Talk:Oil drop experiment

Millikan's sidekick a Bollywood Star?
According to the intro Akshay Kumar worked with Millikan on his famous experiment. I can find no record of that anywhere but this page. If there was a Kumar, I don't think it was the Bollywood actor, Akshay Kumar, linked to on the oil drop experiment page. Slhumph (talk) 14:07, 26 May 2011 (UTC)

Out of place sentence
This sentence: "Millikan also enjoyed a nice glass of scotch in the evening after a long day of experiments." at the end of the fifth paragraph under "Background" seems out of place. I'm not sure its even factually accurate (seems like the kind of thing someone would throw in as a joke) If it is accurate, then it should be moved to a less suspicious looking location. - Feb 18 2009
 * Removed for obvious reasons. I'm pretty surprised nobody noticed this before, but the whole page is a prose nightmare. Eebster the Great (talk) 00:35, 20 February 2009 (UTC)

internal links
There are far too many of them in this article. —Preceding unsigned comment added by Icarus66 (talk • contribs) 16:07, 22 September 2007 (UTC)

Misleading summary
I believe the summary might be misleading as is most popular literature on the subject In contrast in the method section it's shown that Millikan did not balance the electric and gravitational forces on each drop, doing this would be really difficult, instead he observed the oil drops while under the effect of a known electric field and gravity, and also under gravity alone. I know that the other section is not reference enough, I'm currently working on some advances on this experiment (making it more accurate, easy and cheap), and on the papers Millikan published, the method reflected it's one I advocate. JunCTionS 18:10, 25 July 2006 (UTC)

Difficult doesn't begin to explain it. :) Millikan must have had the patience of a saint, I swear. -- Popefelix 00:17, 26 Apr 2005 (UTC)

I'm also striking out the broken links in the article, and adding one or two of my own. -- Popefelix 00:26, 26 Apr 2005 (UTC)

I updated one of the broken links, and e-mailed Dr. Covault to see if he has a current URL for his oil drop lab. In the meantime, the Covault link has been deleted. -- Popefelix 00:47, 26 Apr 2005 (UTC)

type of oil?

 * The oil used is the type that is usually used in vacuum apparatus. This is because this type of oil has an extremely low vapour pressure.

Would it be possible to be more specific? There's nothing helpful at vacuum. Chick Bowen 04:51, 10 October 2005 (UTC)


 * Nowadays in student labs liquid latex is used, HTH. --Bmalicoat 05:30, 1 March 2006 (UTC)

Charge screening?
Wouldn't the QED concept of charge screening invalidate oil-drop experiments? That implies that the real charge of an electron is actually significantly larger than what such an experiment could measure, and that one was only measuring the effective charge at some particular distance. -76.209.50.77 17:42, 27 October 2006 (UTC)
 * I am not sure if I understand what you are asking, but the electric field between parallel plates is essentially uniform, so the height of the drop between the plates is irrelevant.
 * It's clear the person asking this question has no idea what he is talking about.

Experiment controversy
It is now known that Millikan devised and conducted this experiment in collaboration with his grad student Harvey Fletcher. I've added this to Fletcher's page, but it ought to go here as well. Posting this in case I don't get around to it and someone else wants to. Electrolite 22:04, 4 February 2007 (UTC)

Also, a citation is needed for the experiment referred to. Milikan's publications on variations of this experiment are from 1910 & 1911. If he did perform it in 1909 I cannot find any references. Q-Bit. (talk) 16:06, 22 April 2021 (UTC)

See Also section
I've removed the See Also section per WP:LAYOUT, which says that such sections "should ideally not repeat links already present in the article". Robert Millikan is prominent featured and wiki-linked in the text already. Electrolite 03:34, 12 February 2007 (UTC)


 * OK. I agree with you. Thanks. nicky_008 15:40, 12 February 2007 (UTC)

Check it out!...New pictures on article
I have added some pictures that usefull for article such as the orginal Millikan’s oil-drop apparatus picture, Millikan's setup for the oil drop experiment, etc. Let's check it out or add some more. nicky_008 18:06, 20 February 2007 (UTC)

check the method section, the last equation
In my mind, it should be qE=\W(1+\frac{v_2}{v_1}\)\?

