The Naked Scientists

The Naked Scientists Forum

Author Topic: The Discovery of the Neutron or is it?  (Read 7628 times)

Offline mathew_orman

  • Sr. Member
  • ****
  • Posts: 132
    • View Profile
The Discovery of the Neutron or is it?
« on: 05/10/2015 09:54:23 »
http://dev.physicslab.org/Document.aspx?doctype=3&filename=AtomicNuclear_ChadwickNeutron.xml

Geiger counter does not detect electrons then why would it detect protons?
Did Chadwick tried exposing paraffin discreetly to Polonium radiation and comparing the results?
Would Chadwick interpret the results not in favor to Rutherford's hypothetical Nucleus?


 

Offline evan_au

  • Neilep Level Member
  • ******
  • Posts: 4113
  • Thanked: 245 times
    • View Profile
Re: The Discovery of the Neutron or is it?
« Reply #1 on: 05/10/2015 11:25:28 »
Quote from: mathew_orman
Geiger counter does not detect electrons then why would it detect protons?
The Geiger Counter is built around a gas tube containing a high-voltage wire, which will spark over if a conductive path appears in the gas. The spark produces the familiar "click", and can be used to drive an analog or digital indicator.

This device is able to detect Beta particles (electrons or positrons), alpha particles and protons, as these are electrically charged, and will leave a trail of conductive ions in their tracks.

Neutrons, being neutral, don't leave much of an ionized trail behind them (nor do the neutral gamma rays). So you need some material in between the source and the sensor to generate charged particles that can be detected by the Geiger counter.

Quote
Would Chadwick interpret the results not in favor to Rutherford's hypothetical Nucleus?
Rutherford assumed that there were electrons & protons together, making up the observed mass of the nucleus. But electrons and protons were knocked out of a nucleus, the Geiger counter should detect them.

The Geiger counter did not detect protons & electrons directly, so the mass of the nucleus must be made up of a new, neutral particle, which came to be called the neutron.

Note: This sounds a bit like a homework assignment. We are not here to do your homework, but if you post your answer, we can point to some more resources to help you.
 

Offline mathew_orman

  • Sr. Member
  • ****
  • Posts: 132
    • View Profile
Re: The Discovery of the Neutron or is it?
« Reply #2 on: 05/10/2015 12:31:55 »
Geiger–Müller tube does not detect electrons then again how would it detect hypothetical protons?
 

Offline mathew_orman

  • Sr. Member
  • ****
  • Posts: 132
    • View Profile
Re: The Discovery of the Neutron or is it?
« Reply #3 on: 05/10/2015 12:36:34 »
Also, how would a positive charged hypothetical proton escape sea of valence electrons in paraffin molecular structure of atoms?
 

Offline alancalverd

  • Global Moderator
  • Neilep Level Member
  • *****
  • Posts: 4704
  • Thanked: 153 times
  • life is too short to drink instant coffee
    • View Profile
Re: The Discovery of the Neutron or is it?
« Reply #4 on: 05/10/2015 13:27:39 »
Geiger–Müller tube does not detect electrons

All but one of mine do. What's wrong with yours? Try using a thinner window.
 

Offline mathew_orman

  • Sr. Member
  • ****
  • Posts: 132
    • View Profile
Re: The Discovery of the Neutron or is it?
« Reply #5 on: 05/10/2015 14:59:48 »
Geiger–Müller tube does not detect electrons

All but one of mine do. What's wrong with yours? Try using a thinner window.
What is the source of electrons and how far away from the window?
 

Offline alancalverd

  • Global Moderator
  • Neilep Level Member
  • *****
  • Posts: 4704
  • Thanked: 153 times
  • life is too short to drink instant coffee
    • View Profile
Re: The Discovery of the Neutron or is it?
« Reply #6 on: 05/10/2015 15:20:06 »
I use a militarised thin-window geiger (RamGene) for detecting surface contamination at about 2 cm separation. It is calibrated for beta radiation from 150 keV to 2 MeV but will indicate the presence of lower energy betas. More sophisticated devices will respond reasonably linearly below 30 keV.

You will have problems at more than 2 m separation because pretty much all electron radiation is absorbed by 2m of air.

Detection of alpha or proton radiation is more of a black art - air and window absorption is very strong. But as far as the geiger-muller mechanism is concerned, any ionising radiation that can get into the chamber will generate a pulse.

The weasel word in the article you quote is "easily". What may have been easy for Irene Curie after a lifetime in the best-equipped laboratory of its time, may not work convincingly on a kitchen table with a eBay geiger counter!
« Last Edit: 05/10/2015 15:28:11 by alancalverd »
 

Offline evan_au

  • Neilep Level Member
  • ******
  • Posts: 4113
  • Thanked: 245 times
    • View Profile
Re: The Discovery of the Neutron or is it?
« Reply #7 on: 05/10/2015 21:24:19 »
Quote from: mathew_orman
hypothetical proton
Protons were scientifically accepted by 1920, well before neutrons around 1930.

