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. L

    I General Implications of the Double-Slit Experiment

    I've been reading about the sophisticated double-slit experiments currently being conducted by a team of physicists led by Tom Campbell. It's no secret of course that Campbell hopes that the findings of these experiments will strengthen the argument that our universe is a computer simulation...
  2. Erik Ayer

    I How Would Afshar's Experiment Affect Entanglement?

    Afshar's experiment (https://en.wikipedia.org/wiki/Afshar_experiment) sent a light beam through a double-slit to get interference, put wires in the places where there were dark fringes, then refocused the light with a lens get "image" the two slits. I'm wondering what entanglements would break...
  3. S

    I Did Schrödinger himself take his "Cat Experiment" seriously?

    In 1935, Austrian physicist Erwin Schrödinger was looking at a concept called a "superposition." Superposition is when two waves meet and overlap and interact, which can lead to different results based on the circumstances. The concept can be seen in the regular-sized world as well, in...
  4. Adrian Tudini

    Setting up an experiment for a chemical reaction

    Hi I am trying to safely setup an experiment to measure a chemical reaction with a spectral detector. I was wondering how to setup the experiment safely in front of the spectral detector? Do I have to perform some calculations based on the chemical reaction beforehand? Or what? This is an...
  5. D

    Effect Compton - Experiment (Low Cost)

    Does anyone know of any low-cost experiments that prove the compton effect?
  6. C

    F=ma experiment: Trolley being pulled by a falling weight

    The weight accelerating/pulling the trolley is changed and corresponding acceleration recorded. What I don’t understand is why the weight added/removed to the hanging weight is removed/added to the trolley
  7. K

    I Thermal interpretation and EPR experiment

    [Moderator's note: Thread spun off from previous thread due to topic change.] The thermal interpretation of the double slit experiment is very appealing alternative explanation to the Bohmian interpretation as I understood it from these discussions...
  8. C

    Young's Interference Experiment

    I wasn't sure what to do, so I started with equation (1) and used it to derive the power spectral density at point Q, $$ \begin{align} \tilde G (Q,\nu) = ~ & K_1^2 G(P_1,\nu)+K_2 ^2 G(P_2,\nu) \nonumber \\ & + 2 K_1 K_2 \left| \tilde G (P_1,P_2,\nu) \right| \cos \left[ 2 \pi \nu \frac {r_2-r_1}...
  9. R

    I Special Relativity: Comparing Lengths in Parallel Motion

    In Introduction to special relativity by Resnick,there is a thought experiment to compare lengths perpendicular to relative motion as given in the below image. What if we try to perform such an experiment to compare lengths parallel to relative motion? Suppose there are two horizontal rods...
  10. Krushnaraj Pandya

    How does the Double-Slit Experiment explain the strange behavior of electrons?

    I have always seen YouTube videos saying how an electron 'knows' when we are observing it but I always put that down to youtubers creating popular science (verging on science fiction) hype for more views. I suppose there is more science behind an electron behaving like a particle when we put a...
  11. fresh_42

    Challenge Math Experiment: Let's Prove Something

    This is an experiment. I thought of a way to bridge the gap between the usual challenge threads. Of course we could shorten the monthly period, but given that there are almost always untouched problems, more of them might not be the solution. Today we had a thread "Is math a language" by...
  12. dlxgains

    Moment of inertia project help- experiment 1: Bifiler Rod

    Homework Statement: So i need to find equations to help me with a bifiler suspension experiment in which i will use a rectangular drop bar as the oscillating object, also any help with the method of this experiment would be greatly appreciated. The end goal is to find the moment of inertia...
  13. Miles123K

    Products of Concentrated Barium Chloride Electrolysis?

    I did an electrolysis experiment with 1.6M Barium Chloride solution and the electrolyte turned black after the electrolysis. I am fairly positive that Chlorine was produced at the anode from the smell. However, Ba(OH)2 is colorless. I used graphite electrodes for this experiment. Does anyone...
  14. Adrian Tudini

    Actual yield determination by experiment

    Hi just one question. Can someone point to me some resources on how to calculate the actual yield under experimental conditions? thanks.Adrian
  15. F

    Drag coefficient experiment

    Summary: Hello, I have a task to calculate the air drag coeficient experimentally. I have a cone which I had dropped from height of 1.5 m and measured the time. Then I derived the equation of of velocity and acceleration but they are very complicated. Is there any simpler method? a=g-k/m*V^2
  16. S

    Who invented "observation, hypothesis, experiment, conclusion"?

    Who invented the description of the scientific method as "observation, hypothesis,experiment conclusion"? I'm aware that there are criticisms of this description and alternate descriptions. My question only concerns who first described the scientific method word-for-word in those terms. Was...
  17. Samanko

    Is the m/e Equation Valid When F = 0 in J. J. Thomson's Experiment?

