What is Experiment: Definition and 1000 Discussions

An experiment is a procedure carried out to support or refute a hypothesis. Experiments provide insight into cause-and-effect by demonstrating what outcome occurs when a particular factor is manipulated. Experiments vary greatly in goal and scale, but always rely on repeatable procedure and logical analysis of the results. There also exists natural experimental studies.
A child may carry out basic experiments to understand how things fall to the ground, while teams of scientists may take years of systematic investigation to advance their understanding of a phenomenon. Experiments and other types of hands-on activities are very important to student learning in the science classroom. Experiments can raise test scores and help a student become more engaged and interested in the material they are learning, especially when used over time. Experiments can vary from personal and informal natural comparisons (e.g. tasting a range of chocolates to find a favorite), to highly controlled (e.g. tests requiring complex apparatus overseen by many scientists that hope to discover information about subatomic particles). Uses of experiments vary considerably between the natural and human sciences.
Experiments typically include controls, which are designed to minimize the effects of variables other than the single independent variable. This increases the reliability of the results, often through a comparison between control measurements and the other measurements. Scientific controls are a part of the scientific method. Ideally, all variables in an experiment are controlled (accounted for by the control measurements) and none are uncontrolled. In such an experiment, if all controls work as expected, it is possible to conclude that the experiment works as intended, and that results are due to the effect of the tested variables.

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  1. B

    Stern-Gerlach experiment Problem

    Homework Statement Homework EquationsThe Attempt at a Solution (a) : There is no interference. (b) : Interference And i don't know how to approach (c), (d)
  2. M

    What are the errors in Young's Double Slit experiment?

    Homework Statement I am having troubles trying to figure out systematic and random errors when conducting Young's double slit experiment. Homework Equations NA The Attempt at a Solution I have found one error which could be correct, it is the fact that the laser was not at right angles with...
  3. brainpushups

    A simple collision experiment and a question

    I recently came across https://www.physics.uoguelph.ca/~jlhunt/morph/5exp.pdf paper in The Physics Teacher that describes a handful of experiments which can be performed with common materials. The collision experiment in particular caught my eye because it seems like most collision experiments...
  4. dylanreynolds1

    I Thought Experiment Contradiction: Find the Answer

    Hello all, I have a question that's been bothering me the last few days and wasn't sure where to turn. Recall the original Special Relativity thought experiment: A spaceship travels at constant velocity v, moving in the positive x direction. An observer on the spaceship emits a photon directly...
  5. B

    I I say that this experiment confirms Schrodinger's Cat....

    I'm having a fun little argument with my wife, about an article posted on www.sciencedaily.com. I say that the article CONFIRMS that Schrodinger was RIGHT. My WIFE says that this confirms that Schrodinger is WRONG. The article concerns the quantum techniques used creating the shortest pulse of...
  6. A

    Why are there modes in cantilever beam oscillation equations

    I'm doing an experiment measuring the relationship between length of a cantilever beam and period of oscillation when I twang it on one end, but I can't seem to understand the equation. The equation for measuring frequency is given here:https://www.hindawi.com/journals/amse/2013/329530/ but I...
  7. M

    Calculating Magnetic Field from FFT Amplitude

    So a little bit of background: I work in an undergraduate lab at UMass Amherst and am currently building/optimizing a faraday magnetometer for use in the Muon g-2 experiment at Fermilab. The magnetometer works as follows. A laser is shone through a crystal with a particular Verdet Constant at...
  8. N

    Double slit experiment with a glass-covered slit of unknown n

    Homework Statement A double-slit experiment uses a helium-neon laser with a wavelength of 633 nm and a slit separation of 12mm. When a thin sheet of glass is placed in front of one of the slits, the interference pattern shifts by 5 fringes. When the experiment is repeated under water, the shift...
  9. donavi

    I The spin of the photon -- a weird experiment with a laser

    Hello everybody, I'm playing with a ne -ne laser And i conducted an interesting experiment I did colliding beams the type of interferometer Fabry Pero between the mirrors I put the cuvette with different substances I tried to detect changes of polarization of the laser beam with the help of a...
  10. Paulo Figueiredo

    B Michelson-Morley Exp: Surprise of Result

    Hello! Why the surprise in the result of the Michelson-Morley experiment? If the mirrors were in earth, i think that the system is a galileu system. If the Earth is moving or if the Earth was not moving the result, in my opinion, were the same.
  11. T

    I Galileo's experiment and a lack of understanding....

