Wikipedia:Peer review/Electron/archive1

Electron

• A script has been used to generate a semi-automated review of the article for issues relating to grammar and house style; it can be found on the automated peer review page for October 2008.

This peer review discussion has been closed.
Greetings! I've been expanding and referencing this vital-rated article, with the goal of eventually taking it to FA. My philosophy was to present a fair level of detail about the electron at the particle-interaction level, then use mostly summary-style for higher-level interactions such as atomic orbitals and conductivity. The only section I haven't fully tackled yet is "Applications"; I'll work on that in the days ahead. I'm also thinking about adding a "Hazards" section to cover the effects of beta radiation.

I hope the content is at least moderately accessible to any educated person (i.e. a non-specialist like me); please point out where the descriptions seem confusing. Some quality copy editing would also be much appreciated!

Thanks, RJH (talk) 16:28, 14 October 2008 (UTC)

• Comment. I'll take a look when I can, but one quick thought... Having a "hazards" section in electron to discuss beta radiation is equivalent to having one in water to discuss drowning -- in my view, it's true but not notable. -- SCZenz (talk) 16:44, 15 October 2008 (UTC)
  • True. Perhaps it is best left for the beta radiation article. Thank you.—RJH (talk) 17:46, 15 October 2008 (UTC)

Ruhrfisch comments: This seems pretty good over all, here are some suggestions for improvement.

• A few places need references, for example In radiation therapy, electron beams are used for treatment of superficial tumours. (might this be a place to discuss the hazards of beta radiation)? My rule of thumb is that every quote, every statistic, every extraordinary claim and every paragraph needs a ref.
• I also note that the preceding sentence is a one-sentence section - I think the section should either be expanded or combined with another.
  • Done and done.—RJH (talk)
• The tone of this does not seem very encyclopedic "It takes about 150 attoseconds for an electron to circle the nucleus of an atom. An attosecond is related to a second as a second is related to the age of the universe," explained Johan Mauritsson, an assistant professor in atomic physics at the Faculty of Engineering, Lund University.[117][118]
  • That's one of those entries that was left over from before the page was reworked. I was reluctant to remove it, but I can see your point. It has been extracted.—RJH (talk)
• It seems as if the article becomes more random in spots as the article progresses - the preceding quote seems to come a bit out of left field
  • Are there any other points of randomness that concern you? Unfortunately there is a fair amount of material to summarize, so it had to jump around a little. But I'll see what I can do.—RJH (talk)
• Keep units so they are easier for casual readers to compare, so In blue light, conventional optical microscopes have a diffraction-limited resolution of about 100 nm. By comparison, electron microscopes are limited by the de Broglie wavelength of the electron, which is equal to 3.69 × 10-12 m.[129] For example, the TEAM electron microscope is capable of 0.05 nm resolution:... goes from nm to m then back to nm.
  • Okay. RJH (talk)
• Per WP:MOS#Images, images should be set to thumb width to allow reader preferences to take over. For portrait format images, "upright" can be used to make the image narrower.
  • True. However, I think some images need to be larger in order to make the details visible. An example is the cosmic ray tree.—RJH (talk)
• I thought See also was for links not in the article already.
  • Opinions seem to vary on this, but I'll try some pruning and see who complains.—RJH (talk)
• Would it help to split the notes and make them separate from the refs.
  • Done.—RJH (talk)

Hope this helps. If my comments are useful, please consider peer reviewing an article, especially one at Wikipedia:Peer review/backlog (which is how I found this article). Yours, Ruhrfisch _><>°^° 03:33, 24 October 2008 (UTC)

Thank you for doing a thorough review of the article and providing helpful feedback.—RJH (talk) 17:11, 24 October 2008 (UTC)

• I will review the article next week. Ruslik (talk) 20:23, 25 October 2008 (UTC)
  • I look forward to your expert comments. Thank you.—RJH (talk) 16:41, 27 October 2008 (UTC)

Review by Ruslik:

• 1. Modern particle physics subsection:

  a) "In 1937, a similar effect was demonstrated with a beam of electrons;" Actually they received Nobel prize in 1937. The discoveries were made 10 years earlier, in 1927 (in case of Davisson).

  Fixed.

  b) I would remove paragraph about Feynman path integral, which is too complicated for this article.

