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. Z

    Rough overview of results from collision experiments

    I would be more of a theoretician, but recently I have been somewhat interested in trying to learn about recent results (last 30 years or so) in experimental high energy physics - about the implications or results from collision experiments and so on. I realize this is asking a lot, but is...
  2. D

    Experiments regarding Soundwaves and Frequencies

    At high school currently doing a unit on sound waves and frequencies. Any suggestions on experiments/investigations we could look at. We have microphones, speakers, guitars, strobe lights... Any Suggestions?
  3. D

    Time dilation/ light speed-thought experiments

    There are a few things bothering me about time dilation, its derivation, and special relativity. Einstein started with the assumptions that light travels at a constant speed no matter the observer or their frame of reference. He then details the light box experiment in which two observers are...
  4. R

    Tracking Particle Counts in Double Slit Experiments

    Hi, Is it possible to set up a double slit experiment where the numbers of particles being emitted can be counted and see if it is equal to the numbers detected at the screen? The particles should be Buckyball or other molecules where the energy can be made large compared to single...
  5. S

    Exploring Photon Trajectories in Double Slit Experiments

    In the aftermath of the recent Steinberg paper where they reconstruct average photon trajectories in the double-slit experiment, it has been pointed out several times that the reconstructed average trajectories strongly resemble the single-photon trajectories predicted by Bohmina mechanics...
  6. ZapperZ

    Marvel of Technology: The LHC, Machine, And Experiments

    The Chicago Blues Fest is going on this weekend in Grant Park right in the heart of downtown Chicago. If you are attending this, or are in downtown Chicago this afternoon, a short walk from the Blues Fest up Columbus drive just north of the Chicago River, you can attend this...
  7. C

    How are experiments affected when gravity's changed, compared to Earth?

    Hiii, If there's a simple pipe and pump circuit and the pump and water properties remain the same but we increase or decrease gravity, what happens? I know that in a closed pipe conduit with fluid flowing around, nothing would change because I think in Bernoulli's equation, as height is the...
  8. P

    Uncertainty principle and Einstein's thought experiments

    Recently, I have a look of the Einstein's thought experiments challenging the uncertainty principle. One of the experiments is the Einstein's slit. I found the description about it : "Consider a particle passing through a slit of width d. The slit introduces an uncertainty in momentum of...
  9. G

    Photon radius and affected energy in double-slit experiments

    Hi all, these questions have nagged me for years and I have never found a text or a paper that even addresses them. Regarding photon "radius", what is the maximum width that two slits can be spaced which still permits the double-slit phenomenon to occur? Would this be a valid method of...
  10. J

    Cardboard boomerang experiments and calculations

    I have to come up with an experiment using cardboard boomerangs that the rest of the class will do. The class then has to make calculations and test out the boomerangs to see if their calculations were correct. However, i don't know what kind of experiment I can have the class do with...
  11. J

    Determining particle spin in collision experiments

    How can high energy physicists determine the spin of a particle that decays before even reaching the silicon detectors? For example if a new particle turned out to have spin 3/2, how would it be distinguished from a spin 1, spin 1/2, or spin 0 particle?
  12. M

    Investigating the Motion of Floating Particles in Escaping Powder Experiments

    I am doing experiment about escaping powder. In this experiment I am immersing hot wire into the water and investigating the motion of floating particles. What is the importance of thickness of wire? And what do you think about other parameters?
  13. Z

    The Neutrino as a Majorana Particle and Ray Davis's null first experiments

    My interests are in astrophysics, so please forgive my ignorance of particle physics. I've just read Frank Close's book, "Neutrino"---excellent read, I'd recommend it---in which he points out that Ray Davis' first experiments to detect neutrinos from nuclear reactors (with no detections)...
  14. H

    Review Articles Bell Test experiments

    Hi Can anyone direct me to a recent review article of tests of Bell's inequalities. As recent as possible Thank you
  15. I

    How Did Mendel Conduct His Genetic Experiments?

    I'm trying to look at specific methods and results in how mendel did his experiment. The number of plants in the P generations, F1 generations etc that show the exact ratio between them. I'm finding it kind of hard to do so though. Can anyone help?
  16. W

    Exploring the Relationship between Force and Time in a Domino Effect Experiment

    Hi I did an experiment on dominos and came up with a set up. The set up: I placed 20 dominos one after another with a space of 3 cm in between each along a meter scale. The domino box had mobile top which placed right next to the dominos such that when upward force is applied it would hit...
  17. L

    F=μmg. How was μ calculated? Obviously experiments were

    F=μmg. How was μ calculated? Obviously experiments were needed. So, done the experiments, what's the exact conclusionology that μ is that much for that type of ground and that much for the other type of ground?
  18. N

    Cell Biology - Devising Experiments

    Cell Biology -- Devising Experiments Homework Statement I've included a picture of the problem to avoid confusion 2. The attempt at a solution I need to devise an experiment that would confirm the 3 statements. By experiements, it means something along the line of DNAase II sensitivity...
  19. S

    Nice Electrostatic Experiments

    Hello everyone, I am thinking of a nice experiment that can be done in high school laboratory. It is not obligatory for them to include calculations, they just have to be easily conducted without expensive equipment and relatively safe. The main purpose is to make students learn through...
  20. Femme_physics

    What are some great science experiments explained in a book?

