Talk:Experiment

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Total restructuring[edit]

This article is a complete and horrible mess. I'm attempting to reorganize and rewrite. I propose the following basic structure: intro, definition(s) of an experiment (with different meanings from different disciplines), history (with reference to new History of experiments page), some kind of discussion of styles/approaches/purposes for experiments, a section contrasting experimental and observational approaches, and then a section on ethics. Then, more connections should be drawn to Design of experiments and Randomized experiment. My thought is to leave statistics out of this page and put those on Randomized experiment. This should be a nontechnical introduction to the background of experiments, and those other pages can get into more detail, but the pages need to work together. Thosjleep (talk) 21:39, 4 September 2012 (UTC)


Interent Resources[edit]

I found these to be interesting resources, Tube 8

Natural experiment example[edit]

"For example, after Albert Einstein advanced his theory of general relativity according to which massive objects such as the sun should cause curving of spacetime, an observation was made of the light from a star which passed near the sun. This was done during a solar eclipse in order that light from the star could be detected. It was found that the light from the star was indeed deflected by the sun."

This was used as an example of a natural experiment. However, the discription is very minimal, and this experiment probably deserves its own page, which I couldn't find. Once that page is written up, we can reincorporate this experiment into the article.adam

If I recall correctly, this experiment (performed I think during a solar eclipse in the 1920s) was actually pretty bad - there was a lot of experimental error, and although it is commonly referenced in popular discussions, it wasn't a particulalry convincing result. The michelson morley experiment is a better example, IMHO. Chas zzz brown 23:43 Jan 12, 2003 (UTC)

Harris77 writes: I personally do not like the term natural experiment. I think the article should talk about naturalistic observation.

Also, i think that the heading should be "Studies" then talk about the different type of studies (correlational, clinical, case study and experimental). It would be a lot of work to change this and I don’t think I should

I am considering creating an article "Scientific Studies" and listing the studies.

Maybe "natural experiment" is not the right term, but the idea of testing a hypothesis with a prediction is part of the scientific method. We argue that, if Einstein's theory is correct, then we will see a certain amount of "bending" of light rays during an eclipse. Accordingly, Einstein and his supporters would agree that if the observations aren't within certain limits, then the theory is contradicted.
(Disclaimer: My great grandfather Charles Lane Poor, an astronomy professor, initially denounced Einstein's theory when observations of one eclipse failed to show sufficient light bending. I think I can still write neutrally about this, but if you think there's a WP:COI which I cannot overcome, let me know and I'll bow out.) --Uncle Ed (talk) 14:54, 13 April 2010 (UTC)

hard science and soft science[edit]

Note on hard/soft science: Please do not delete this reference, as I believe it is an important aspect of the nature of science, though I may not have used the best words to identify this issue. I do not mean to imply that there is any such thing as an absolute ?hard science? or ?soft science?, or that a scientist working in a ?softer? field is any less of a scientist than one working in a ?harder? field. In fact, the soft sciences may require more competent and imaginative scientists because they are working with more constraints than those who work in the hard sciences. All that I wish to point out is that all sciences have their limits, and the study of each phenomena will be limited in different ways. To a large extent, fields may be arranged along a spectrum from soft (most limited) to hard (least limited), but in comparing some fields it is not possible to say that one has more limits than the other, only that they have different limits.

While this idea of hard/soft science is pretty common, I am unaware of any formal treatment of the issue. Perhaps it is covered in the philosophy of science section. Anyway, I believe that we should incorporate this into Wikipedia somewhere, and there should be a link to such a page from this page. If you can think of a better way of expressing this idea than ?hard/soft science?, please replace the term with the appropriate term. adam


This is a good start! Some other thoughts; maybe they should go in the experimental method article, or maybe here...

  • what makes a "good" experiment? one generally has a hypothesis to test; if the experiment is not well designed, it may neither support nor refute the hypothesis.
  • experimental error - what is it, and how does one attempt to reduce it?
  • replicability - easier to define for physics, harder to define for sociology.
  • the role of statistical analysis and meta-analysis in drawing conclusions from experiments.
  • a list of cool experiments that we can refer to (hopefully covered in Wikipedia...)

