Re: Who discovered the proton?

Hi.  
Here are 3 sources of info.  Take what you will.



While studying streams of ionized gas Wien, in 1898, identified a positive 
particle equal in mass to the hydrogen atom. Wien, with this work, laid the 
foundation of mass spectroscopy. J J Thomson refined Wien's apparatus and 
conducted further experiments in 1913 then, after work by E Rutherford in 
1919, Wien's particle was accepted and named the proton. 
Wien received the 1911 Nobel Prize for his work on heat radiation. 

Source: http://physics.rug.ac.be/Fysica/Geschiedenis/Mathematicians/Wien.html
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While studying streams of gas atoms and molecules from which electrons had 
been stripped (ionized), Wilhelm Wien (1898) and J.J. Thomson (1910) 
identified a positive particle equal in mass to the hydrogen atom. Ernest 
Rutherford showed (1919) that nitrogen under alpha particle bombardment 
ejects what appear to be hydrogen nuclei. By 1920 he accepted the hydrogen 
nucleus as an elementary particle, naming it proton.

Source: http://www.britannica.com/bcom/eb/article/7/0,5716,63187+1,00.html

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   Question
Who discovered the proton? And how was it discoverd? 
Asked by: Undisclosed Sender 


   Answer
In most popular texts on particle physics you see a long laundry list of 
particles and their discoverers : 

1897 Thomson discovers the electron
1911 Rutherford discovers the nucleus
1932 Chadwick discovers the neutron

and so on and so on. Somewhere between Thomson and Chadwick, physicists 
realized that there are positively charged constituents of the nucleus, 
which we call "protons". The way this happened was a gradual process, and 
that is why it is hard to say exactly who discovered the proton, although 
if you had put a name against it, it would be Ruthford, sort of. 

After the discovery of the electron, it was realized that there must be 
positive charge centers within the atom to balance the negative electrons 
and create electrically neutral atoms. Rutherford's discovery of the 
nucleus demonstrated that these positive charges were concentrated in a 
very small fraction of the atoms' volume. In 1919 Rutherford discovered 
that he could change one element into another by striking it with energetic 
alpha particles (which we now know are just helium nuclei). In the early 
1920's Rutherford and other physicists made a number experiments, 
transmuting one atom into another. In every case, hydrogen nuclei were 
emitted in the process. It was apparent that the hydrogen nucleus played a 
fundamental role in atomic structure, and by comparing nuclear masses to 
charges, it was realized that the positive charge of any nucleus could be 
accounted for by an integer number of hydrogen nuclei. By the late 1920's 
physicists were regularly referring to hydrogen nuclei as "protons". The 
term proton itself seems to have been coined by Rutherford, and first 
appears in print in 1920. 

An excellent reference on the history of particle physics is Abraham Pais's 
_Inward Bound_ (Oxford Press). Another good, and less bulky, overview of 
the development of particle physics is The Particle Hunters_ by Ne'eman and 
Kirsh (Cambridge Press). 

Answered by: Dr. Lee Sawyer, Assist. Professor of Physics, Louisiana Tech
Univ. 

Source: http://physlink.com/ae46.cfm



Arash E.