Understanding, Considering, Confirming Neutron.

[URAIN]

I am not expert in physics. When I was reading a physics book, author explained that why the discovery of neutron delayed and how it was confirmed.

 

Author’s writing is followed.

 

Assume a invisible ball is on the billiards table. One visible ball moving on green surface of the table and suddenly, without any reason the ball goes in another direction. Scientists do not accept the, moving of anything or changing direction of anything without any reason. Therefore they decided that visible ball dashed with invisible ball. That invisible ball is the neutron.

 

Is giving this example for discovery of neutron correct ? Is there any other examples, for perfect understanding the neutron ?

[Rade]

Here it is, the paper in Nature on discovery of neutron by Chadwick:

 

http://web.mit.edu/22.54/resources/Chadwick.pdf

 

You will see the the neutron was not discovered experimentally by Chadwick in the way described in the book on physics you have.

[URAIN]

Here it is, the paper in Nature on discovery of neutron by Chadwick:

 

http://web.mit.edu/22.54/resources/Chadwick.pdf

 

You will see the the neutron was not discovered experimentally by Chadwick in the way described in the book on physics you have.

 

 

I have the book of famous scientist Alexander. I. Kitaigorodsky. Before giving above example he says, before 1920 Rutherford assumed that a particle has existed in the atom which is electrically neutral and having equal mass of proton. He assumed this because like charges always repels but in experiment positive charged alpha particle go inside the atom. (This is translation)

 

Discovery of neutron delayed because electrically charged particles were found by ionization path. But electrically neutral particle has not any actions with the electron therefore that will not leave any path. Hence neutron may found from base of secondary effects.

 

Then after he gave above example of invisible ball on the billiards table.

 

He also said when beryllium bombarded with alpha particles then neutron was found.

 

Chadwick own comment from ‘nature’

 

“If it be supposed that the radiation consists of quanta, then the capture of the α-particle by the Be9

nucleus will form a C13 nucleus

 

It is not easy to reach the final decision between the two hypotheses. Up to the present, all the evidence is in favour of the neutron, while the quantum hypothesis can only be upheld if the conservation of energy and momentum be relinquished at some point.

J. Chadwick.

Cavendish Laboratory,

Cambridge, Feb. 17.

 

It indicates that conservation of energy and momentum has main role to recognize the neutron. Hence neutron is like invisible ball on the billiards table.

[URAIN]

why the neutron stars are named as neutron stars (If you will give link, then with that link please give some explanation in some sentences).

 

I am asking this because, I think there may be charges are neutral but it is not contain same symptom of invisible neutron.

[maddog]

why the neutron stars are named as neutron stars (If you will give link, then with that link please give some explanation in some sentences).

I am asking this because, I think there may be charges are neutral but it is not contain same symptom of invisible neutron.

Neutron Stars are named as such because they are in a form of condensed matter. The force of gravity has pushed everything together forming a massive amount of neutrons. It is not that neutrons are invisible. Being neutral they are independent of any interaction with this EM force. That is their path is not diverted under an electric or magnetic field.

 

maddog

[Qfwfq]

Being neutral they are independent of any interaction with this EM force. That is their path is not diverted under an electric or magnetic field.

Not quite. They have magnetic dipole moment, therefore a gradient in magnetic field causes a force on them.

[Rade]

Of interest is that the magnetic dipole moment of the neutron is a negative number, about -1.913 (u/nm)

 

Also, the neutron has a root mean square charge radii that is negative, about -0.116 fm^2

 

So, neutron is really not all that "neutral", lots of negativity brewing inside.

 

See here for physical information from experiments for the neutron:

 

http://pdg.lbl.gov/2004/listings/s017.pdf

[maddog]

Not quite. They have magnetic dipole moment, therefore a gradient in magnetic field causes a force on them.

I stand corrected, in that over ambitiously "globbed" the Electric (mostly what we studied in Modern Physics) with the Magnetic field (never actually did any experiments with neutrons to consider this phenomena).

 

maddog