Questions tagged [experimental-physics]

For questions about historical physics experiments, the history of experimental methodology, observations of physical phenomena and related topics

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Timeline of measurements of the electron's charge

Where can I find a paper or reference that describes the timeline of measurements of the magnitude of the electron's electric charge. For context, Millikan's oil drop experiment in 1908 determined the ...
BMS's user avatar
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25 votes
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Is Millikan's famous oil drop experiment a fraud?

I read in my mechanics textbook written by Goodstein that Robert Millikan cherry-picked his data in his famous oil drop experiment, and now I'm left wondering about the scientific value of his results....
Shing's user avatar
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23 votes
2 answers
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When did it become possible to predict the time and place of solar eclipses?

That is, when did astronomy figure out how to predict when and where a solar eclipse will be visible? It seems people noticed fairly early on that the Sun, Moon and Earth return to the same ...
Semaphore's user avatar
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21 votes
1 answer
578 views

When & how was it known that our Sun is the same thing as the night time stars?

Who was the first person to conjecture that our Sun is just another star? Relatedly, what was the first evidence that this was true?
BMS's user avatar
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18 votes
4 answers
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Did the pioneers of nuclear physics and radioactivity eventually get sick from their experiments?

We read about nuclear physics and radioactivity in books and we know how to keep safe from their harmful effects, but the physicists who first discovered them didn't have that luxury. Did the pioneers ...
Craig Feinstein's user avatar
17 votes
1 answer
307 views

Did the Digges Telescope actually exist?

There are many claimants for the first telescope. Amongst these are the claims placed at the doors of Bacon and Digges. The Bacon claim is very sketchy, boiling down to one sentence and is easy to ...
winwaed's user avatar
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15 votes
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Discovery of Earth's magnetic field

Compasses are used for various reasons since the 2nd century BC, and for navigation in particular since the 11th century. When did people realize that the reason it indicated North have something to ...
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15 votes
1 answer
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What were the early empirical tests of Einstein's mass-energy equivalence $E=mc^2$?

Near the end of Einstein's 1905 paper on $E=mc^2$ he states (in the translation by Perrett and Jeffery): It is not impossible that with bodies whose energy-content is variable to a high degree (e.g....
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14 votes
3 answers
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How did Galileo know that objects rolling down a ramp was an accurate model for free fall?

Galileo used balls rolling down ramps to study the relationship between time and distance traveled. However, without any knowledge of physics, it doesn't seem immediately obvious that the time-...
Ovi's user avatar
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13 votes
1 answer
528 views

Why is Ingenhousz's 1784 study of fine charcoal in uncovered alcohol interpreted as Brownian motion, thus giving him priority over Brown?

I'm puzzled why the noted scientist Jan Ingenhousz's FRS reported study in the title has been almost universally interpreted by modern writers (in books, papers since ca. 1968, and now online ...
David's user avatar
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12 votes
3 answers
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How did Milikan know that oil drops would acquire only few electron charges?

In the book of Experiment in Modern Physics, by Melissinos, at page 2, it is given that: 2. The Millikan Oil Drop Experiment In 1909, R. Millikan reported a reliable method for measuring ionic ...
Our's user avatar
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11 votes
2 answers
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When and how it was discovered that sound is related to some kind of oscillations?

Sound is an oscillation of a medium (waves in the medium), and the frequency of thse oscillations we hear as the pitch. When this was discovered and by what experiment? I suppose this was already ...
Alexandre Eremenko's user avatar
11 votes
1 answer
2k views

How did Young perform his double slit experiment?

Thomas Young is famous for his double slit experiment, but I can't seem to find his experimental setup (such as how is prepared the light before it went through the apparatus. Does anyone know his ...
Quantum spaghettification's user avatar
11 votes
1 answer
540 views

Were there serious attempts to model the photoelectric effect classically?

Today we see the photoelectric effect as one of the simplest pieces of empirical evidence that leads to quantum physics. The historical development of the subject, however, seems to have involved much ...
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11 votes
1 answer
1k views

When was the division between the troposphere and stratosphere determined?

Nowadays, science is aware of the divisions of the Earth's atmosphere, particularly the division between the troposphere and the stratosphere, as shown in the diagram below: Image source When and ...
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10 votes
4 answers
365 views

What was the longest delay between prediction and confirmation of a theory?

The recent announcement of the detection of gravitational waves by LIGO comes almost exactly 100 years after Einstein predicted gravitational waves in 1916. Are there other examples (in the era of ...
Jeremy's user avatar
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10 votes
1 answer
165 views

Discovery of magnetic field reversals?