So protons were not hypothetical in 1930, and certainly are not hypothetical today, since they play a vital role in any chemical reactions involving acids, and many reactions involving water as a solvent, including those that keep you alive.

Quote
Also, how would a positive charged hypothetical proton escape sea of valence electrons in paraffin molecular structure of atoms?
The main decay product of Polonium is alpha particles, with an energy of around 5 Million eV.

When these alpha particles ("atomic mass" 4) collided with elements like Beryllium (atomic mass 9) and Lithium (atomic mass 7), they shook loose a previously-unknown form of radiation. Assuming the energy of the collision is shared approximately equally between the products of the collision, you could expect the resulting neutrons would have had an energy frequently exceeding 2 Million eV.

When these neutrons strike a hydrogen nucleus (proton), they have almost the same mass as the proton. Assuming the energy is again roughly shared between the resulting neutron and proton, it would impart around 1 Million eV to the proton.

The energy holding an electron and a proton together is only 13.6 eV, so the neutron has ample energy to knock a proton right out of a hydrogen atom.

Quote
escape sea of valence electrons?
The "sea" of electrons is balanced by a "sea" of protons in other hydrogen atoms, so the proton struck by the neutron really only has to escape from 1 electron.
 

Offline Colin2B

  • Global Moderator
  • Neilep Level Member
  • *****
  • Posts: 1915
  • Thanked: 123 times
    • View Profile
Re: The Discovery of the Neutron or is it?
« Reply #8 on: 05/10/2015 23:47:09 »
I use a militarised thin-window geiger (RamGene) ...
I held off answering this one as it has been a while since I used a Geiger counter and I was sure your info would be more upto date.
Also, I knew we could count on you to give a scintillating response.
 

Offline mathew_orman

  • Sr. Member
  • ****
  • Posts: 132
    • View Profile
Re: The Discovery of the Neutron or is it?
« Reply #9 on: 06/10/2015 08:21:34 »
This argumentation share my point of view on the hypothetical nucleus but the author's own theories are ridicules...
http://www.reciprocalsystem.com/cana/cana02.htm

Should I believe in logical reasoning or in what Wiki claims?
 

Offline alancalverd

  • Global Moderator
  • Neilep Level Member
  • *****
  • Posts: 4704
  • Thanked: 153 times
  • life is too short to drink instant coffee
    • View Profile
Re: The Discovery of the Neutron or is it?
« Reply #10 on: 06/10/2015 09:17:12 »
Quote
In this case the observed facts are entirely consistent with the hypothesis that most of the mass of the atom is concentrated in a very small region, to be sure, but they are equally consistent with the hypothesis that all of the mass is concentrated in this region; in other words, that this is the atom, not the nucleus of the atom.

Poppycock.

The electron has mass, and the effective diameter of an atom is a lot bigger than that of the nucleus (otherwise solids would be as dense as their nuclei), so we must conclude that some part of it is not concentrated in the nucleus. The predictability of ionic and covalent bonding supports the orbital wave function model.

Believe only what can be demonstrated by experiment. It's the key to staying alive, sane and happy.
 

Offline mathew_orman

  • Sr. Member
  • ****
  • Posts: 132
    • View Profile
Re: The Discovery of the Neutron or is it?
« Reply #11 on: 06/10/2015 10:51:18 »
You are quoting assumptions... Logical analyses of the events returns false... The nuclear model of an atom is unstable and orbital movements of electrons are not possible in such model because the hypothetical strong force...
To this date no simulation of such atom model is possible...
 

Offline mathew_orman

  • Sr. Member
  • ****
  • Posts: 132
    • View Profile
Re: The Discovery of the Neutron or is it?
« Reply #12 on: 06/10/2015 11:06:51 »
Most of all based on example of Hydrogen atom one electron will not prevent nucleolus to bind together due to the strong force...
The Hydrogen atoms would collapse up on intersection...
 

Offline alancalverd

  • Global Moderator
  • Neilep Level Member
  • *****
  • Posts: 4704
  • Thanked: 153 times
  • life is too short to drink instant coffee
    • View Profile
Re: The Discovery of the Neutron or is it?
« Reply #13 on: 06/10/2015 11:50:55 »
Having measured the mass of an electron (it's a classic undergraduate experiment) and the size and shape of many ions and molecules (ah, the joys of x-ray crystallography), I assure you that there are no assumptions in my statement.