Other thoughts as they occur to me... Chas zzz brown 23:43 Jan 12, 2003 (UTC)

I had thought of a list of experiments. There are many experiments described in wikipedia...just do a search for "experiment". I read many of them when I wikified the term "experiment" to link to this page. Anyway, we should probably categorize them. One option is to categorize them by field (Physics, Economics, Astronomy, etc.) or we could categorize them as Controlled experiments, natural experiments, quasi-experiments, or thought experiments. adam

In my view, the present article doesn't start out well.
As for: Experiment: An experiment is [...] to identify a causal relationship between phenomena.

What's "causal" about the experimental determination of particle masses, for instance?
But that's not an experiment, it's a measurement! (sarcasm) Perhaps this just shows the bias that I have aquired from my studies of molecular biology, where we don't have any universal constants to measure. I made an effort to account for psycology and the social sciences, but it didn't occur to me that I would need to make an effort to think of things from a physicist's perspective. That's a strange type of experiment (to me). I vaguely remember the original experiment. Do measurement experiments even have a control? Should they be included as a different type of experiment? It sounds like a purely descriptive process. Are all measurements experiments? What about measurements of CO2 concentration or the measurement of the height of trees in a forest.
My dictionary (Webster's new world) defines experiment as "a test or trial untertaken to discover or demonstrate something." adam

I object to the word "verify" in the definition. I propose that the word "support" be substituted. Experiments can ONLY falsify hypotheses, at least in scientific method. Also, nowhere are mentioned other roles of experimentation. What about the role of experiment in discovery ? user:DCDuring




We might distinguish experimental determinations from statistical analysis and meta-analysis of experimental determinations ...
Is this the same as "measurement" and "analysis of measured data"? (I'm not sure what "meta-analysis" is) If so, I think it omits the idea of a controlled experiment. Controlled experiments require the comparison of two measurements, and to maximize confidence, these measurements should be made simultaneously...they shouldn't be separated and treated as independent measurements. Just make sure that isn't left out of the final article. adam

As for: An experiment is a set of actions and observations performed [...]

I prefer an experimental determination, or measurement, (in any one trial) to be characterized as:
The systematic acquisition of observational data, and application of a reproducible analysis procedure to the data, in order to derive one definite result value (within a range of confidence)
This sounds good. My only concern is that it seems to emphasize quantification, which isn't always essential (especially in biology).adam


Regards, Frank W ~@) R 02:52 Jan 13, 2003 (UTC).



As for: it seems to emphasize quantification, which isn't always essential (especially in biology) [...] Controlled experiments require the comparison of two measurements

Therefore it does seem essential, including in biology, that any one of these (two or more) rather simple and quantitative measurements can be obtained separately (albeit perhaps in simultaneous trials), and that their result values are commensurate between trials.
This is the sort of situation that I'm thinking of: We do an experiment with two samples. At the end of the experiment, we report that "sample A has a signal that is 60x as strong as sample B". We repeat the experiment the next day, and we find that the signal from sample A (day 2) is 1/5 the signal from sample A (day 1), however when comparing the samples from day 2, sample A is still 60x as strong as sample B. This could happen for several reasons; perhaps one of our reagents degraded (a radioactive tracer?), or the cells were growing at 37.2 degrees instead of 37 degrees. I suppose it would be possible to perform the experiment such that we get some sort of absolute value, but it would be extremely tedious and that value would apply just to one very narrow set of conditions. We avoid this issue by focusing on the comparison between the control and the experimental sample, and we avoid all those little complications by functionally treating them in the same way. By "functionally", I mean that we grow cells in the same incubator at the same time, trusting that there is a minimal difference in conditions within the incubator, rather than trying perfectly control the conditions in an absolute, measured sense. Perhaps this all beside the point, and the experiments as I describe them are just a way of working around the fact that we cannot make perfect measurements and have perfect control over the conditions of the experiment.
Regarding quantification: A biologist might report "the treatment caused an increase of signal from the nucleus. Therefore, our modifications caused the signal producing molecule to be targeted to the nucleus." We can draw firm conclusions and increase our knowledge of how the cell works without making any reference to numbers. Of course, numbers are nice when we can get them, but we

can't always get them with a reasonable amount of work.


