What is Experiments: Definition and 475 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. jedishrfu

    B Things to try while watching the solar eclipse

    We can: 0) watch the eclipse unfold with our ISO approved eclipse glasses 1) listen for insects chirping as they think night has fallen 2) make a pinhole camera from a shoe box 3) wear red and green clothing to see how our perception changes in the twilight of the eclipse (to witness the...
  2. D

    B Layman's summary of water telescope experiments

    In Layman's terms, what did Klinkerfues experiment show, what was he trying to test and what was conclusion. Same questions for Airy's follow up experiments in 1871 and 1872. Thanks !
  3. P

    What are you supposed to show when you have no data to present?

    Like when you're doing tons of things but it's mostly preparation for experiments and it's not really working so it's slowing experiments down. There's tons to talk about but there's really nothing to show anyone in terms of a powerpoint.
  4. G

    I Some doubts about determining experiments

    Imagine experiment is such as I drop a ball from some height vertically only. What’s the right way to do 2nd experiment in order to check homogeneity of space. Way 1: I move a little bit and drop the ball (same height, it’s just I moved - ball as well, but not in terms of height) Way 2: We...
  5. yucheng

    A How are quantum optical experiments designed? ;)

    inspiration: How does one predict the effects of small modifications (ordering of optical devices etc)? https://www.physicsforums.com/threads/the-experiment-of-kim-et-al-1999-with-small-modification.1047803/ In chapter 5 and 6 of A Guide to Experiments in Quantum Optics, the authors deal with...
  6. H

    B Is there a resource that discusses wave collapse experiments?

    I would love to read about the different experiments that deal with the collapse of the wave functions and related items. Maybe summaries, I definitely don't want to get into math or anything. Just what causes it to collapse, what doesn't, can it partially collapse, can it collapse in these...
  7. A

    I Analysis of data from previous experiments

    Has it ever happened that after a discovery, data from previous experiments were analyzed and it was noticed that there was already some evidence of the phenomenon in question?
  8. K

    I Updates on the experiments X17

    your thoughts on this -- Status of the X17 search in Montreal they'll verify or refute a clear signal after about two weeks of data taking with a 2 μA proton beam if Montreal Tandem accelerator confirm X17 a clear signal after about two weeks of data taking with a 2 μA proton beam would you...
  9. J

    I Exploring Entanglement Through Laser Light Mixing Experiments

    https://quantum.phys.lsu.edu/old-website/seminars/abstracts/Kaushik10.pdf I have discovered an experiment in the link above where you get NOON entangled states by mixing classical laser light with quantum light from SPDC. But I cannot understand the mathematics behind it. Can you explain it to...
  10. A

    A Current status of FR type Thought experiments

    Recently I've seen many fixed FR(or Wigner's friend) thought experiments.For example, https://arxiv.org/pdf/2011.12716.pdf is a zero-cited paper that presents a strenthened version of FR ,and claims to have solved its weaknesses.The author claims that it supports the idea that the "C"(for...
  11. sol47739

    I Postive rays in cathode ray tube experiments?

    I read in the following book A history of the sciences by Stephen F. Mason. About the discovery of the electron the write what I attached in the picture. I wonder what do these positive rays traveling in the opposite direction they talk about consist of? Some ions or what? I understand that the...
  12. StanislavD

    A Experiments for temperature dependence of persistent supercurrent?

    Imagine, in a mercury ring (superconductivity below Tc=4.15 K) we establish a persistent supercurrent. Then we organize temperature cycles (T-cycles) in the cryostat, from 3 K to 2.5 K and back. According to the BCS theory of superconductivity, the pair density decreases at warming, i.e. a not...
  13. tbn032

    B Exploring the Alpha Particle-Electron Interaction in Gold Foil Experiments

    My current understanding: The mass of alpha particle is approximately 7340.6 times higher than the mass of electron.in the gold foil scattering experiment the deflection of alpha particle due to electron is approximately zero. The reason that is given is that since the electron is much lighter...
  14. DennisN

    Physics experiments that changed the world (video)

    If you enjoy both physics/science and history like me, you may enjoy this video from the Royal Institution. It's about groundbreaking experiments (no theoretical physics); X-rays, particles etc. I'm only 45 minutes in so I haven't seen the entire video yet, but I wanted to share it...
  15. A

    I Are Lab Experiments with Strong Magnetic Fields and Plasma Expensive?

    What is the cost of lab experiments? I do understand that it depends, but let's say it's the cost of experiments conducted in a western country involving 1) strong magnetic fields; 2) plasma. Also, can one find price lists for such things online? Thanks.
  16. ohwilleke

    A What New Experiments, If Any, Would Help Determine Light Quark Masses?