    Hi guys, I'm looking for a book that will detail all the great science experiments (such as double slit, oil drop experiment, thompson's cathode ray) in a nice, detailed, chronological fashion, that can also be understood by non-science experts. Anyone got a good resource?
  21. D

    Heating Elements for Experiments

    Hi, As part of my final year project I have to heat air within an exclosed environment (i.e. a 1m x 1m x 1m insulated box) to test the effectiveness of using phase change materials to regulate ambient air temperature. To do this I need to slowly heat the air inside the box at a rate that...
  22. C

    Are there any experiments that supports de broglie-Bohm theory?

    There are a lot of experiments to disproof hidden variable theories with Bell's inequalities (local) and Leggett's inequalities (non-local). But de broglie-Bohm theory (dBB) survives from all of them. Also I know there is an Quantum Equilibrium Hypothesis says that everything that disproof dBB...
  23. R

    Which Experiments Proved CP Violation in Particle Decays?

    Hi, I'm currently producing an undergraduate poster on CP violation and I have a few questions: - Was K0 -> \pi++\pi- the decay which proved CP violation in the 1964 Fitch/Cronin experiment, or was it oscillations between K0 and \overline{K}0, or both? (Answered) - How were the decays in...
  24. StevieTNZ

    Macroscopic Quantum Coherence & Macrorealism experiments

    Has anyone performed experiments regarding macroscopic quantum coherence (superposition of and macroscopic object)? What about testing if macroscopic objects obey macrorealism, or whether QM prevails? Links to articles or experiments would be apprecited.
  25. N

    Is this diagram i have made relating to david hahns experiments correct?

    hi, see my diagram here, is my "neutron gun" correct, or have i made mistakes? what will happen to the "uranium powder"? will it eternally grow more radioactive, or will it at one point transmutate? http://alf.000space.com/neutron%20gun.png thanks for your help, alf.
  26. F

    Exploring Quantum Mechanics: Interference Experiments with Entangled Particles

    Hi, This is my first post here. I have done some reading on quantum mechanics and am curious to know more. I know about the double slit experiment and the interference pattern produced. I have also read of entangled pairs. My main question is: If you have a pair of entangled...
  27. V

    What Are Some Inexpensive Physics Experiments to Revive a University Club?

    Me and a couple friends are trying to resurrect the old physics club at my university and could use some cool inexpensive experiment ideas to try and boost attendance and have some fun. Any ideas?
  28. H

    Einstein & Hawking: Delivering Theories Without Experiments?

    Suppose I am simple man, who studies in home and read some scientific journals . Could I be able to deliver some theories(and would it be possibly correct ?. Would I have to be engaged in big laboratories consiting super computers, advance telescopes etc? How was eeinstein became able to...
  29. G

    Quantum Gravity Experiments: Proposals & Models

    Have there been any proposals of plausible experiments for any of the heavily studied Quantum Gravity models?
  30. P

    Exploring NMR: Questions on Modeling and Experiments

    Hello all, I have questions regarding my understanding of NMR and the mathematics of it. If anyone would take the time to read this, I would very much appreciate it. Please bear with me, I am a beginner. Thank you! First, there is the question on how to model this phenomenon. Up till now I...
  31. L

    Force Distribution in Wind Tunnel Experiments

    Hi physics peoples, [for the tl;dr peeps: is there any point plotting a force distribution when I already have a pressure distribution, aren't they essentially the same thing?] I've been doing wind tunnel experiments on structures for my final year engineering project, my supervisor (who I...
  32. B

    Top 5 hallmark experiments in physics

    What would you say are the top 5 "hallmark"/landmark experiments in physics?
  33. P

    Unraveling the Mysteries of Muon Experiments

    Hi guys, just wanted to ask a question related to muon experiments (and all other which can be presented this way) to get some things clearer. Ok, here goes: We have lots of muons traveling towards Earth. Their mean lifetime, measured in lab conditions (at rest) is 2.2µs. Their...
  34. B

    Time loop thought experiments

    Hi, I have some questions about time travel. My understanding is that it is an accepted theoretical consequence of General Relativity. If the scenarios I'm describing are too ridiculous then perhaps analagous microscopic scenarios would be more palatable. Consider these scenarios: Scenario...
  35. J