Finally, the word "value": My first response to this word is "numbers!", which is what set me off. However, I suppose that "True" is also a value, and "nucleus" could also be a value. But what we need to think of is how the reader will interpret this, not what the complete, "real" meaning of the word is. adam

As for: My dictionary (Webster's new world) defines experiment as "a test or trial untertaken to discover or demonstrate something."

Along with this, I'd prefer to emphasize that "something" needs to be definite, and to be derived from observations.


As for: Are all measurements experiments? What about measurements of CO2 concentration or the measurement of the height of trees in a forest.

Well, on one hand, it seems straightforward to patch up a measurement to obtain a statement of a test or demonstration, e.g.
It has been tested whether, and demonstrated that, the CO2 concentration in these trials was less than 10 %.
On the other hand, I agree, considering correlations between commensurate measurements is different (and indeed more advanced) than the notion of one measurement itself.

As for: Just make sure that isn't left out of the final article.

I certainly prefer that, too; if the present article on Experiment emphasized the role of measurements in order to obtain Controlled experiments; and vice versa, that (sets of) individual quantitative Measurements provide the basis for more sophisticated and derivative experimental procedures.
Besides, being a relative newbee Wikipedian, I'm still trying to determine whether and how expressions of such preferences are supposed to be honored in the resulting articles ...
Try to do the best that you can.  :^) In general, try not to cut things out of the article (without moving them somewhere or such). If you make a change and I think it is stupid and much worse than the original, I can always revert to the original...but that is essentially declaring war, so it is to be avoided. Anyway, you have a good point, so I wouldn't do that. I guess if you made a change and I thought that it left out an important point, then the ball would be in my court and I would have to try to rewrite it to incorporate the things that both of us think are important. As it is right now, I'd rather not make the modifications myself because I'm not sure I understand exactly what you are proposing, so I'd rather that you make the modifications that you see fit and then I'll judge that against my understanding of the issue. Good luck! adam

As for: I'm not sure what "meta-analysis" is

As far as I understand the Wikipedian who introduced this notion in this page, it seems to be concerned with how to obtain advanced experimental procedures (such as controlled experiments) from commensurate result values, obtained by sets of individual measurements.
Okay, that's pretty much what I had guessed. I'd rather not use that term in the article unless it has a good description. adam
Best regards, Frank W ~@) R 20:05 Jan 13, 2003 (UTC).

Dependent and independent variables[edit]

I'm concerned that this article doesn't mention dependent and independent variables by name (they may be implied in some places). It seems to me this is integral to the definition of an "experiment". I will return when I have time and attempt to provide this terminology in the article. I also think, as much as possible, the article should reflect what is generally true of experimentation without making too much of "hard science" and "soft science" differences. These may be interesting philosophical issues for somewhere else, but they are not central to the concept of experimentation. Any experiment - be it in physics, psychology, or trying to figure out why your entertainment center in your living room isn't working, shares essential features. These, I think, should be the focus of a general article on Experiment. Feedback before I take a stab? SJS1971 00:17, 20 January 2007 (UTC)

Quotes[edit]

The following were removed from the article to this talk page, pending proper citation to the source. The last one may be a hoax. --Bejnar 18:58, 28 May 2007 (UTC)

"We have to learn again that science without contact with experiments is an enterprise which is likely to go completely astray into imaginary conjecture." — Hannes Alfven
"Today's scientists have substituted mathematics for experiments, and they wander off through equation after equation, and eventually build a structure which has no relation to reality." — Nikola Tesla
"To experiment is the most unique of human attributes" Rossafar Gerium

