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. DougFisica

    I Observables on the "3 polarizers experiment"

    Observables on the "3 polarizers experiment" Hi guys, I was analyzing the 3 polarizers experiment. This one: (first 2 minutes -> ) Doing the math (https://faculty.csbsju.edu/frioux/polarize/POLAR-sup.pdf) I realized that the process is similar to the Stern-Gerlach' experiment. Using spins...
  2. O

    I Observing a double-slit experiment

    Do I have the proper understanding of the following three double-slit experiment situations? #1 While a standard double-slit experiment is run via a Mach-Zehnder interferometer apparatus that completely lacks which-way detectors, can an ordinary human experimenter be present and watch that...
  3. M

    How to interpret the Standard Error in this experiment?

    Does the S.E. of $38.72 mean, I sould expect to win or lose up to $77.4 (2x S.E), 95% of the time?
  4. G

    Superdeterminism ruined the significance of DCQE experiment

    I keep thinking that the universe "knows" when, how, where these know-it-all (no pun intended) physicists did their experiment so all the results are not only consistent, but perfectly normal, nothing freaky about it. I'm no longer capable of thinking like a normal human being and subsequently...
  5. P

    A First findings from Fermilab's 'muon g-2' experiment revealed

    https://www.rearpost.com/post/fermilab-discovery-hints-new-physics
  6. deadbeef

    I Interference Patterns & Photon Paths: Exploring the Double Slit Experiment

    Hi. As i understand in double slit experiment photon can arrive at slits through different paths (longer and shorter) and it would still show interference pattern. My question is - if there was some path cutting device in a way of photon (on longest path after length that photon arrive at...
  7. Viky1147

    Calculate scaled down human model weight for practical experiment

    Hello, I need to scale down a human model by 1:20 i.e, i need a human model of 9 cm height scaled down. Help me calculate the weight of the 9 cm scaled down human model. Regards, Viky
  8. T

    I Large scale entanglement experiment

    This is the paper and here is the video. As far as I know, this is an entanglement related experiment done so far in such a large scale. I want to know whether entanglement related experiment has been done so far on a larger scale and what can be the possible use of such phenomenons.
  9. W

    B Symmetry of parity: Mistake in the experiment?

    Recently I saw this YouTube video from Veritassium about CPT -Symmetry: In this video an experiment of Prof. Chien-Shiung Wu is presented, which has proven that parity is not symmetric, by observing the emmition of electrons from Co60 atoms with synchronised spin. After thinking about this...
  10. S

    I Michelson-Morley Experiment: Objection Explained

    Could you please elucidate the below statement which is given as an objection to one of the possible explanation(earth drags the ether surrounding to it) for the negative result of Michelson-morely inferometer experiment? A second objection arises from the fact that a transparent object of...
  11. Justice Hunter

    B Thought Experiment : Try and get Alice to "0%" the Speed of light

    Someone asked a really interesting question on a comment thread somewhere's, and ever since, I could never really stop thinking about what the proper answer to it could be. It's a really basic question, but it unpacks a can of worms. The exact question I read was the following This question...
  12. StevieTNZ

    I Another Wigner's Friend Thought Experiment Paper

    https://phys.org/news/2021-05-future.html The paper in question can be found at https://www.nature.com/articles/s42005-021-00589-1 This thread is for discussion of the said paper.
  13. Shreya

    Plasma Experiment Involving Magnetic Fields

    I want to perform an experiment to show that magnetic fields can control plasma. (Can even be a slight repulsion) Please Suggest one. I have no idea where I can obtain plasma - I have access to candle flame (though it's not a proper plasma) & fluorescent lights. I have a permanent magnet (not a...
  14. G

    B Quantify Quantum Eraser Experiment

    I'm trying to grasp a quantum eraser experiment as described in a book I read. It helps me to put numbers to things, so my goal is to calculate the amount (intensity) of the light that demonstrates interference. The author describes a double slit quantum eraser experiment using polarized light...
  15. Sophrosyne

    B Twins Paradox Thought Exp: What Happens When Reunited?