If your model of an atom is unstable, abandon the model. Always start with reality, not logic, or you will end up looking as foolish as Aristotle or Pope Urban VIII.

The strong force is mediated by particles that do not operate outsdie the nucleus.

As your original opening statement was demonstrably untrue, I suggest you review all your sources of informaton.
« Last Edit: 06/10/2015 11:52:29 by alancalverd »
 

Offline mathew_orman

  • Sr. Member
  • ****
  • Posts: 132
    • View Profile
Re: The Discovery of the Neutron or is it?
« Reply #14 on: 06/10/2015 13:01:54 »
It is not my model which fails here...
It is fantasy wishful thinking assuming that electron will orbit a nucleus in Hydrogen atom...
Simple simulation shows that even if the electron is placed on a orbit then any external force however small will  make it ether fly away or bind to the hypothetical nucleus...
 

Offline PmbPhy

  • Neilep Level Member
  • ******
  • Posts: 2760
  • Thanked: 38 times
    • View Profile
Re: The Discovery of the Neutron or is it?
« Reply #15 on: 06/10/2015 13:38:27 »
Quote from: mathew_orman
http://dev.physicslab.org/Document.aspx?doctype=3&filename=AtomicNuclear_ChadwickNeutron.xml

Geiger counter does not detect electrons then why would it detect protons?
That's where you're wrong. See: https://en.wikipedia.org/wiki/Geiger_counter
Quote
The Geiger counter, is an instrument used for measuring ionizing radiation used widely in such applications as radiation dosimetry, radiological protection, experimental physics and the nuclear industry.

It detects ionizing radiation such as alpha particles, beta particles and gamma rays using the ionization effect produced in a Geiger–Müller tube; which gives its name to the instrument. [1] In wide and prominent use as a hand-held radiation survey instrument, it is perhaps one of the world's best-known radiation detection instruments.
 

Online chiralSPO

  • Global Moderator
  • Neilep Level Member
  • *****
  • Posts: 1874
  • Thanked: 143 times
    • View Profile
Re: The Discovery of the Neutron or is it?
« Reply #16 on: 06/10/2015 14:11:13 »
It is not my model which fails here...
It is fantasy wishful thinking assuming that electron will orbit a nucleus in Hydrogen atom...
Simple simulation shows that even if the electron is placed on a orbit then any external force however small will  make it ether fly away or bind to the hypothetical nucleus...

It sounds like your simulations are too simple then, or your model is built on poor assumptions. Remember that the physics and logic regarding subatomic particles on an atomic scale are very different from what appears to be true on a macroscopic level.

Electrons are effectively the size of the atom, and cannot get any closer to the nucleus (the electrons in an atom are already centered on the nucleus, and only with huge forces can an atom be compressed such that the electrons are more localized closer to the nucleus.

Electrons can be knocked out of their atoms with energies between 1–100000 eV (depending on the nucleus and energy level of the electron involved), but it is not a continuous process (ie electron "orbitals" cannot decay--the electron is in one state or another, and never between.
 

Offline mathew_orman

  • Sr. Member
  • ****
  • Posts: 132
    • View Profile
Re: The Discovery of the Neutron or is it?
« Reply #17 on: 06/10/2015 14:24:46 »
and cannot get any closer to the nucleus
What force will prevent that?
Also, there is only one logic of continuity of motion regardless of size scale...
 

Offline alancalverd

  • Global Moderator
  • Neilep Level Member
  • *****
  • Posts: 4704
  • Thanked: 153 times
  • life is too short to drink instant coffee
    • View Profile
Re: The Discovery of the Neutron or is it?
« Reply #18 on: 06/10/2015 14:33:11 »

It is fantasy wishful thinking assuming that electron will orbit a nucleus in Hydrogen atom...


Which is why nobody has used that model for the last 90 years. The valence shell model, a development of the Bohr atom, is adequate for most inorganic chemistry and for categorising spectra, but the quantum orbital model is necessary for stereochemistry.

Alas, the "logic of continuity of motion" is an intellectual vanity, not an observed property of atomic physics. Vanity is dangerous. 
 

Offline mathew_orman

  • Sr. Member
  • ****
  • Posts: 132
    • View Profile
Re: The Discovery of the Neutron or is it?
« Reply #19 on: 06/10/2015 14:39:29 »

It is fantasy wishful thinking assuming that electron will orbit a nucleus in Hydrogen atom...


Which is why nobody has used that model for the last 90 years. The valence shell model, a development of the Bohr atom, is adequate for most inorganic chemistry and for categorising spectra, but the quantum orbital model is necessary for stereochemistry.