Inspired by the question Discovery of Earth's magnetic field, the article from New Zealand's webpage Discovery of the Earth’s magnetic field, also states that The earth's dynamo is unstable, as is ...
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10 votes
1 answer
477 views

Why did George Cayley never crack the stability problem?

George Cayley, aka "The Father of Aerodynamics" essentially, invented the field of heavier-than-air aerodynamics and built a number of model and man-carrying gliders, all in the first half of the 19th ...
winwaed's user avatar
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9 votes
2 answers
396 views

Could scientists of Newton's time have explored the limits of his laws of motion?

As noted on this Wikipedia page Newton's laws of motion and of gravity were "verified by experiment and observation for over 200 years" and found to be a "good approximation for macroscopic objects ...
TripeHound's user avatar
9 votes
2 answers
2k views

When was it first realized that sound travels with finite speed?

From what date can we trace the knowledge (or the hypothesis) that sound has a finite speed of transmission through air? Thunder/lightning is the most striking clue, but echoes would be the readiest ...
David Holden's user avatar
9 votes
2 answers
2k views

How did Henry Cavendish deduce the inverse square law in electrostatics from his experiment in 1772?

An elegant experiment in 1772 by Henry Cavendish. Cavendish charged a spherical conducting shell that contained within it, and temporarily connected to it, a smaller sphere. The outer shell was then ...
Hawkingo's user avatar
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1 answer
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Did Galileo bet money on the ship experiment?

Galileo's writings describe two experiments involving ships. These are summarized in the Wikipedia article Galileo's ship. (A lot of the text in the article is mine, and if there are things I'm ...
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8 votes
1 answer
1k views

speed of light measurement

while searching for different methods of speed of light measurement, i came across one of the method of fizeau discussed below which i cannot fully understand. In short,in Fizeau’s apparatus, a beam ...
user65445's user avatar
7 votes
1 answer
1k views

How did J. J. Thomson establish the particle nature of the electron?

In its article about how the electron was discovered, Wikipedia says that Thomson and his students performed experiments which suggested that cathode rays were negatively charged "particles". But even ...
user662650's user avatar
7 votes
2 answers
3k views

Did Galileo perform an experiment at the Leaning Tower of Pisa?

Galileo's pupil Viviani said that Galileo dropped unequal weights from the Leaning Tower of Pisa and observed them to take equal times to hit the ground. Galileo's own writings do not describe such an ...
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7 votes
1 answer
443 views

When was the geometric structure of a water molecule discovered?

How and when was water the structure of a water molecule (specifically the angles) discovered? Was it discovered by using a specific type of spectroscopy? I know you can derive these angles ...
Dan Barzilay's user avatar
7 votes
1 answer
1k views

Why is it said that Marie Curie died due to her work but the same isn't said for Fermi?

I learnt in school that Marie Curie died from her work at 66 years. On the other hand, Enrico Fermi, who also handled a lot of radioactive substances died of stomach cancer at the age of just 53. It ...
Rohit Pandey's user avatar
7 votes
1 answer
9k views

How were atomic weights originally measured?

According to the Science Encyclopedia, Because atoms were much too small to be seen or measured by any common methods, absolute weights of atoms could not be determined. Rather, these first ...
Doubt's user avatar
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7 votes
1 answer
140 views

When the Superconducting Super Collider was built, was the future of the site planned for?

The Superconducting Super Collider was the greatest experiment that was never built. It was cancelled in 1993 after years of planning and effort, during which there was some construction of facilities....
HDE 226868's user avatar
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7 votes
0 answers
263 views

How did early physicists experimentally assign electronic transitions in atoms?

The spectrum of hydrogen was very well studied by the mid-19th century. However, if one were doing experimental spectroscopy for more complex atoms, one would see plenty of spectral lines in the ...
AChem's user avatar
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6 votes
4 answers
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Did Hooke's law come from experiments, or was it mathematically derived from Newtonian mechanics?

Was Hooke's law first coming from experiment or from math derivation of which Newtonian mechanical laws are the only prerequisite? Also can the law itself be reinvented in this way, or is it ...
Victor's user avatar
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6 votes
2 answers
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How did people react to the realization that Aristotle's ideas had gone without question for way too long?

Recently read the book "Gravity" by George Gamow, in which he says: For centuries Aristotelian philosophy and scholasticism dominated human thought. Scientific questions were answered by dialectic ...
davelook's user avatar
6 votes
1 answer
2k views

Who really discovered/invented the Hooke's law?

According to Wikipedia, The law is named after 17th-century British physicist Robert Hooke. He first stated the law in 1676 as a Latin anagram. He published the solution of his anagram in 1678 as: ...
Diego S. Rodrigues's user avatar
6 votes
2 answers
460 views

What is the origin of "normal" in normal coordinates and normal modes?