    Could anyone offer me a little help with understanding why the principles demonstrated in Galileo's (probably fictional, I know) experiment involving two spheres of the same mass from a tower don't apply in the following situation please? As I understand it, the principle is essentially that...
  12. Maaruk

    I Time Dilation: Hafele-Keating Experiments

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  13. NihalRi

    Effect of mass on skid distance of car experiment

    Homework Statement I know this is long, but that is only because this question requires me to be thorough, conceptually I think it isn't difficult. To make it easier to read I bolded the important parts. In Physics lab, we were told to conduct an experiment to investigate the effect off mass...
  14. Jens Lundell

    B Electron in the double-slit experiment

    Newbie here: Is the (single) electron leaving the "machine" in the famous double-slit experiment the same one hitting the screen? Please give a short explanation on how this is proved, thank you.
  15. S

    I Exploring the Experiments & Interpretations of Quantum Physics

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  16. M

    Unraveling the Mystery of "Floating Rule" in an Experiment

    Today I was leading my students in an experiment that would reveal "the rule for what floats." We had previously floated (or sank) various objects in regular, room temperature tap water. I then weighed out 100 grams each of sugar and water, mixed them together and weighed them again. To my...
  17. M

    I Double slit experiment in 3 dimensions?

    Has anyone performed the double slit experiment in three dimensions? By this I mean, having double slits and a detection screen on three sides? This would imply there are 6 slits and 3 detection screens. What would we observe? Would we see the electron exhibiting wave like behavior (ie...
  18. Auto-Didact

    A Experiments probing the macroscopic limits of QM

    This thread is to serve as both a compilation and ground of discussion of key experiments, both historical and planned, which attempt to probe possible macroscopic limits of QM, taking into account e.g. some particular gravitational/optical/mechanical/superconducting/etc aspect and/or...
  19. M

    B Double slit experiment wave collapse

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  20. N

    Double Slit experiment separation

    Homework Statement A double-spit experiment is performed with light of wavelength 600 nm. A wide viewing screen is 2m behind the grating. What is the distance between the two m=2 bright fringes on the screen? The slit separation given is 0.1 mm. Homework Equations Given the wavelength and...
  21. Viopia

    B Double slit experiment -- consciousness and information

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  22. S

    I Explain the orbital physics of the JAXA Tether experiment?

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  23. Y

    I Double slit experiment questions

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  24. Buzz Bloom

    I What's currently going on with the KATRIN experiment

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  25. SuchBants

    Problem graphing Irradiance and distance experiment

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  26. C

    Wind Turbine Blade Experiment: What is the Optimal Number for Maximum Voltage?

    Not really a homework question but this is probably the best place to post it. I'm interested in what people think about the following experiment and the wording of one of the follow up questions that came with it. It was set as part of UK GCSE Physics coursework for the 14-15 age group. 1...
  27. H

    An experiment using a diffraction grating with

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  28. wolram

    B Double slit experiment for layman

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  29. Robertphysics

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  30. N

    Interesting experiment about the attraction between two magnets

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  31. A

    B When was the first double slit experiment done using a detector?

    When was it first experimentally seen that particle detectors can change the interference pattern effect expected in a double slit experiment? Is it still theoretical? What were some double slit experiments in the early era of quantum mechanics? How were they handled?
  32. pittsburghjoe

    I Criss-cross multiple double slit experiment paths?

    Has someone attempted to criss-cross multiple double slit experiment paths? The purpose would be to mix paths of observed and free particles. I want to know if clumps and fringes appear everywhere or we would get something new.
  33. K

    A Thought experiment: How to find Chronons?

    Hi! We were recently discussing if time appears quantified. I found the theory about "chronons" (quantums of time) on Wikipedia and I know, those are very theoretical constructs and as far as I found out there is no current research if chronons even exist. But I was wondering if somebody has an...
  34. Dopplershift

    I Understanding the Einstein Train Thought Experiment: Scenario Comparisons

    Hey all, I was re-reading my quantum mechanics books and I noticed that different books have different scenarios for the Einstein Train thought experiment. And I was just wondering if I understood it correctly. Scenario 1: A person inside a moving train flashes a light beam that goes in both...
  35. V

    Chemistry Equilibrium Experiment

    Homework Statement For this experiment we studied the equilibrium system CuCl42+(aq) ↔ Cu2+ + 4Cl-(aq) + heat Net reaction shift is observed by looking at colour changes -CuCl42+(aq) become green (shift to left) - Cu2+ is blue and Cl-(aq) is colourless (shift to right) What occurs when you put...
  36. C