Alas, the "logic of continuity of motion" is an intellectual vanity, not an observed property of atomic physics. Vanity is dangerous.
Well, please give an example  where a particle would vanish from current position and appear  in different location or change velocity and or position (jump) instantaneously...
« Last Edit: 06/10/2015 14:41:18 by mathew_orman »
 

Online chiralSPO

  • Global Moderator
  • Neilep Level Member
  • *****
  • Posts: 1874
  • Thanked: 143 times
    • View Profile
Re: The Discovery of the Neutron or is it?
« Reply #20 on: 06/10/2015 15:07:28 »
and cannot get any closer to the nucleus
What force will prevent that?
Also, there is only one logic of continuity of motion regardless of size scale...

No force required to prevent it. The nucleus and electrons in an atom all have the same center of mass—it is impossible for them to be any closer.

Then there is the question of the volume of the electron. Because the electron is much less massive than the nucleus (by at least a factor of 1836), it will naturally be more diffuse.

Yes, logic should be the same at any scale, but quantum logic is very complicated, and on large scales most of the complications cancel out, so we have learned a much simpler version of reality based on the observations of the collective motion of "objects" composed of 1000000000000000000000 particles.

For instance: you might say that it is a well-established, even proven, fact that water in a river flows downstream. This is true on average, so on a macroscopic scale you will never see this contradicted. However if one were to zoom in and look at the water on a molecular level, it would be obvious that all the molecules are moving randomly, with essentially a 50/50 chance of moving upstream or downstream (it is really something along the lines of 50.0000000000001/49.999999999999999999 and that slight bias on a molecular level is what accounts for our observations of the river.)
 

Offline alancalverd

  • Global Moderator
  • Neilep Level Member
  • *****
  • Posts: 4704
  • Thanked: 153 times
  • life is too short to drink instant coffee
    • View Profile
Re: The Discovery of the Neutron or is it?
« Reply #21 on: 06/10/2015 17:02:55 »

Well, please give an example  where a particle would vanish from current position and appear  in different location or change velocity and or position (jump) instantaneously...


The emission and absorption of x-rays are everyday examples of single-quantum phenomena, but your concept of particles jumping around is far too naive to encompass them - though it's sometimes used to explain nuclear magnetic resonance to beginners.

Some of my colleagues use protons and neutrons to treat tumors. Should we tell the patients that they are purely hypothetical particles?
« Last Edit: 06/10/2015 17:08:30 by alancalverd »
 

Offline mathew_orman

  • Sr. Member
  • ****
  • Posts: 132
    • View Profile
Re: The Discovery of the Neutron or is it?
« Reply #22 on: 07/10/2015 08:42:19 »
and cannot get any closer to the nucleus
What force will prevent that?
Also, there is only one logic of continuity of motion regardless of size scale...
No force required to prevent it. The nucleus and electrons in an atom all have the same center of mass—it is impossible for them to be any closer.
Is that a new law of superposition of matter?
If so then unlimited number of assumed subatomic elements can have one common center of mass?...
Also, you need to provide real example not a philosophical one...
 

Offline mathew_orman

  • Sr. Member
  • ****
  • Posts: 132
    • View Profile
Re: The Discovery of the Neutron or is it?
« Reply #23 on: 07/10/2015 08:51:05 »

Well, please give an example  where a particle would vanish from current position and appear  in different location or change velocity and or position (jump) instantaneously...


The emission and absorption of x-rays are everyday examples of single-quantum phenomena
Some of my colleagues use protons and neutrons to treat tumors.
Adding a word 'quantum ' is not increasing the volume of knowledge about a phenomena...
Your colleagues ware thought to use names but in reality the cancer cells are disabled by ionizing radiation...
 

Offline alancalverd

  • Global Moderator
  • Neilep Level Member
  • *****
  • Posts: 4704
  • Thanked: 153 times
  • life is too short to drink instant coffee
    • View Profile
Re: The Discovery of the Neutron or is it?
« Reply #24 on: 07/10/2015 10:44:31 »
True, but some of that radiation is deflected by an electric field, and some isn't. Some is deflected by a magnetic field, and some isn't. Some of it travels at the speed of light and some doesn't. Some is strongly absorbed by lead and some by water (it's a quantum thing, but I'm sure there's a logical explanation too). So we poor deluded morons think there are several different types of ionising radiation, and use them to do different jobs.

Fortunately both the patients and the cancer cells believe in this ridiculous juju. But you know better. 
« Last Edit: 07/10/2015 10:47:22 by alancalverd »
 

The Naked Scientists Forum

Re: The Discovery of the Neutron or is it?
« Reply #24 on: 07/10/2015 10:44:31 »

 

SMF 2.0.10 | SMF © 2015, Simple Machines
SMFAds for Free Forums
 
Login
Login with username, password and session length