Rather expensive and difficult to do properly?
Request change in last sentence of "Background", my professor told me that he did that already in high school. Maarten,dutch (talk) 18:30, 7 February 2008 (UTC)

Misleading intro
The last phrase of the intro seems to be misleading it gives the modern value of the charge of the electron, not the value the experiment revealed. They interpreted this as the charge on a single electron: 1.602 × 10−19 coulomb. Compare to the phrase lower down: In his Nobel lecture, Millikan gave his measurement as 4.774(5) x 10−10 statcoulombs,[7] which equals 1.5924(17) x 10−19 coulombs. Plse. s.o. check and correct. 76.97.245.5 (talk) 09:19, 6 February 2009 (UTC)

How many drops?
How many drops were measured in the original experiment? 142.162.20.206 (talk) 16:34, 4 April 2009 (UTC)

Millikan's experiment and cargo cult science
An editor suggested that the 'Millikan's experiment and cargo cult science' section (reporting of Feynman's comment) constitutes 'undue weight'. I disagree. I think that this section is entirely appropriate because Milikan's experiment gives an archetypal and sobering example of scientific herd mentality. I'm grateful for the details in this section, as I googled Millikan's experiment hoping to find just such details. —Preceding unsigned comment added by 61.68.58.209 (talk) 20:52, 20 October 2010 (UTC)

I think this section is interesting and makes sense to include in the article, but its title 'Millikan's experiment and cargo cult science' is highly misleading and inappropriate. The quote is taken from the chapter titled 'Cargo Cult Science' in Feynman's book, but it has no connection to cargo cult science (except via the broader discussion of science and intellectual honesty which is the theme Feynman is exploring). So, I changed the section title to 'Millikan's experiment as an example of psychological effects in scientific methodology' (admittedly a bit awkward, but the main point is to have a title that is informative and explains the relevance of the content of the section to the article - if anyone thinks of a better name that doesn't contain the words 'cargo cult science', feel free to change it). Primalbeing (talk) 21:53, 18 December 2011 (UTC)

Lack of citation
The following sentence appearing in the "Background" section lacks a reference. "Thomas Edison, who had previously thought of charge as a continuous variable, became convinced after working with Millikan and Fletcher's apparatus"

I do not know how to put the questionable whatever on it, so if someone else can help with that cite this sentence, that would be great. LimpSpider (talk) 11:52, 14 December 2012 (UTC)
 * I added a ref. --Kkmurray (talk) 14:47, 14 December 2012 (UTC)

First sentence needs clarification.
Looking at the first sentence: "The oil drop experiment was an experiment performed by Robert A. Millikan and Harvey Fletcher in 1909 to measure the elementary electric charge (the charge of the electron)." So the oil Drop experiment was used to elementary electric charge, BUT only of an electron? Ok. Now if you click on the "elementary electric charge" hyperlink the first sentence will inform you:

"The elementary charge, usually denoted as e or sometimes q, is the electric charge carried by a single proton, or equivalently, the negation (opposite) of the electric charge carried by a single electron."

So is the Oil Drop Experiment page suggesting the results are only valid for electrons charges but not protons charges, which according to elementary electric charge page linked in the first sentence is telling me they are the same but one is negative and the other positive? Or are electrons just sensitive and need special affirmation through name recognition? — Preceding unsigned comment added by 76.105.148.203 (talk)
 * I'm not sure how practical it is to perform the experiment by using oil with a positive charge. If you did I would imagine that the molecules composing the oil would be selectively ionized leaving you with positively charged droplets with integer charges of e but none with charge e. In the very least it would complicate things since the electrons are bound to the nuclei and you might end up removing several valence electrons instead of just one as you might want. Regarding the wording I think its fine.Chhe (talk) 00:45, 13 April 2015 (UTC)
 * And if you are asking why the charge on a proton wasn't measured, it is because protons are very tightly bound inside the tiny nucleus of an atom, by the strong force. A lab experiment around 1910 would have had no way to generate free protons. You might ask why the positive charge on positrons wasn't measured, and the reason there is that positrons are difficult to work with at low energies because they are antimatter. Electrons are easy to manipulate at low energies. See also the Franck and Hertz experiment, the Photoelectric Effect (subject of Einstein's first major paper), and Compton Scattering for more or less similar experiments. David Spector (talk) 15:04, 27 July 2021 (UTC)

Charge on a droplet
" ionized by an x-ray, making them negatively charged." How does an X-ray produce a negative ion? Does it not remove electrons from the oil leaving it with a positive charge? 193.117.241.181 (talk) 13:37, 31 January 2023 (UTC)