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. H

    A Double double slit experiment and path information

    Hi Pfq My question is about this experiment: https://www.nature.com/articles/s41598-020-68181-1 (the link was given by DrChinese. If all the impacts are conserved no interference can be seen on the screens. but if we only take the impacts (Y, yi) where Y is always at the same position on the...
  2. L

    I Is the Fizeau-Type Experiment Valid for Measuring the One-Way Speed of Light?

    Can't see how in this experiment they claim to be able to measure the one-way speed of light: https://www.researchgate.net/publication/50908639_To_Re-Consider_the_One-Way_Speed_of_Light_UsingFizeau-Type-Coupled-Slotted-Disks Can you help me to debunk it? -- lightarrow
  3. dom_quixote

    I Atomic Clock Exp on Ballistic Flight: Proving Clocks are Accelerometers

    In the past, scientists have experimented with atomic clocks aboard airplanes in order to prove the Special Theory of Relativity. In our humble opinion, ALL watches are accelerometers. Effect observed in a chaotic pendulum in free fall: Too bad they didn't do the same experiment with an...
  4. T

    Venturi Effect based thought experiment

    The drawing above is regarding a thought experiment of mine. Air at ambient pressure is being blown through a convergent-divergent nozzle and in the throat section, a water filled enclosed container is attached through a tube. The water container has sufficient surface area for supplying...
  5. diogomcs

    I need an experiment about surface tension

    Summary:: Surface tension experiment Does anyone have an idea about a SURFACE TENSION experiment to present as university class work? An experiment that is not too "simple" and repetitive (like things floating under water), and that is well designed.
  6. Lynch101

    I Quantum Ball and Cup - Thought Experiment

    I'm sure most will be familiar with the well-known ball and cup trick. The dynamics of the game itself are unimportant, we just need to have the image of 5 cups with a single ball being revealed when the relevant cup is lifted. The Set-up Imagine a machine which has a conveyor belt coming out...
  7. H

    A Probabilities of couples of impacts - Bob and Alice and Young experiment

    Let O be where pairs of EPR particles are emitted to Alice on the righr and Bob on the left. the pairs have a constant total energy, a null total momentun and a null total angular momentum. Alice at a distance D on the right of O have a Young double slits device with a screen at D+ L . Bob has...
  8. A

    I The probability density function for the double-slit experiment

    I am desperate. I've scoured the web for the formula for the probability density function for the interference pattern obtained in the double slit experiment with both slits open. So I want to know the probability density function and not the intensity function. I prefer not to have references...
  9. hyksos

    A Call for experiment : Delayed Choice and Quantum Zeno Effect

    Under several historical experiments, measurement back-action has exhibited the ability the suppress a system's transitions to other states, especially when measurements are taken at a high frequency in time. This phenomena has become known as the Quantum Zeno Effect. In short, a quantum...
  10. H

    I Young's Double Slit Experiment: Is it Possible?

    I think that it is harder to describe the two slits Young experiment in terms of hamiltonian because the particle has a constraint: to pass through the slits. is it possible? thanks.
  11. M

    B Measuring Light Velocity Correctly: Thought Experiment

    Let there be a track 450,000 km long and a rocket 300,000 km long with a laser attached to the bottom of it's back end with a clock beside it, and a second synchronized clock attached to bottom of its front end. Both clocks were also synchronized with a track clock while the rocket was parked...
  12. L1ght

    I Question about the Which Way experiment & the detectors used

    Hello, I have a question about the Which Way / Quantum Eraser Experiment. I have tried my best to research online before coming to this forum to ask questions, so I apologize in advance if this question is novice but I have researched. I have been looking for a YouTube "video" of a real world...
  13. K

    I Help Designing a Resonance Box for Tuning Forks

    I got these tuning forks from someone. However, I do not have the resonant box for amplification of the sound. I decided to get it made so that I can experience the fundamental frequency (and other harmonics) more clearly. I am planning to provide this design. In summary, the box would be...
  14. M

    I Measurement problem in simple experiment

    I’m trying to understand the measurement problem using the simplest experiment I can think of--passing a particle P through a 50/50 beam splitter S, sending it down “path A” or “path B” with equal probability. Each path has a detector that can tell us if P was in that path. The detectors...
  15. J

    B Thought experiment (debate with friend)

    Thought experiment. Let's suppose I lay bricks around the entire Earth going up 50 miles in height. I am assuming this way there's going to be more bricks at the top than at the bottom right? Well... What If I was to get a football/soccer pitch (100meters in length and concreted with spirit...
  16. S

    I A thought experiment concerning determinism in quantum mechanics

    According to the uncertainty principle, when we measure a micro-object with a measuring device, we cannot predict what value the device will show. But if we knew exactly the wave function of this device, together with the wave function of the micro-object, could we exactly predict the result of...
  17. mishima

    Finding Piezoelectric Crystal Frequency for Coherer experiment?