    The text showed if Fnet = 0 (with F from magnetic fields and electric field), then v = E/B . And we can measure m/e (last equation in the image). My question is, by assuming F = 0, change in y should also be 0 , so the denominator of right side of the m/e equation must be zero. And the...
  18. Clay Gillespie

    Thought Experiment about light speed

    If we’re looking through a telescope at a craft we launched from Earth that is now passing Mars and send a radio signal to our craft telling it to turn on one of its lights on and it takes thirteen minutes for the radio waves to get from Earth to our craft how long will it take before we see the...
  19. neilparker62

    Insights Revisiting The Deuterium Lyman Alpha Line Experiment

    [url="https://www.physicsforums.com/insights/the-deuterium-lyman-alpha-line/"]Continue reading...
  20. SapientiaPT

    An experiment to measure the Speed of Light

    So, pretty much I want to make an experiment in order to get the speed of light. What I plan to do is to have a lantern in the dark(initially off) perpendicular to a wall, two sensors(one closest to the lantern and the other closest to the wall), then turn on the light making sensor 1 go off as...
  21. P

    B How does the LIGO experiment affect SpaceTime?

    I'm just a layperson with a keen interest a couple of notches above popular science. As far as I understand SpaceTime is an attribute where if you change one attribute (space or time) then the other attribute is affected. E.g. as you approach the speed of light, the time passing of other things...
  22. Ranku

    I Eotvos Exp: Gravitational v Inertial Mass Equivalence

    The Eotvos experiment tests the equivalence of gravitational and inertial mass. Some descriptions state that the experiment tests the equivalence between gravitational and centrifugal force, while others state that it is between gravitational and centripetal force. There is a significant...
  23. B

    I Need advice on vacuum / suction experiment

    Summary: Vacuum pump help I need advice on what type of vacuum pump would create max negative pressure in a very small area ( a space no larger than your pinky finger I guess) ? Maybe some kinda high suction low cfm pump? I don't know enough about vacuum pumps to know which type to...
  24. V

    I Who did this experiment with photons?

    This is the phenomenon of a photon simultaneously exist in many different spaces, experiment show that space does not exist and the distance is not real. This experiment bring a lot of sense in quantum research. I want to review again but forgotten the name of person that did it.
  25. N

    Exploring the Symmetry of the Double Slit Experiment

    I have no clue how to answer this question. I would imagine for (a) that half of the probability of total particles goes away with only one slit.
  26. G

    I Delayed-choice quantum eraser experiment

    In the Kim's experiments (see picture below) part of the downwards photons are involved in a quantum eraser and part aren't. In D0 (upward path) we see interference if the entangled photons (downward path) are detected in D1 or D2 and we don't see interference if the entangled photons are...
  27. A

    Bubble chamber experiment on a K− beam

    Hello everybody! Let's begin with the spin. Spin of the ##\Lambda## is ##1/2## and of the pion is ##0##: $$ \frac{1}{2} \otimes 0 = \frac{1}{2}$$ Since I know from the homework statement that ##L=1##: $$ \textbf{J} = \textbf{spin} \otimes \textbf{L} = \frac{1}{2} \otimes 1 = \frac{1}{2} \oplus...
  28. piyush_1903

    Exploring Frequency & Temperature: Theory & Experiment

    So, my apparatus consists of a basic wooden plank with a nail on one end and a guitar tuner on the other. I plan on using a heating lamp to control the temperature of the apparatus, which is placed inside an insulation box, and use a non-contact infrared thermometer to measure the temperature of...
  29. Abhimessi10

    Engineering Houston's piezoelectric method for finding the velocity of light

    Crystal acts as a diffraction grating.Although I don't know what that means.
  30. F

    A Madame Wu Experiment: Doubts & Reasoning

    Hi all, I have some doubts regarding the experiment of Madame Wu. I know a strong magnetic field is used to polarise the ##^{60}Co## nuclei, then we have an anthracene scintillator on the top of the sample which will detect the electron produced in the decay: ##^{60}Co \rightarrow...
  31. Kaushik

    Andrew's experiment on liquefaction of gases

    Look at the region from C to B. Why is the pressure constant here while the volume of the gas is decreasing? Is it the phase where gas to liquid transition is going on? What I know In the region from A to B, as the pressure increases the volume of the gas reduces. At C, the state of matter...
  32. M

    I Double Slit Experiment question

    I read in a book the following assertion. In a double slit experiment photons are passed through the slits and detected at the end plate. Each of the two slits has a quarter wave plate which alters the polarization of the photons that pass through it in a way different than the other QWP. Thus a...
  33. Graeme M