  Done.

  c) Instead I would add a paragraph about Paul Dirac equation and prediction of antiparticles (positron), and a paragraph about development of quantum electrodynamics at the end of 1940s (works of Julian Schwinger on anomalous magnetic moment of electron).

  d) 209 Gev is the energy in center of mass of electron-positron pair. The actual energy of particles was only half of that. In addition cited ref [48] does not say anything about energy.

  Fixed.

• 2. Classification subsection:

  a) I think lepton charge should not be mentioned. Now the article does not explain what it is and why it is important.

  Sorry but I don't understand why I wouldn't mention the electrical charge here (for disambiguation purposes).

  Sorry, I meant lepton number, which is sometimes called a charge. Ruslik (talk) 20:23, 28 October 2008 (UTC)

  Fixed.

  b) The third paragraph needs to mention that positron had been predicted by Dirac.

  I expanded the history.

• 3. Fundamental properties subsection:

  a) "When an electron is stationary with respect to an observer, its rest mass is" Contradictory sentence. Will the rest mass change if the electron is not stationary? In addition rest mass is not widely used term in modern physics. Say simply mass.

  Fixed.

  b) "However, the rest energy of the electron has been shown to vary by 10−6–10−9 eV because of local fluctuations of temperature and magnetic field" I would drop this sentence. Those "renormalizations" of the electron mass have nothing to do with real rest mass. Physicists sometimes introduce various mass-like parameters for the convenience. It is better to call them quasi-masses.

  Removed.

  c) "This is the radius that is inferred from the electron's electric charge, by using the classical theory of electrodynamics alone and ignoring quantum mechanics." I would put a footnote here with a formula.

  d) I think positrons and the fact that their properties are same (except the sign of charges) as those of electrons should be mentioned in this subsection.

  Done.

• 4. Virtual particles:

  a) The term Dirac constant is almost never used now. Say simply reduced Plank constant.

  Okay.

  b) The third paragraph should make it clear that the mass of the electron is not in reality reduced as result of radiative corrections—it is simply taken from the experiment, and all terms that influence the mass are replaced with this real mass during renormalization.

  I attempted to address this, but I'm not completely sure I understood his concern correctly.—RJH (talk)

  c) Please, add a note to explain how ${\sqrt {3}}/2$ is obtained.

  Done, I hope.

  d) The paragraph begining with "The concept of a dimensionless particle possessing..." should be removed. I actually do not understand what it is about. The concepts used in it are too complicated for readers including even some physicists. :-)

  I'd actually like to include a simple explanation here for the spin of a dimensionless particle, because it seems particularly relevant, at least to me. I tried to simplify it even more, and I added another reference.—RJH

  e) In the last paragraph. I think it is not necessary to introduce g-factor. Say simply that the magnetic moment of electron is almost equal to one Borh magneton. 0.1% difference is explained by radiative corrections (see Schwinger above).

  Fixed.

This is the first part of my review. I will continue later. Ruslik (talk) 10:14, 28 October 2008 (UTC)

This is excellent feedback. Thank you.—RJH (talk) 19:04, 28 October 2008 (UTC)

The second part of the review:

• 5. Interaction subsection:

  a) "Electrons are a key element in electromagnetism, a theory that is accurate for macroscopic systems, and for classical modeling of microscopic systems'" quite a meaningless sentence, in my opinion. Electromagnetism is not a theory, it is a set of phenomena. It should be omitted or rewritten. For instance "Electrons are a key element in the electron theory of metals, atomic and molecular physics and in chemistry."

  I modified the text.

  b) "quanta of electromagnetic energy" -> "quanta of electromagnetic field". Photon is a quanta of everything: momentum, angular momentum, energy.

  c) Fine structure constant is also called a dimensionless charge squared $\alpha =e^{2}/(\hbar c)$ (in CGS system). If $\hbar =c=1$ assumed, $\alpha =e^{2}$.

  I think this may be a little off topic for this article. So I'm planning to leave it for the fine structure constant article.—RJH (talk) 20:12, 13 November 2008 (UTC)

  d) "The full electromagnetic effect from a moving charge can be derived mathematically using the Liénard-Wiechert potential, which includes special corrections for when the velocity is close to the speed of light; known as relativistic velocities." an awkward sentence. I suggest: "The electromagnetic field of an arbitrary moving charged particle is expressed by the Liénard-Wiechert Potentials, which are valid even when the particle's speed is close to that of light."