    Hi there, I've been fascinated by using simple coherers to pick up the electromagnetic signal from a spark (in imitation of early radio experiments, for high school education). I am using a push button ignitor (piezoelectric crystal) attached to a simple dipole antenna for the transmitter. When...
  18. burakyildiz

    Projectile Motion Experiment: Results Too High?

    Hello everyone, I have a homework about projectile motion experiment and I threw small ball over the table and ball did projectile motion at the end of the table and ı recording this motion on motion tracker and motion tracker gave me acceleration of y component of ball as 14.02 m/s^2. But it...
  19. speedythespeed

    B Oberth effect on a slope - experiment idea

    I'm just curious if something like the Oberth effect on a slope is doable as an experiment. I have a picture of my idea of what to do just looking for some opinions.
  20. K

    I Determinism in a reversible polarizer experiment

    If light at a known polarization goes through a beam splitting polarizer that changes the light's polarization and then goes through the reverse orientation of that polarizer it will exit with the same polarization that it entered with. See the following picture: If the polarization state...
  21. Matt711

    B Q - Double slit experiment, delayed slit selection observation

    Do I see an interference pattern on a interference screen in Double slit experiment if there is a detector watching which slit photon went trough but the observer does not see the result of detector measurement? Thanks :]
  22. FMJalink

    I Proof of Special Relativity w/ Michelson–Morley Experiment

    Dear readers, Maybe someone can enlighten me on the understanding of the proof given by the Michelson–Morley experiment on the special relativity. Just as introduction to detail the setting: There are 2 coordinate systems A and B. A stands still and B moves with the velocity v along one of...
  23. L

    I Significance of double slit experiment?

    What is the significance of the double slit experiment? When I first learned about it I thought the human observer decided the outcome. But I guess a human observer isn't even needed and therefore a conscious mind is just as irrelevant. What does it prove that an outcome is neither one thing or...
  24. billyt_

    Misc. In desperate need for a DIY experiment that I can do at home

    I am doing a project for Physics at the moment, and I am really struggling to come up with ideas. By that I mean, I have plenty of ideas but none of them are really feasible for what I am doing, i.e., impractical to do at home (too much work in doing the actual experiment), or that the actual...
  25. S

    I Does the double slit experiment show waves collapse when observed?

    Do wavefunctions collapse when looked at? Or does observe mean something else? https://www.nature.com/articles/d41586-018-05892-6 This article is where my information is from, physicists talking about how our mind causes the collapse.
  26. I

    Lab Experiment - Puck Impact on Wall, Analyzing Force

    Please see attached image. This was a lab performed where a puck hit a wall shown on the page, the difficulty I’ve had is being able to see when and for how long the puck hit the wall as it is needed to find the average force in the system. Each dot on the page is 30milliseconds apart.
  27. MichPod

    I Stern-Gerlach experiment superposition vs mixed state

    Considering SG experiment, it is usually described as if an atom in the end of its path (but before being detected on the screen) is in the superposition state, say, ##|\textsf{spin up}, \textsf{upper path}\rangle+|\textsf{spin down}, \textsf{lower path}\rangle##. Some books (Feynman lectures...
  28. neilparker62

    I Online Experiment: Compton Scattering

    I recently thought it might be interesting to see if there were any online simulations or videos of Compton Scattering experiments. The search result yielded following: Given the standard equation: $$1-\cos\theta_d=\frac{E_0 \Delta E}{E_1 E_2} ,$$ we should get a straight line with gradient...
  29. S

    A The experiment for testing the CHSH inequalities

    I want to understand how an experiment is carried out to test violations of the CHSH inequalities. I have read Wikipedia and one popular book on quantum mechanics. The Wikipedia article is too short and incomprehensible to me; in addition, the description from Wikipedia and from the book is...
  30. C

    B Thought Experiment: Does Gravity's Compression Warm an Object?

    Thought experiment: (1.1) You have a homogenous object, made of one element, floating in space. (1.2) Gravity has completed the process of accelerating its atoms and molecules into the final state, such that the object is a crystalline sphere. (1.3) Gravity continues to act on the object, even...
  31. ayans2495

    Inverse-Square Law of Radiation

  32. H

    Experiment Exposing Tissue to Pulsed Electromagnetic Field

    Hai guys, My background is from tissue engineering more towards to biology. I am doing exposure of electromagnetic field to a human sample. I have been assigned to use the magnetic device with the information as followed: The PIC16F886 generates 150 microseconds (µs) of pulse frequency of 80...
  33. M

    I David Deutsch's Many Worlds Interpretation and the Double Slit Experiment

    David Deutsch is a well known proponent of the Many Worlds Interpretation. His argument seems to be that a single photon in the double slit experiment must be interfering with one from another world. It is commonly held by physicists that the the photon, as a wave going through double slits, can...
  34. VVS2000

    I Electronics experiment boards -- What experiment can I do with these?