    B Delayed choice experiment and FTL communication

    I've been thinking about a communication system that could allow faster than light communication. The basic principle that would make this system work come from the double-slit experiment and Wheleer's delayed choice experiment, taking advantage of the different patterns that would appear on a...
  37. Davephaelon

    I Double slit experiment with electrons

    When it's desired to detect an electron coming through one of the slits in the mask of the double slit experiment, how exactly is the detection done without blocking the electron from reaching the background screen? In another thread it's mentioned that a semiconductor detector is placed behind...
  38. E

    I A question about the delayed choice quantum eraser experiment

    This delayed choice quantum eraser experiment captured my attention and after deep thought about it, I find it really startling and totally punishing to my common sense. My question is: Can you predict the future, say, a human's mind, using the quantum eraser? I imagine a modified version of the...
  39. T

    Experiment using a Wheatstone Bridge

    Homework Statement Determine the unknown resistance using a Wheatstone Bridge. Homework Equations Unknown Resistance = known resistance (100-Length) / Length The Attempt at a Solution I've connected the set up as shown in the pictures but my only concern is, I don't have a resistance box so...
  40. G

    B Electron diffraction experiment puzzle

    In classical Physics wave theory (GCSE level) we talk about waves diffracting through a gap if the gap is similar size to (or smaller than) the wavelength of the waves. When firing fast electrons at a carbon target (teltron tube A level type apparatus) is it sufficient to say that if the de...
  41. Quotidian

    B A non-physicist's question on the double-slit experiment

    OK this question comes from a late-night discussion, er, argument, about the famous double-slit experiment. One of the interesting facts about the double-slit experiment is that the interference pattern that appears on the screen doesn't seem to be affected by the rate at which electrons are...
  42. O

    Role of accelerating voltage in Davisson Germer experiment

    Hello everyone, We know Davisson & Germer experiment confirms the wave nature of electron(matter). Positions of Constructive Interference produces high intensity. So at different scattering angle intensity should be different. That's fine I understand why scattering angle(position) matters for...
  43. T

    Experiment: Measuring the focal length of a converging lens

    Homework Statement You are required to set up a light source, an object grid, a converging lens and a screen so that a quantitative investigation of object and image distances can be performed. Tabulate corresponding object and image distances (p and p' respectively). Also tabulate values of...
  44. C

    B Why target is putting rotated on DDX experiment?

    Hello. I have a question about DDX (double-differential cross-sections) experiment. On DDX experiment, people are putting the target rotated about 45 degree. I wonder why they put the target rotated and what benefit exist because of that. Thank you
  45. D

    Thompson's cathode experiment

    Homework Statement What is the distance Δy between the two points that you observe? Assume that the plates have length d, and use e and m for the charge and the mass of the electrons, respectively. Express your answer in terms of e, m, d, v0, L, and E0. Homework Equations kinematics...
  46. Cocoleia

    Young's double slit experiment with the source being a slit

    Homework Statement Here i am asked to find the phase difference. Homework EquationsThe Attempt at a Solution I know that usually the equation is mλ=asinΘ
  47. S

    B Gravitational lensing thought experiment

    Hello all, I'm starting to learn the math in physics and have the following thought experiment I want to use to work through something I own. The setup: There is a wall 10m from the center of a 1m diameter sphere. There is a 1m diameter light source casting a 1m diameter shadow on the wall...
  48. Bloopy

    B Doubt regarding Rutherford's Alpha Scattering Experiment and Impact Parameter

    It is mentioned in my Textbook that if alpha-particle has large impact parameter, it gets scattered through small angles and vice versa. I understand that impact parameter is defined as the perpendicular distance between the path of a projectile and the center of the nucleus. I am unsure how...
  49. Alanay

    Could Walking Like a Gorilla Increase Strength?

    I was just thinking while watching the Zookeeper movie. If a child is born and we teach it how to move on it's legs and knuckles instead of just it's legs would it end up being a great deal stronger than people it's age? I think the most weight ever lifted by man was 450 KG, and an average...
  50. bubblegumandcameras

    Motion under variable acceleration experiment

    Used a mass attached to a dynamic cart via pulley to examine motion under variable acceleration. As the mass was increased, my calculated friction force shows a decrease. I know that friction should increase with larger mass. Any suggestions as to why my calculations show a decrease? Used the...
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