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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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Was there experimental data underlying Einstein's $E=mc^2$?

It is customary to provide formulas to describe experimental data, namely in regression. So, when Einstein proposed the formula $E = mc^2$ (I reckon the original formulation was not like this, but I ...
Gigiux's user avatar
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1 answer
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How did Rutherford estimate the number of Au atoms in the foil in his experiment?

In the Rutherford experiment (where he found the diameter of the nucleus of an Au atom by estimating the probability of an $\alpha$-particle to bounce back on a gold foil), how did Rutherford estimate ...
niobium's user avatar
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non-integer candela measurements and candela manipulation

What was the oldest way to quantify or measure candelas or control it as as an independent variable (luminous intensity)?
Coo's user avatar
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3 votes
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What is the oldest way to measure the voltage?

What is the oldest way to measure the voltage? I mean the experimental way or apparatus.
Coo's user avatar
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About the acceptance of Newton's light experiment

I originally posted this question in History Stack Exchange, but I was recommended to post it here instead. My question starts with the following statement from a book I'm reading "Moreover, ...
madame p's user avatar
2 votes
0 answers
83 views

What was defined first and how? The ampere or the vacuum permeability?

I've been looking up the history and evolution of the seven base units and am currently checking out the ampere. What I've found is that 1A is defined as the current in a wire which would experience a ...
SpectraXCD's user avatar
2 votes
1 answer
112 views

In Geiger-Marsden experiments how was charge of alpha particle and charge of gold atom found?

Here: https://en.wikipedia.org/wiki/Geiger%E2%80%93Marsden_experiments Some calculations were done to show how JJ Thomson's model predicts alpha particles will be mostly undeflected by the gold foil. ...
Saif's user avatar
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1 answer
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Do gravitational waves hold the record of longest delay between prediction and confirmation under the same theory?

This question is similar to What was the longest delay between prediction and confirmation of a theory? but I want to frame it in a different way. I am looking for long delays between prediction and ...
Mauricio's user avatar
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3 votes
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How was crystallography studied before X-ray diffraction?

Nowadays, the crystal structure of some solids can be determined by using X-ray diffraction techniques based on Bragg's law and so on. However, after reading the timeline of crystallography, it seems ...
Verktaj's user avatar
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Resource recommendation for experiments that led to major concepts in physics

Any resource recommendations for history of physics giving special attention to experiments that led to certain concepts and theorems in physics? For example what led to the motivation of definition ...
GedankenExperimentalist's user avatar
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53 views

Is there a resource which explains the history of how the Leidenfrost effect was explained?

The context is that I am trying to teach some middle school students that in science, a question could be posed/ an observation made but being able to answer or explain it, might take a couple of ...
Vishnu Agnihotri's user avatar
7 votes
2 answers
256 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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When Was The Leidenfrost Effect First Demonstrated By Touching Molten Metal?

The Leidenfrost Effect is a described as follows on Wikipedia: The Leidenfrost effect is a physical phenomenon in which a liquid, close to a surface that is significantly hotter than the liquid's ...
azoundria's user avatar
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1 answer
99 views

History of determining the specific charge of the electron by balacing electric and magnetic forces

Nowadays is a well known high school or undergrad lab experiment to determine the specific electron charge by using a Wien-filter setup as described for example here. Up to now I thought that this ...
Julia's user avatar
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2 votes
1 answer
132 views

Is there a "Moore's Law" of length-determining apparatuses?

Is there a "Moore's Law" of length-determining apparatuses? Viz., has the precision of state-of-the-art length measurement apparatuses doubled periodically throughout history?
Geremia's user avatar
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7 votes
1 answer
503 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
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1 answer
58 views

Deflection of the pendulum arm in Cavendish experiment

I'm trying to find how Cavendish calculated the deflection of the arm due to the gravitational attractions of the weights. He gives for the deflection B=6.18 divisions. "Motion of the arm on ...
zeynel's user avatar
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Computing Gravitational constant G from Cavendish's data

I'm trying to compute the value of G from Cavendish's own observations. I get $G_{Cav}=5.27501×10^{−10}$ which is 8 times bigger than the accepted value of $G_{True}=6.67430×10^{−11}$. Do you see ...
zeynel's user avatar
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The housing of the Cavendish Experiment

[I posted this to History, but it was suggested that History of Science and Mathematics would be a better choice. So I'm posting it here too.] I’m working to build the Cavendish experiment of 1798 ...
zeynel's user avatar
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4 votes
1 answer
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Units in J.J. Thompson's m/e experiment

The original paper by J.J. Thompson, where he exposes his experiment to measure $m/e$ can be found here. (Note that Thompson actually measured $m/e$ whereas the modern discussion is in terms of $e/m$.)...
ZeroTheHero's user avatar
3 votes
0 answers
169 views

How did Rutherford detect the deflected alpha particles?

All I know is that detecting the deflecting alpha particles was a very tedious process, so much so that that was probably one reason why he asked Hans Geiger and Ernest Marsden to do the experiment. ...
Adil Mohammed's user avatar
5 votes
1 answer
191 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
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
6 votes
1 answer
765 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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2 votes
1 answer
663 views

Do Nobel prizes tend to go to theorists or experimenters?