I am trying to understand why vibrational modes of polyatomic molecules are called "normal" mode of vibrations and with corresponding normal coordinates. What is the origin of the term normal here? I ...
AChem's user avatar
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6 votes
1 answer
95 views

What was the historical importance of the discovery of high-$T_c$ superconductors?

I remember very well from my (only) class in solid state physics how enthusiastically the professor recounted the discovery of high-$T_c$ superconductors. In one particularly vivid anecdote, he ...
Danu's user avatar
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6 votes
1 answer
591 views

What did Galileo's "pulsilogon" look like?

Reading how Galileo measured time in the experiment with inclined plane, it says on Wikipedia, that: Galileo accurately measured these short periods of time by creating a pulsilogon. This was a ...
pisoir's user avatar
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6 votes
0 answers
134 views

What technology was used to determine the shape of the blackbody spectrum at the 19th century?

The shape of the blackbody radiation spectrum was known in the 19th century from experimental measurements, and before the theoretical discovery of Planck's law. At those times, how did people manage ...
Solidification's user avatar
6 votes
0 answers
165 views

Does Galileo's method of tracing a parabola actually work?

In Two New Sciences, Galileo writes: I take a perfectly round brass ball about the size of a walnut and project it along the surface of a metallic mirror held in a nearly upright position, so that ...
concertpi's user avatar
5 votes
2 answers
1k views

How did Stern or Gerlach, of Stern-Gerlach experiment, create individual silver atoms? How were they accelerated?

How, a century ago, could Stern and/or Gerlach KNOW that they had created single silver atoms? How were they moved, or accelerated?
Kurt Hikes's user avatar
5 votes
3 answers
213 views

How was the idea of observation error introduced?

The first thing a contemporary student of physics learns is the measurement error. As far as I understand, the idea of imprecision was totally foreign to natural philosophers at least until the end of ...
user58697's user avatar
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5 votes
2 answers
288 views

What did it historically mean in physics for something to "exist"?

What is the history of influential definitions of objective existence --- This Is Real, It Exists --- in physics? Where did they appear in the literature and in what context were they put forward? ...
Shing's user avatar
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5 votes
1 answer
183 views

Have there been instances in physics where different scientists have interpreted the same data differently? [closed]

Have there been instances in physics where different scientists have interpreted the same data differently? If yes, can you please give me specific examples and explain why one interpretation was ...
Vedant Rana's user avatar
5 votes
2 answers
996 views

How did Newton prove his third law of motion?

I guess it is an experimental law, so what was the experiment?
Amit Keinan's user avatar
5 votes
2 answers
295 views

High voltage / current sources in 19th century cathode ray experiments

In modern chemistry textbooks, a DC source (battery symbol) is usually shown for cathode ray tube experiments by Thomson and others. Certainly, no battery can provide very high voltages needed for gas ...
AChem's user avatar
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5 votes
1 answer
721 views

Who was first to observe or detect photons in the double slit experiment, and how did they do that?

In the early 1800s Thomas Young introduced (a thought-?) experiment also known as the two slit experiment. He discovered the strange way photons created a interference pattern on a screen. There is ...
Marijn 's user avatar
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5 votes
1 answer
653 views

Did Ptolemy and other Greek scientists actually measure the distance to the Sun?

According to Subhash C. Kak: Early Theories on the Distance to the Sun: “Pancavimsa Brahmana states that the heavens are 1000 earth diameters, de, away from the earth. The sun was also taken to be ...
Mikael Jensen's user avatar
5 votes
2 answers
212 views

Early helium spectrum measurements and their challenge for Bohr's quantum mechanics

My understanding is that explaining ortho- and para- helium spectral lines was a key motivation for Heisenberg's new quantum theory. For example, Birthwistle's 1928 "The New Quantum Mechanics&...
David Bailey's user avatar
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5 votes
0 answers
153 views

How could John Dalton hypothesised his atomic theory based on his experimental observations?

The key of this question is not simply stating the content of his theory, but telling what results or principles he had at that time and how could they lead to the theory. He was as such the first ...
user avatar
5 votes
0 answers
342 views

In which paper did the typical textbook diagrams of the Millikan experiment appear the first time?

There are two typical visualizations for one of the results of the Millikan oil-drop experiment to illustrate that only integer multiples of some elementary charge occur in nature. The first one is as ...
Julia's user avatar
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4 votes
3 answers
168 views

Significance of Higgs model used in Glashow-Salam-Weinberg theory

Sheldon Glashow, Abdus Salam, and Steven Weinberg propose the unification of the weak and electromagnetic interaction between elementary particles. Glashow, Salam, and Weinberg proposed the model ...
wonderich's user avatar
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