    I have been looking through some of the threads about the twins paradox in relativity. It’s clear there’s a lot of confusion on this, and I am yet one more person very confused on this. So I was thinking about a hypothetical experiment, and I will lay out my hypothesis of what might...
  16. L

    B Some questions about Wheeler's delayed choice experiment

    Based on Wheeler's delay choice experiment, the following results of experiment1 can be achieved. Experiment 1, the light passed through the BS1, 50% of the light is transmitted on optical path A, and then passed through the polarizer P2(the polarization angle is 135°),and the polarizer P3 (the...
  17. P

    I Experience based on Millikan's experiment

    Hello! As I said in the summary, this is inspired by Millikan's experiment. Suppose you have 19 (closed) packages, all filled with different quantities of the same unknown object (which has a mass of m). You then weigh these packages one by one. How could you estimate the mass "m" of that...
  18. M

    Oscillating spring experiment uncertainty

    I know how to do the individual uncertainties but just not sure of the order.
  19. H

    Young's double-slit experiment - Bright fringes occurring

    I think the answer is E because each bright fringe is differed by a wavelength, in other words, one wavelength is equal to 2π. (For example, the first bright fringe is d * Δy/L = 1*λ.)
  20. Milsomonk

    A US Muon-g2 experiment - reading recommendations

    Hi folks, Hope everyone is keeping well. I've recently read the headlines of "strong evidence for new force of nature" pertaining to the Muon g-2 experiment. Interesting as I find the article in the BBC linked below: https://www.bbc.co.uk/news/56643677 I'd love to read some...
  21. R

    A Eddington's Experiment: Sources for Calculations

    Can anyone suggest me a few sources for his calculations?
  22. hugo_faurand

    Get electrical signal of a piezoelectric with ultrasound

    Hello everyone ! I'm working on ultrasound probes, and I wanted to measure the electrical signal generated by a piezoelectric device (a transducer). Here is a sketch of the experiment : The goal of the experiment is to compare the electrical signal of the piezoelectric cell and compare it...
  23. jackiepollock

    Young's Double-Slit Experiment

    As I searched online an answer suggested that the blurry effect might be a speckle pattern. However, it still hasn't explained the reason why when my body come near the pattern gets blurry.
  24. Rzbs

    Coriolis effect and water experiment

    Is the Uganda water experiment (that shows corilios effect on water drain) a scientific experiment or not? I searched but I couldn't find a final answer to this question. There are two opposite opinions, which one is correct? Or this argument is an open issue yet? Thanks for your replies...
  25. OneAverageGuy

    B Questions on the Michelson Morley Experiment

    I've heard claims the Michelson Morley experiment proves light moves at the same speed in all reference frames. However, after looking through the experimental setup, I do not see how they can make this claim. The entire experiment, from my view, was conducted in Earth's reference frame. His...
  26. C

    Wall made of Pendulum -- thought experiment

    If your house wall is made of pendulum or a ball attached to a string on top. It won't attract seismic forces. Whereas if the wall is fixed solid. It can attract seismic forces. What is the physics explanation of it? Is it because you try to deflect momentum or inertia? What is the right...
  27. HoneyBee

    Chemistry Finding rate constant from pressure change in an experiment

    Is there any way that I can find concentrations and then find the rate constant, k? And, using them, make an Arrhenius graph to find activation energy (including the catalyst)? Any help would be much appreciated. Change in pressure was found using a Vernier Gas Pressure Sensor. The starting...
  28. L

    A Thought Experiment: Aether Medium

    I would like to conduct a thought experiment. If some form of medium exists, what would it be made of? What form would any constituent parts take? Would those parts exhibit any properties? How would they function as a medium? What relation would the medium have with atoms and other particle...
  29. John_Dee

    Thought Experiment - Centripetal Force

    Ok, so we know that if one were inside a donut-shaped spaceship that is rotating around it's axis, that the passengers will experience centripetal force. It seems obvious to say that the ship is rotating relative to the nearby stars and planets. So far, so good. But... what if we removed all...
  30. Marilyn67

    A GBAR Experiment (CERN) - Genève

    Hello, My question concerns the (improbable but possible...?) results of the GBAR experiment at CERN which should resume in May 2021, according to my latest information. (delay due to Covid 19). Most scientists (and me too) believe that antimatter behaves the same as matter in a gravity field...
  31. K

    I Constant beam, both slits analyzed double-slit experiment?

    I keep seeing that it's assumed that photons interfere with each other, and there are other points of proof for this like destructive interference, etc., but I've never seen an experiment in which a constant beam is used but both slits are analyzed or the energy required for measurement is...
  32. B

    B Measuring a change in gravity - thought experiment question

    Imagine I hang a mass from the ceiling of a building using a rope. The mass is hanging 2m above the floor. Also tied "in line" with this rope, and between the weight and the ceiling, is a scale that measures the weight of the mass. Let's say the scale reads 10 Newtons. Now, between the...
  33. A

    Classical Home Experiment / Demo / Training Kit for students to use at home?

    Dear all, could you kindly recommend Physics Demo home kits (mechanics, Optics, Sound, Electricity/Magnetism) for secondary school level, to practice and learn at home? many thanks
  34. B

    B How is the measurement done for the double slit experiment?