    B The Human Eye as a Detector in Double-Slit Experiment

    Trying to wrap my head around what the double-slit experiment is illustrating, it occurred to me that one could replace a mechanical detector with the human eye. I found that this was tested with what seems an elaborate test setup in 2016, and the result suggests that while an interference...
  34. hisacro

    Ampere's circuital law -- Monopole thought experiment

  35. x-vision

    B Speed of Light: Michelson-Morley Experiment Revisited

    If we assume that: the Earth has an atmosphere the Michelson-Morley experiment measured an isotropic speed of light inside the atmosphere We can conclude that the speed of light inside the atmosphere remains isotropic while the Earth is moving through space. But if we assume that: the Earth...
  36. A

    I Muon lifetime measurement experiment

    Hello everybody! I have a question regarding my physics laboratory at the university. I am performing the measure of muon lifetime. The setup is quite standard (coincidence measurement with plastic scintillators). My question is about the time resolution. I have tried to see if the time...
  37. D

    Why is a two-layered design recommended for heat insulation experiments?

    I'm doing some experiments on heat insulation with a model house (made of styrofoam, 3cm), heated with a 25W light bulb. In some papers I have read that it's important for the box to be two-layered, with only the outer layer being styrofoam and the thin inner layer consisting of material with a...
  38. DARKSYDE

    B Cherenkov radiation double slit experiment

    If a double slit experiment utilized photons from Cherenkov radiation under water, Would we expect the same results?
  39. Zahid Iftikhar

    Charge on plates in Millikan's Experiment

    When a capacitor is connected to a battery, it gets charged according to the voltage of the battery. If battery is disconnected, the charge stays on the capacitor. In Millikan's experiment used to find charge on an electron, when two plates are connected to a voltage source, they acquire...
  40. M

    B Experiment reverses the direction of heat flow

    I hope this is the correct section to post this but I found it very is interesting Link to original article: https://phys.org/news/2019-06-reverses.html Quotes from the article: "We investigated temperature changes in the spins of the nuclei of the hydrogen and carbon atoms. The chlorine...
  41. Iskak

    Double slit experiment wavelength of light used

    0.8m -> 800mm λ = (0.4mm*1.1mm)/800mm = 0,00055mm is it right? I am past that 3 months ago, forgot how to solve.
  42. J

    I Would this experiment disprove that consciousness causes collapse?

    A double slit experiment, is taking place. There are detectors, placed inside both of the slits. On the first run if a particle travels through one of the slits, the detector registers, that it has detected a particle, but doesn't specify which slit it has traveled through(to the conscious...
  43. angela6884

    B Creating an Interstellar Dust Nebula Experiment: Tips and Tricks for Success

    My experiment would need different composition of grains which would be ice, iron filings, and silicate shavings to act as the interstellar dust. I would drop these small particles(hopefully they will fall slowly) in a box and shut the lid quickly. Inside the box there will be a lightbulb acting...
  44. S

    B My particle simulation version of the Double Slit experiment

    I created this in java just a while ago.
  45. A

    Andrew's Senior Project: Copper Sulfate & Plant Development

    Hello, I'm Andrew and I'm in 12th grade. If you are interested, I would like to share a presentation showing the process, observations, results of an experiment showing the physical effects copper sulfate can have on early plant development. I, with much help from some intelligent members of...
  46. Shay Katzir

    B Is this an adequate thought experiment?

    I've been struggling to develop an intuition about Einstein’s relativity, without luck, until i invented my own thought experiment, to help me. Now i feel i have the intuition, but it leads me to a new misunderstanding, i hope someone here might help me clarify. My thought experiment involves...
  47. S

    B Double Slit experiment and the path of least Action

    Using the principle of least action can you figure out which path the photon took, or which slit it went thru given some initial condition. Or is this not possible and why.
  48. B

    Parallel Plate Pulsed Proton Beam Generator (Thought Experiment)

    I am trying to come up with a design for a device with which to generate a rapidly pulsed proton beam (on the order of 1 pulse per ms). My thought was to apply a 10 kV potential between two parallel plates (each with a hole in their center) and inject a steady stream of hydrogen gas through the...
  49. NP04

    Simple Harmonic Motion Experiment Problem

    I think you could try to solve for the forces based on when the spring falls from an incline at various angles theta, but I am not sure. Or spring potential energy? I'm really confused. Is there any other method? Could it involve using water and wave harmonics? (We learned waves and sound...
  50. S

    B Double Slit Experiment with a Medium in front of the slits

    Hi, I was wondering what would happen with the interference pattern if I had a medium with higher refractive index than air in front of the slits. Would the interference fringes become narrower?
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