    The experimentally measured properties of protons and neutrons are known with exquisite detail. Our data is not quite as extremely precise, but still very good more other baryons and mesons with light quarks (u, d, and s) as valence quarks, such as pions and kaons. Yet, on a percentage basis...
  17. L

    B Wanting to do some impact force experiments

    I have 3d printed some 25mm cubes all with the same parameters. what i want to do is take some different weight dumbells, and drop them all from half a meter onto a cube. My goal is to collect data and see at what impact force the cube fails. For me, failure will be when layers break apart, not...
  18. M

    I Do Bell Experiments Show Local Overlap of Wave Functions Before Measurement?

    Consider experiments that demonstrate violations of Bell inequalities. I'm wondering about the spatial extent of the wave function of the particles BEFORE measurement. I assume the spatial extent is "very large," and my main question is whether they overlap. If the wave functions do overlap...
  19. ThiagoMNobrega

    B Low magnification, high resolution, experiments on photon sieves?

    In the video above we can see the wave like patterns. The microscope on the video, used on the experiment, has a low quality and a low magnification. If anyone has a scientific article or a video source for such experiment with low magnification but with a high quality of definition it would be...
  20. G

    A Thought experiments suggest problem with published work

    A recent preprint ( https://arxiv.org/abs/2112.15157 ) seems to imply that the focussing properties of an optical system can depend on the bandwidth of the sensor, and even on that of the associated electronics! It is argued there that if the ‘frame rate’ of the sensor is very high, photons...
  21. K

    I Finding ##S_x## eigenstate using experiments

    Quantum mechanics, McIntyre, pg 62 For above spin ##1## Stern Gerlach experiment a set of results is "## \begin{array}{c} \mathcal{P}_{1 x}=\left.\left.\right|_{x}\langle 1 \mid 1\rangle\right|^{2}=\frac{1}{4} \\ \mathcal{P}_{0 x}=\left.\left.\right|_{x}\langle 0 \mid...
  22. ergospherical

    Testing Presentations on experiments / lab work

    I'm trying to prepare a slideshow presentation of some lab-work we've undertaken. It's to be around 15 minutes in length and comprise of a few different (but related) experiments. I would like to ask if anybody knows of one or a few "exemplary" experimental physics presentations (on YouTube...
  23. A

    B Problems I Have With Electrostatics and Pith Ball Experiments

    As a preliminary note, most people flex about how dumb questions and then continue to school and scold curious minds. Instead of taking a demeaning approach I just ask for respectful insight to quench curiosity. I will 1) explain the experiment as I know it to be, 2) explain what I have been...
  24. MathematicalPhysicist

    A What possible experiments will falsify String Theory?

    Or will confirm its predictions? As far as I can tell, you can only raise the bar on the energies required from the accelerator, but you cannot give an upper bound, where beyond it the theory is doomed... This isn't science... we might as well say we need infinite energies. 🙃
  25. G

    B What experiments confirmed the constant velocity of light?

    What other experiments, besides the M&M experiments confirmed the constant velocity of light? Thank you in advance for the response.
  26. amjad-sh

    I Calculating Intensity in Single Slit Diffraction Experiments

    In a single slit diffraction experiment, when we want to calculate the intensity of light on a screen located very far away from the slit, usually Huygens' principle is adopted as a model to perform the calculations. It is assumed that the width of the slit consists of an infinite number of...
  27. M

    A Why low temperature is better in many precision experiments?

    Hello! In many precision experiment, especially those overlapping with quantum computing techniques, such as trapping a few ions in a Paul trap, they use cryogenic systems (around 1K). I am not totally sure I fully understand the advantage of that, compared to room temperature. For example, a...
  28. K

    A Experiments with diatomic molecules

    Hello! I was wondering if there are papers presenting ideas of experiments (ideally searching for new physics, but not only) involving diatomic molecules, that were quite out of reach when they were published but we might have the technology to implement them with the current technology (or in...
  29. Dale

    I Distinguishing Einstein Cartan from GR: Experiments

    Are there any experiments either already performed or even simply proposed that could be used to distinguish Einstein Cartan gravity from GR? My current understanding is that they are the same in vacuum, and only differ in matter. In matter the Einstein Cartan metric can have torsion, unlike...
  30. anorlunda

    Could stopwatch errors change race results, and physics experiments?

    Ay ay ay. Here's yet another worry to give you headaches.
  31. B

    B Exploring Relativistic Thermodynamics Experiments

    In most experiments of SR, we look at atomic and subatomic particles or the frequency of EM radiation. The Haefele-Keating experiment looked at the resonance of cesium atoms stimulated by a certain EM frequency https://en.wikipedia.org/wiki/Hafele–Keating_experiment The Ives-Stillwell...
  32. A

    Experiments to do in deep space at 40% of c

    Hi there, first post here! I'm working on a story and at one point there is a ship traveling at 40% of C. The characters are on a long trip, fifteen years or so, I'm wondering in a ship far from any star system going at a % of C, what kind of interesting experiments could one do. The ship has...
  33. X

    B How to Compile a Report on Experiments: Resources & Tips

    Hi, I have to do an exam (lasting 3 hours) where it is required to perform a very simple experiment. The test is graded, obviously, not on the experiment itself but on how you compile a report on it, tables, graphs, error proagation, data analysis, etc... all stuff I'm definitely not good at...
  34. hyksos

