any force stronger than the attraction force between electron and proton in the whole universe?

if electron is not circling, there would be no centrifugal force, electron should falling down to proton?

what is correct model for a hydrogen atom?

isn't in micro world, newton's law not working? coulomb's law not working?

#### chiralSPO

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##### Re: How big is an electron if we measure its force field?
« Reply #20 on: 03/06/2015 16:34:46 »
Simple fact: if you put something in water it gets wet.

Simple question: if you put an electron in water does it get wet?

Ponder this a while and then think about your other questions in the same way. I will give hints if you (jccc) ask for them.

#### jccc

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##### Re: How big is an electron if we measure its force field?
« Reply #21 on: 03/06/2015 17:20:13 »
well, let's get wet together.

please tell the secret of atomic structure.

#### alancalverd

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##### Re: How big is an electron if we measure its force field?
« Reply #22 on: 03/06/2015 23:34:16 »
isn't in micro world, newton's law not working? coulomb's law not working?

Scientific laws are nothing more than mathematical approximations to observations. There's no question of "laws not working" - it just happens that when you look closely at something, the behaviour is often more complicated than it seems at a distance.

#### jccc

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##### Re: How big is an electron if we measure its force field?
« Reply #23 on: 05/06/2015 17:53:49 »
everything has its unique mechanism. all physics laws must be obeyed.

science is precise description of reality. micro world is the same, no magic, no mystery.

if anyone really understood atomic structure, please come forward.

it is ok to say i am not sure about it. we are learning all the time.

#### jccc

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##### Re: How big is an electron if we measure its force field?
« Reply #24 on: 05/06/2015 21:12:08 »
without other force, 2 masses at r distance will attract each other and come closer and impact.

same way for 2 opposite charges, such as proton and electron in atoms.

electron able to obit is a mystery not yet answered.

we have all kinds of high tech toys, not yet a working model of a hydrogen atom. what a surprise?

#### The Naked Scientists Forum

##### Re: How big is an electron if we measure its force field?
« Reply #24 on: 05/06/2015 21:12:08 »