Obviously not all cases are such that a theory is presented without experiment, and then the necessary experiment is done separately by another person... But when this IS the situation, to whom does ...
nchoir's user avatar
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3 votes
0 answers
157 views

Diffraction pattern of Michelson's echelon

Has anyone used Michelson's echelon (pictured below), a very famous type of diffraction grating in the 1920s? I am wondering how did the diffraction image look like from this type of transmission ...
ACR's user avatar
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49 views

Which scientist(s) first measured the elementary charge and how did they do it? [duplicate]

I would be grateful if anyone could shed some light on these questions. Which scientist(s) first measured the elementary charge? If it wasn't measured in a straightforward experimental setting, and ...
alghazali's user avatar
6 votes
0 answers
136 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
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
1 vote
0 answers
61 views

Signal Processing research: Was matter ever learnt? [closed]

I understand that every energy in our universe can act as a wave or as a mass. If I understand correctly, the scientific and engineeric field of signal processing generally deals with signals from ...
variableism's user avatar
0 votes
1 answer
289 views

Was Einstein's "Maschinchen" a predecessor of the photomultiplier tube?

Einstein once got involved in true experimental physics. That is, he designed his little machine (Maschinchen, in German, a word that makes me laugh; Einstein's Maschinchen...) to detect small ...
Deschele Schilder's user avatar
2 votes
1 answer
127 views

Earliest numeric value for helium D3 line

In late 1868, Norman Lockyer discovered the existence of the D3 emission line of helium in the solar spectrum. What was the earliest published example of a numeric value for the wavelength of this ...
WhatRoughBeast's user avatar
2 votes
1 answer
161 views

Did tobacco smoke confound the results of an experiment by entering a reaction with the subject of study?

I dimly remember watching a popular sciencie movie that mentioned an experiment conducted by a pair of great physisicists (Einstein was one of them, unless my memory is playing tricks on me) that had ...
gaazkam's user avatar
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2 votes
0 answers
40 views

Who invented the quadrupole lens for charged particles?

I am wondering who actually invented the (magnetic) quadrupole lens or who used it for the first time. I have found some papers from the 50s and 60s about more complicated systems based on Quadrupoles,...
Felix Kern's user avatar
3 votes
0 answers
79 views

Experimenters regretting throwing away data?

Modern experiments, especially in fields like particle physics, often collect far more data than they can process and save. Similarly, I can imagine that historical experimenters were limited by how ...
Heisenbugs's user avatar
1 vote
0 answers
169 views

How did Faraday determine the Faraday's constant?

Here is the reference. I'm wondering how he experimentally proceeded to derive the fact the if we pass 96485 Coulombs through a solution, then 1 gram equivalent of substance is electrolyzed.
ric.san's user avatar
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4 votes
3 answers
201 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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3 votes
1 answer
211 views

Are there any photographs of the original apparatus used by Hertz to demonstrate the photoelectric effect?

There are many schematics and many photographs of tubes used later but I cannot find a single photograph of the original apparatus. Even the sketches that were made in the late 19th century are ...
DrFalcon's user avatar
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4 votes
2 answers
189 views

What was known about the properties of the nucleus before the Liquid drop model was proposed?

What was known about the properties of the nucleus (its shape, its density etc) and the nuclear forces before the Liquid drop model was proposed? I believe that some empirical knowledge must be out ...
Solidification's user avatar
2 votes
0 answers
62 views

How did Millikan consider utilizing oil to help determine the charge of the electron?

Robert Millikan's oil drop experiment help to find the charge of electrons using oil. An x-ray was aimed at the oil drops to give them a charge, and the droplets were attracted to the negative plate. ...
Nachiket Kulkarni's user avatar
-1 votes
3 answers
1k views

Was there ever a mathematician or physicist who spearheaded a concerted effort to create a flawless musical instrument?

Specifically, is there any research paper or record of where someone renowned in their field performed experiments by using the properties of physics, engineering or mathematics to develop a musical ...
Nachiket Kulkarni's user avatar
1 vote
1 answer
110 views

What was the content of Sakharov's research into cosmic rays?

According to Wikipedia, Sakharov in his early scientific career investigated cosmic rays. It offers no other details. It claims that it was for this work that he was awarded his doctorate. However ...
Mozibur Ullah's user avatar
6 votes
2 answers
1k 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
1 answer
676 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
1 vote
1 answer
171 views

How was it determined that the photoelectric effect is independent of the intensity of light?

How as light intensity measured or determined around 1900? For example, when it was determined that the photoelectric effect was independent of the intensity of the light beam, but rather that it ...
Frédéric's user avatar
3 votes
1 answer
488 views

Does anyone know of any examples of the Magnus effect in a real battle?

I've read a lot about the Magnus effect altering the trajectories of cannonballs and musketballs. Robins noticed it with Musket balls and Magnus with canonballs, but presumably they weren't the first ...
Tom Lancaster's user avatar
3 votes
1 answer
183 views

What was this experiment tainted by the observer effect?

I once heard a cautionary tale about the dangers of the observer-expectancy effect. It was at least presented as a true example from the history of science, but I'm having trouble identifying the ...
aschepler's user avatar
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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
-1 votes
2 answers
358 views

Electric spark discovery

I am searching it on Google but I am not finding,who had discovered static electric spark for the first time,that later Benjamin Franklin proved that this spark(already discovered spark) is same as ...
user230507's user avatar
9 votes
3 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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