Quotes belong on Wikiquote anyway, not in the article (unless there's some context they belong in). Also, both "Rossafar Gerium" and his quote get zero ghits; I'm not going to say that the quote is a hoax, but it appears entirely unattributable. Zetawoof(ζ) 19:30, 28 May 2007 (UTC)

Following these comments (and the absence anybody favoring the quotes), I'm going to remove the quotes again. Perhaps removing the quotes again will prompt somebody to explain why the quotes belong here (rather than Wikiquote), when they appear in no reputable source (on experiments) familiar to me. Kiefer.Wolfowitz (talk) 16:48, 11 February 2010 (UTC)

Natural experiment[edit]

A natural experiment is typically the observation of a system that receives a shock of some kind---where there is a clear change in the exposure (or hypothetical "treatment"). An example is Snow's observational study of cholera. There was no randomization. However, there was a change in the pump, which reduced the cholera dramatically.

Are there any objections to rewriting this section, following e.g. Chapter one of Freedman's Statistical Models? Kiefer.Wolfowitz (talk) 18:12, 12 February 2010 (UTC)

Needed Improvements[edit]

Wow, this article is in poor shape for a topic that is so central to science. It is poorly organized, poorly referenced, contains lots of jargon, is overly centered on the statistical meaning of hypothesis testing (rather than its more historical scientific meaning), and generally inaccessible to school age science students who probably make up the bulk of its readership. I suggest the following improvements: 1) Give the article historical context and accessibility with a small number of examples of how experiment played an important role in some of themost notable discoveries in the history of science. 2) Show the common elements of the experimental process as well as the differences in physics, chemistry, and biology. 3) Make ample use of citations so that the article meets Wikipedia standards for verifiability. 4) Use more notable examples of observational studies, natural experiments, etc. The article should probably not contain many examples that are not covered in a good high-school science program, but should skillfully use the examples to elucidate and highlight the essential elements of experiment as part of the scientific method. Elements of experimental design as based on college-level statistics are more of an advanced topic that should not dominate this article, but can be mentioned in appropriate sections and given a link to the article on design of experiments.Michael Courtney (talk) 14:24, 18 February 2010 (UTC)

Re Notable examples: David A. Freedman's Statistical Models explains natural experiments with Dr. Snow's research on cholera in London c. 1858, controlled randomized experiments with the HIPP trial, and observational studies with broccoli and cancer. Kiefer.Wolfowitz (talk) 15:10, 18 February 2010 (UTC)
I also feel that Replication of results needs to be enlarged into a section, or maybe even into a separate article of its own. Doing someone else's experiment over again is important, not only in science but in engineering:
  • Regarding the Lexus GX 460, which Consumer Reports warned people not to buy, AP wrote, "In a statement Toyota said it is concerned with Consumer Reports' findings, adding that its engineers will try to duplicate the magazine's tests to determine its next steps." [1]
The principle of letting one's work be checked by others, combined with a healthy dose of "skepticism" from one's fellow scientists and engineers, would seem to be essential to advancing scientific knowledge and engineering art. (I hope this is not my own opinion and that I'm not indulging in WP:OR. Rather, I seek help from other contributors here to determine if these ideas are supported by the literature.) --Uncle Ed (talk) 14:46, 13 April 2010 (UTC)

Misuse of sources[edit]

A request for comments has been filed concerning the conduct of Jagged 85 (talk · contribs). Jagged 85 is one of the main contributors to Wikipedia (over 67,000 edits, he's ranked 198 in the number of edits), and practically all of his edits have to do with Islamic science, technology and philosophy. This editor has persistently misused sources here over several years. This editor's contributions are always well provided with citations, but examination of these sources often reveals either a blatant misrepresentation of those sources or a selective interpretation, going beyond any reasonable interpretation of the authors' intent. I searched the page history, and found 20 edits by Jagged 85 in March 2010. Tobby72 (talk) 20:56, 8 June 2010 (UTC)

Having read the transcript of the charges and the editor's agreement to reform, I looked at a few of these sources and have the same concerns that much seems based on unreliable sources. Please provide reliable sources and double check the citations before returning an edited version to the article. Thanks, Kiefer.Wolfowitz (talk) 19:16, 10 June 2010 (UTC)

Alhazen[edit]

Ibn al-Haytham used experimental method to establish that light travels in straight lines in his Book of Optics (1021).