    I recently got these electrical experiment boards to do some experiments but I am new to doing experiments with such boards. Can someone help? Thanks in advance https://ibb.co/zXTbNby https://ibb.co/tDjKrV0 https://ibb.co/JdCTgqY https://ibb.co/DDkGjbp
  35. N

    I Hafele-Keating Exp: Balancing SR Effects in Plane Ref Frame

    I have seen the "Hafele-Keating with the plane as reference frame?" thread (https://www.physicsforums.com/threads/hafele-keating-with-the-plane-as-reference-frame.767913/ ), but the replies do not seem to explain (to me anyway) what when taking a plane as a reference frame, balances the slowing...
  36. amjad-sh

    I Single-slit diffraction experiment and the conservation of energy

    In a single-slit diffraction experiment, a monochromatic light of wavelength ##\lambda## is passed through one slit of finite width ##D## and a diffraction pattern is observed on screen. For a screen located very far away from the slit, the intensity of light ##I## observed on the screen in...
  37. X

    I How does the Lota Bowl water experiment work?

    Hello! Can anyone help me understand why this experience works this way? If we plug the hole on the left side, the water does not affect the cup that has the hole on the bottom. However, if we let go of this hole on the left side, the water will start to pour into the cup again. Is the law...
  38. A

    I Electron two-slit experiment in classical electromagnetism

    Was there any study of this experiment in the context of classical electromagnetism? It is often claimed that such an experiment is impossible to explain classically, yet, the only classical model I've seen employed is Newtonian mechanics (bullets). The EM fields associated with the electrons...
  39. R

    B Does this experiment prove that light speed is actually faster?

    Some people thought light speed is actually instantaneous which can be demonstrated by doing an experiment involving a taut clothesline and two clothespins. On each ends of the taut clothesline, put one of the clothespins on both ends and touch one of the clothespin will make the other one at...
  40. A

    I Problem involving a sequential Stern-Gerlach experiment

    An electron beam with the spin state ## |\psi\rangle = \frac{1}{\sqrt{3}}|+\rangle+\sqrt{\frac{2}{3}}|-\rangle##, where ##\{|+\rangle,|-\rangle\}## is the eigenstates of ##\hat S_z##, passes through a Stern-Gerlach device with the magnetic field oriented in the ##Z## axis. Afterwards, it goes...
  41. Ghost Quartz

    I Math of Electron Double Slit Experiment

    I'm looking for a good derivation of the "wave" patterns in this experiment. I suppose that if wave-particle duality is an obsolete idea, there must be a derivation from quantum mechanics that gets close results. Thanks in advance
  42. B

    B When do marbles behave like a liquid in a beaker?

    If we place a cork in a beaker then filled the beaker with normal-sized marbles, the cork will remain stationary at the bottom of the beaker. However, if we continuously decrease the size of the marble, at a certain point, the marbles will behave like a liquid and the cork will rise to the top...
  43. K

    I Information traveling faster than light? (thought experiment)

    Let us consider a hypothetical scenario, where we are able to translate any mass at a constant speed of 10m/s w.r.t to a given frame of reference. For simplicity, we are going to assume that the object is at rest initially. Case 1 - Now, consider 2 points A and B at a distance of 10m, and our...
  44. P

    I Violation of Special Relativity Principle?

    From the michelson-morley experiment, if a clock were to measure the time period of light hitting the mirror and returning back, it would be 2L/c, where L is the distance between the laser nd the mirror. For a moving observer, the time period would have a factor of *gamma*, the boost factor...
  45. Boltzman Oscillation

    B Deriving formula for force by thought experiment

    Hi all, I was thinking punching a round ball on a flat surface and seeing how I could determine a formula for force from it. I thought the following: 1. The ball will go further the harder I punch and thus force must be proportional to displacement d. 2. Ball will go further if it is lighter...
  46. P

    B Is an experiment planned to discern determinism and randomness in QM

    I can remember reading something about a future experiment which alledgely could decide if there is an underlying deterministic layer governing quantum phenomena or if pure, empty chance rules suppreme (which I can't imagine). It had something to do with arrival times but I can't imagine how...
  47. C

    MHB Identifying if an experiment is a binomial experiment

    There is an example : A box contains 20 cell phones, and two of them are defective. Three cell phones are randomly selected from this box and inspected to determine whether each of them is good or defective. Is this experiment a binomial experiment? AND the answer is : NOT a binomial experiment...
  48. P

    B Question re photons/EM waves and the double slit experiment

    Not a physicist. Background is in electronics over many years. Have recently been "binge" watching youtube lectures on the "dreaded" QUANTUM MECHANICS by various people(Susskind, Feynman et al) and trying to comprehend the whole thing. While I can generally follow the lectures I must admit the...
  49. C

    B Is quantum superposition involved in the Stern-Gerlach experiment?

    This is how I explain it, away, now: Upon entering the magnetic field the silver atom's valence electron's electric field aligns itself at right angle/s to the magnetic field, the quickest/shortest way it can, as they are wont, to do, somehow, and the rest follows, naturally. And if U are...
  50. M

    B Double Double Slit Experiment -- Question about Variations

    emitter -> double slit -> double slit -> detector. Was an experiment ever made where two double slits are placed at some distance between each other? What kind of interference pattern would you get? What would happen if second slits were placed at the position where there is destructive...
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