  Done.

  e) The attempt to differentiate between cyclotron radiation and synchrotron radiation is a hair splitting. Such radiation is usually called synchrotron now regardless of the energy of the electrons.

  Okay.

  f) "In the theory of electroweak interaction, the electron forms a weak isospin doublet with the electron neutrino." Actually only left-handed fermions forms isospin doublets; right-handed are isospin singlets.

  Fixed.

  g) As I said above I would move information about positrons (last paragraph) into Fundamental properties subsection.

  Okay.

• 6. Atom subsection:

  a) "An electron can be bound to an atom by the attractive coulomb force generated by the nucleus." I suggest "An electron can be bound to an nucleus by the attractive coulomb force."

  Done.

  b) "Electrons can transfer between different orbitals by the emission or absorption of photons with an energy that matches the difference in potential." This sentence creates an impression that electrons can only move between orbitals by emitting photons. However there are other processes like: particles (electron) impacts, Auger effect etc.

  Added.

  c) "Thus the magnetic moments of an atom's electrons cancel each other out, with the exception of the outermost electron." another exception is electrons in d/f orbitals.

  I modified the description.

• 7. Motion and energy subsection:

  a) "faint bluish light called Cherenkov radiation" The light can be of any color, not necessary bluish.

  Done.

  b) "For the 51 GeV electron above, proper-velocity is approximately γc,[note 7] making the wavelength of those electrons small enough to explore structures well below the size of an atomic nucleus." This is not proper velocity, this is phase velocity of the de Broglie waves.

This was the second part of the review, I will finish it tomorrow. Ruslik (talk) 11:02, 29 October 2008 (UTC)

The final part of the review:

• 8. Formation section:

  a) The article should mention that formation of the neutral atoms in the universe is called recombination. It actually happened 300,000 years after Big Band, not one million.

  Okay.

  b) "The concentrations of mass in the universe allow stars to form"—strange sentence. I suggest "Sometime after recombination the first starts formed."

  Done.

• 9. Observation section:

  a) "Measurements allowed the dimensionless g-factor of the electron to be measured ..." Say simply "Measurements allowed the magnetic moment the electron to be measured ...".

• 10. Other subsection should generally discuss synchrotron radiation sources, not only FELs.

I completed the review, and hope that it will be helpful. Ruslik (talk) 12:55, 30 October 2008 (UTC)

Thank you. It'll take me a little while to get these implemented.—RJH (talk) 18:53, 30 October 2008 (UTC)

Some comments

• the picture while is nice, I think a more representative one could be found. maybe a lighting?
  • I was just thinking about that. The Crookes tube image is both representative and demonstrates the particle property of electrons. The Shuttle image can be relocated to the applications section. I just need to find a replacement image for the history section.—RJH (talk)
• in the etymology section it would be nice to give who/when named electricity after the greek elektron
  • I'll see what I can dig up.
• discovery might sound better than identification
  • Okay, reluctantly.
• you could try to split the last part of the infobox into "Physical properties"; also "Composition: elementary particle" is a bit awkward
  • That would effect multiple articles, so I feel that can't make it just to address this topic. However, I left a message in the Physics project to see if there is interest in this suggestion.
• "This polarization was confirmed experimentally in 1997 using the Japanese TRISTAN particle accelerator" does this mean that the actual charge of an electron is more than e?
  • Yes, in the sense that the charge measurement varies with distance.
• "interaction with other particles" sounds better than "interaction"
  • It is also about interaction with electrons.
• "Atoms"=>"Atomic orbitals"
  • I'll have to disagree. Orbitals is only part of the section.
• "Conductivity"=>"Electric conductivity"
  • Conductivity also includes heat.
• "Formation"=>"Synthesis"?
  • I had considered that name, but it didn't seem to quite fit all the content in that section. "synthesis ... a process which combines together two or more pre-existing elements resulting in the formation of something new."

Nergaal (talk) 21:44, 12 November 2008 (UTC)

Thank you for your feedback.—RJH (talk) 20:45, 13 November 2008 (UTC)