    How is the measurement of which path the particle took done for the double slit experiment? When electrons are being sent through the slit. Or when photons are being sent through the slit. Is it an active process or a passive process? I haven't seen an explanation for this and perhaps this...
  35. R

    I Some questions about the photoelectric experiment

    Background: self-studying. Very confused. Here are some initial questions I have about the photoelectric experiment. Some more may pop up later. 1. The book says we know photons exist due to energy considerations (such as emission or absorption). They also say that this photon energy is...
  36. J

    I The Ensemble Interpretation and the Double Slit Experiment

    I am a big fan of Ballentine's book on QM and was reading the discussions about the Ensemble Interpretation. Although, I am not an expert on these matters I reject the idea of the wave function collapse as a fundamental postulate of QM. Instead, I've come to the conclusion that we don't...
  37. O

    Millikan Experiment Based Marble Mass Homework

    I arranged the masses in ascending order: 11.0 g 11.1 g 20.6 g 21.4 g 21.5 g 25.7 g 25.8 g 25.9 g 31.6 g 31.9 g I found the average mass of the marbles: 22.65 g I found the difference in masses of the marbles: 0.1 g 9.5 g 0.8 g 0.1 g 4.2 g 0.1 g 0.1 g 5.7 g 0.3 g I found the average of the...
  38. Someone_physics

    A Thought experiment in relativistic quantum mechanics?

    Background --- Consider the following thought experiment in the setting of relativistic quantum mechanics (not QFT). I have a particle in superposition of the position basis: H | \psi \rangle = E | \psi \rangle Now I suddenly turn on an interaction potential H_{int} localized at r_o =...
  39. ohwilleke

    B When Will Fermilab Release Its Initial Muon g-2 Measurement? [new update on August 10]

    Fermilab's E989 experiment is conducting the first precision measurement of the anomalous magnetic moment of the muon (muon g-2) since the Brookhaven lab did so fifteen years ago. It is currently collecting Run-3 data for this experiment, and said that it would be releasing preliminary Run-1...
  40. Adams2020

    The sources of error in a diffraction grating experiment

    In a diffraction grating experiment, what can be the sources of error and also what effect do these sources have on the unknown quantity (wavelength) in the experiment?
  41. Silverbeam

    Can an object maintain uniform motion without any external force?

    Hi, I’m new here and I signed up to ask for some help with a physics problem. I’m not trained, nor am I receiving training, in physics. I’m a bachelor of Geoscience student halfway through my course. The problem I have is with understanding and testing the law of uniform motion (I think that’s...
  42. PainterGuy

    B Double slit experiment with electrons

    Hi, Could you please help me with the queries below? Thanks in advance! Question 1: I was watching this video. Between 8:36 to 9:44 the following is said: "But only firing particle by single particle at this barrier with the 2 openings and by recording dot by single dot where each of those...
  43. davidbenari

    A Which condensed matter experiment PhD group is the most fun?

    This is going to be controversial and might even be taken down, but I think what I will say is absolutely true, and I'm sorry if it offends people. I'm applying for the second time to condensed matter PhDs. I was in a group that did a lot of device fabrication as part of their experiments and...
  44. L

    What Are the Results of the Millikan Oil Drop Experiment?

    mass: 1.57x10^-19 kg voltages: 400, 457, 384, 369, 400, 355, 369, 436, 384, 369 distance: 0.1m gravity: 9.81 m/s^2
  45. AN630078

    Thought experiment: How would ocean levels change?

    I am not too sure how to approach this, initially I thought it may be more of a calculus and related rates of change problem, i.e. finding an expression how the volume and height of water change with respect fo time. I do not know whether this is the right idea or how to progress any further...
  46. starkreactor

    I Thought Exp: Gen Relativity & Time Dilation

    I am trying to understand a thought experiment I just posed, which is: if an observer is traveling near the speed of light, and sends out two photons; one in the direction of travel and one in the opposite direction, how does general relativity account for time dilation? The photon "in front"...
  47. H

    B Gravitational signature of a photon in a double slit experiment

    I'm trying to think of a how the double slit experiment can detect a photon without interacting with it in theory. In principal (not reality of course) does a photon have a gravitational signature which could be used to detect which slit it traveled through during the double slit experiment...
  48. R

    B A question about the double-slit experiment

    In the diagrams illustrating the double-slit experiment, I see waves extending longitudinally towards the the metal sheet. What if the waves were modeled differently so that they extended transversely in the diagrams? I've got the feeling that this can say something different.
  49. S

    I The velocity of Pilot-wave and the Double slit experiment

    Hello, Its been a while since I'm trying to understand the concept of the pilot wave theory and it's relation with the deBroglie wave. What is the fundamental difference between the two? My confusion comes from the double slit experiment. The velocity of the deBroglie wave is c^2/v so I...
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