A version of the experimental method was developed by the Iraqi physicist and scientist, Ibn al-Haytham (Alhazen),[1] who is considered the 'father of modern optics'.[2] He used experimentation and mathematics to obtain results in his Book of Optics (1021).[1] In particular, he combined observations, experiments and rational arguments to support his intromission theory of vision, in which rays of light are emitted from objects rather than from the eyes. He also demonstrated that the ancient emission theory of vision supported by Ptolemy and Euclid (in which the eyes emit the rays of light used for seeing), and the ancient intromission theory supported by Aristotle (where objects emit physical particles to the eyes), were both wrong.[3] Ibn al-Haytham's experimental method consisted of the following procedures:[4]

  1. Explicit statement of a problem, tied to observation and to proof by experiment
  2. Testing and/or criticism of a hypothesis using experimentation
  3. Interpretation of data and formulation of a conclusion using mathematics
  4. The publication of the findings

One aspect associated with Ibn al-Haytham's optical research is related to systemic and methodological reliance on experimentation (i'tibar) and controlled testing in his scientific inquiries. Moreover, his experimental directives rested on combining Classical physics ('ilm tabi'i) with mathematics (ta'alim; geometry in particular) in terms of devising the rudiments of what resembles a hypothetico-deductive procedure in scientific research. This mathematical-physical approach to experimental science supported most of the propositions in his Book of Optics and grounded his theories of vision, light and colour, as well as his research in catoptrics and dioptrics. His legacy was elaborated through the 'reforming' of his Optics by Kamal al-Din al-Farisi (d. ca. 1320) in the latter's Kitab Tanqih al-Manazir (The Revision of [Ibn al-Haytham's] Optics).[5][6][7]

The conjecture that "light travels through transparent bodies in straight lines only", was corroborated by Alhazen only after years of effort. His demonstration of the conjecture was to place a straight stick or a taut thread next to the light beam, to prove that light travels in a straight line.[8] Ibn al-Haytham also employed scientific skepticism and emphasized the role of empiricism. He also explained the role of induction in syllogism, and criticized Aristotle for his lack of contribution to the method of induction, which Ibn al-Haytham regarded as superior to syllogism, and he considered induction to be the basic requirement for true scientific research.[9]

Medieval observatories[edit]

I removed this section because it lacks any discussion of testing hypotheses on fresh observations, and the relation of the observations to scientific theories.

The first astronomical observatories in the Muslim world emerged by the early 9th century.[10][11] The most famous Islamic observatories were the Al-Shammisiyyah observatory founded in 825,[12] the Maragheh observatory founded in 1259, and the Ulugh Beg Observatory founded in 1420. During the Mongol Empire, Islamic astronomers built such an observatory in China,[13] after which Chinese astronomers founded the Gaocheng Astronomical Observatory in 1276 and the Beijing Ancient Observatory in 1442.

I would suggest deleting most of the history, which are often extended discussions of the scientists's special sciences and not their contributions to experimentation and experimental theory. I would suggest retaining part of the material on Bacon and Galileo, and removing the paragraphs on Pasteur, etc. which belong in other articles, imho. Kiefer.Wolfowitz (talk) 19:56, 10 June 2010 (UTC)

Replicable tests is a key scientific issue[edit]

THis article is far too much ablut the experiments them selves than the methology. The main thing is that if somthing can be shown wrong by an experiment it is a single event if it can't be replicable by any others having the right equipment for the test, getting the same results. The key factor of science is the same method and the same gear leads to the same results independent of who is doing the test. That is why tests of experiments are published. It is not by being publiched but being replicated by (any) others it gets its scientifical value. There is a huge mistake by many to believe the publication of the test is the proof, it is making the tabloid the truth as well. It is rather the fact that if any are doing the same test with the same method and gear, getting the same result, that is science. The article is just a way of communications and the greatness of the authour is if it leads to a common acceptance of the same method leads to the same result. — Preceding unsigned comment added by 77.219.206.215 (talk) 00:22, 3 May 2012 (UTC)