    A The most striking example of vacuum fluctuations affecting experiments

    This is a question for experimentalists working in Condensed Matter Physics. What do you think is the most striking example of QFT vacuum state fluctuations affecting the results of an experiment? I have vague memory of reviewing some abstracts about quantum criticality in cuprate...
  35. R

    B Questions about double slit experiments

    Firstly I’m just an interested layman who only started delving into QM and physics later on on life. So please forgive my ignorance. One of the things I’m trying to understand better is the wave / particle duality nature of objects. In the classical set up where single electrons are fired one...
  36. chucho11028

    Motion in one dimension -- Experiments with a Hot Wheels car rolling down a ramp

    Hello This is not a homework, this is my own experiment to understand how the motion works. Please, follow my question here below: I have a hot wheels race with a slope with 10 degrees where I use a small car which departs from the top to the bottom. I have taken 5 times the time to get an...
  37. D

    B 2D-cross-double-slit experiments for understanding quantum world

    How did you find PF?: gmail The regular double-slit experiment is the "the basic Mystery" in quantum (Feynman). now I have done several cross-double-slit experiments with different configurations, My question is: how photons “sense”: (1) which slit they pass through; (2) what photons they...
  38. DarkMattrHole

    I Entanglement of Electrons Through Experiments: What's Possible?

    My understanding is that an elementary particle A becomes entangled when it interacts with another particle B, sharing symmetrical properties with particle B, until particle A interacts with another particle C, whereupon particle A becomes entangled with particle C. When an electron gets fired...
  39. H

    Please Explain My Polarized Light Experiments

    I wanted to filter out reflections from glass. So I bought a camera with a "circular polarizing filter." It filters out polarized light, adjustable for orientation. The result confuses some cameras, so it also has a second stage which induces circular polarization. The results were...
  40. S

    A Exploring Bragg/von Lau Scattering: A Discussion of X-Ray Experiments

    Overview of thread: 1. Quick derivation of bragg scattering 2. Discussion of modern xray experiments as they relate to bragg/fraunhofer 3. Summary of points. Bragg/von Lau Scattering: (I will be following Ashcroft if you want to sing along, pg 98-99) Imagine you have light incident on some...
  41. N

    I Unconventional methods for pumping down a vacuum chamber?

    Hi all, I'm not sure if this is the correct space so please let me know if it belongs elsewhere. I've always been very interested in engineering. In my spare time, I tend to think about a lot of unconventional ways of doing stuff because I'm of the mindset that there's always new things to...
  42. C

    Is there a difference between Faraday’s induction experiments?

    Faraday first demonstrated his law of induction by showing that when he created a current in one wire coil it created a second current in a second coil. Another experiment showed the same effect. When he moved a magnet through a wire coil, it created a current in the coil. My question is this...
  43. Souma

    I Can the "same" particle be used in different experiments?

    When a particle is observed, an interaction must happen between it and the measuring apparatus. But, this interaction mostly (if not always) leads to the loss of the particle, and hence, can't be used again to do the same experiment or different experiments. I know that particles are identical...
  44. R

    Relativistic speed accelerator for physics experiments in a capsule

    Is it technologically feasible today or in the near future, to accelerate in outer space a ~0.1 gram physics experiment lab, inside a cyclic accelerator and shoot it in a straight line at a constant speed of 5%-80% of the speed of light? That miniature capsule, must include all that is needed...
  45. R

    B A doubt on Thomson's Experiments to determine the value of e / m_e

    By carrying out accurate measurements on the amount of deflections observed by the electrons on the electric field strength or magnetic field strength, Thomson was able to determine the value of e/me as... e/me = 1.75 10^11 C kg^-1 would this be a correct understanding of this para- "This para...
  46. B

    Finding the Acceleration of Gravity from these Dropped Ball Experiments

    Did not know where to start so I tried A= v/t to find velocity then plug into equation to find g, but i got a huge g.
  47. A

    What Are the Essential Experiments for Studying a New Planet?

    Summary: I am looking to compile a list of experiments that would be conducted on a new planet to learn about it. Hi, I am trying to compile a list of experiments that would be conducted on a new planet. I'd like to categorize them as such: Simple field experiments that could be done with...
  48. DrChinese

    A How do entanglement experiments benefit from QFT (over QM)?

    I should first acknowledge 2 important points. I don't read papers on QFT, and therefore barely know how to spell it. And second, although I read many papers on entanglement (theory and experiment) I don't know if I have ever seen much reference to anything I might label QFT (that being...
  49. entropy1

    I (In)dependence in entanglement experiments

    If an entanglement experiment, whereby an entangled pair of particles is measured at both ends, is independent of the next entanglement experiment with another pair of entangled particles, how can there be a correlation? It seems that each independent run does not influence the next run, but...
  50. 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...