  • In many cases, the only major impact to scientific study is by "published" results, so that is the reason for the emphasis, although I agree the text could note that the replication alone of the experiment, to confirm results, is the key activity, and the publication is just a formality. -Wikid77 (talk) 08:36, 11 June 2013 (UTC)

Focusing on methodology versus examples[edit]

I am wondering if the article could be reworded, as a means of clarifying the concepts, by a better separation of the description of methodology, from the variation examples which show the application. -Wikid77 (talk) 08:28, 11 June 2013 (UTC)

Simplifying examples[edit]

Perhaps some examples are too complicated and have overshadowed the basic ideas of how experiments can be conducted. -Wikid77 (talk) 08:35, 11 June 2013 (UTC)

This article seems clearly to meet at least the C-class quality standards now. I'm reassessing it as C-class, if no one objects. -Bryanrutherford0 (talk) 16:48, 21 July 2013 (UTC)

  1. ^ a b Rosanna Gorini (2003), "Al-Haytham the Man of Experience, First Steps in the Science of Vision", International Society for the History of Islamic Medicine, Institute of Neurosciences, Laboratory of Psychobiology and Psychopharmacology, Rome, Italy:

    "According to the majority of the historians Ibn al-Haytham was the pioneer of the modern scientific method. With his book he changed the meaning of the term optics and established experiments as the norm of proof in the field. His investigations are based not on abstract theories, but on experimental evidences and his experiments were systematic and repeatable."

  2. ^ Verma, R. L. (August 1969), Al-Hazen: father of modern optics, Al-Arabi 8: 12–3, PMID 11634474 
  3. ^ D. C. Lindberg, Theories of Vision from al-Kindi to Kepler, (Chicago, Univ. of Chicago Pr., 1976), pp. 60-7.
  4. ^ Bradley Steffens (2006). Ibn al-Haytham: First Scientist, Morgan Reynolds Publishing, ISBN 1599350246. (cf. Bradley Steffens, "Who Was the First Scientist?", Ezine Articles.)
  5. ^ Nader El-Bizri, "A Philosophical Perspective on Alhazen’s Optics," Arabic Sciences and Philosophy, Vol. 15, Issue 2 (2005), pp. 189-218 (Cambridge University Press)
  6. ^ Nader El-Bizri, "Ibn al-Haytham," in Medieval Science, Technology, and Medicine: An Encyclopedia, eds. Thomas F. Glick, Steven J. Livesey, and Faith Wallis (New York — London: Routledge, 2005), pp. 237-240.
  7. ^ Bradley Steffens (2006), Ibn al-Haytham: First Scientist, Chapter Five, Morgan Reynolds Publishing, ISBN 1599350246
  8. ^ p. 136, as quoted by Shmuel Sambursky (1974) Physical thought from the Presocratics to the Quantum Physicists ISBN 0-87663-712-8.
  9. ^ Plott, C. (2000), Global History of Philosophy: The Period of Scholasticism, Motilal Banarsidass, p. 462, ISBN 8120805518 
  10. ^ Kennedy, Edward S. (1962), Review: The Observatory in Islam and Its Place in the General History of the Observatory by Aydin Sayili, Isis 53 (2): 237–239, doi:10.1086/349558 
  11. ^ Micheau, Francoise, "The Scientific Institutions in the Medieval Near East", pp. 992–3  Missing or empty |title= (help), in (Rashed & Morelon 1996, pp. 985-1007)
  12. ^ Langermann, Y. Tzvi (1985), The Book of Bodies and Distances of Habash al-Hasib, Centaurus 28: 108–128 [112] 
  13. ^ Richard Bulliet, Pamela Crossley, Daniel Headrick, Steven Hirsch, Lyman Johnson, and David Northrup. The Earth and Its Peoples. 3. Boston: Houghton Mifflin Company, 2005. ISBN 0-618-42770-8