    Exploring Nuclear Fission & Fusion: Experiments & Theorists

    Homework Statement For my essay on nuclear fission and fusion, I have to discuss some experimental evidence for nuclear fusion. I also need to find info about scientist that are responsible for developing the theory behind nuclear fusion. I am having trouble find info on these aspect. Any...
  36. K

    Distinguishing Two Experiments With Equal Density Matrices

    For example, a esemble of 50% spin up and 50% spin down electrons, the other of 25% spin up,25% spin down, 25% x direction spin up and 25% x direction spin down. The density matrix is identity matrix for both(correct me if I'm wrong), is there any way to distinguish the two experimentally?
  37. H

    Why do we still need real world experiments?

    We have windtunels to measure air flow, Erlenmeier flasks for chemical reactions, and so on. Why not just load the geometry of the aircraft into a computer simulation and get the results from there. It is much more cost efficient and you can manipulate things faster and easier. For chemical...
  38. E

    List of Electron Double Slit Experiments?

    I've been reading some papers about electron double slit experiments, including the one by Jonsson which seems to be the most detailed and well written so far, but I've only been able to find about five papers total. Jonsson was one, then a 1989 single-electron double slit experiment, and a few...
  39. E

    Resolution in scattering experiments

    Here are two exercises: 1. ) The proton radius is 0.8fm. What energy electron beam do you need for this resolution, if the target is liquid H2? 2.) A pion radius is 0,65fm. What energy pion beam do you need for this resolution by scattering on the electrons of a stationary target(pi-e...
  40. S

    Weird Results from Neutrino Experiments

    Recently, the MINOS detector has shown results that call into question the symmetrical properties of anti-neutrinos with respect to neutrinos: http://arstechnica.com/science/news/2010/06/antineutrino-masses-throw-physics-a-curve.ars More strange results came from MiniBooNE...
  41. A

    Why are reactor experiments measuring theta13, not theta12?

    The question I have came from a talk I saw about the MINOS experiment. They say they can measure theta13 from their beam of mostly muon neutrinos by measuring electron neutrino appearance. Why would this not involve theta12? Is what is happening that the dominant chain is muon neutrinos...
  42. I

    Deducing the Elementary Charge from Milikan's Oil Drop Experiments

    Homework Statement In an early set of experiments, Milikan observed that the following measure charges, among others, appeared at different times on a single oil drop. What value of elementary charge can be deduced from these data? 1) 6.563 x 10^-19 C 2) 8.204 x 10^-19 C 3) 11.50 x...
  43. J

    Home Quantum Physics Experiments

    Hello, Does anyone know of any quantum physics experiments that can be preformed at home. All of the experiments I've read about seem to require expensive equipment and precise alignment. Any information would be appreciated. Thanks.
  44. D

    Some Thought Experiments (simple ones)

    1. A clock is placed on a light beam. Will the clock stop? If yes, why doesn't the beam stop altogether? 2. A ruler is placed on a light beam. Will it's length shrink to zero? Why/Why not? 3. A massless particle is placed on the beam. What would happen? 4. An electron...
  45. L

    Calculations from photoelectric experiments.

    Homework Statement In a photoelectric experiment using a sodium surface, you find a stopping potential of 1.85 V for a wavelength of 300 nm and a stopping potential of 0.820 V for a wavelength of 400 nm. From these data find the following: a) a value for the Planck constant b) the work...
  46. F

    Can Flat Space Experiments simulate the Big Bang?

    I'm wondering, now that the universe has expanded and is now pretty much flat, can any experiment we do tell us what might have happened during the Big Bang, when the universe was still small and tightly curved? It doesn't sound like the same situation. The results we get today travel meters or...
  47. P

    Experiments on Greenhouse Gases

    Note: This isn't intended to be a Global Warming thread but rather a Greenhouse Gases thread (they're not the same thing), so please let's not talk about Global Warming because I don't want it closed. I'm very interested on any feedback or thoughts anyone may have for my experiments...
  48. B

    Radiation risk from school experiments?

    We recently did experiments in school using sources of Radium-226, Americium-241 and Strontium-90. They all had a strength of around 185 kBq. In some of the containers there was only a very thin piece of foil keeping the material inside, or so I was told. Since the experiments I've kind of been...
  49. A

    Why Don't Photons Get Absorbed in Double Slit Experiments?

    hi maybe I'm asking a stupid question, I'm a layman, and i didn't succeed to google out the answer. while performing single photon double slit experiment, why the photons don't just get absorbed in the separation between the slits, like they do in the screen behind. and consequently...
  50. J

    Factors affecting inductance experiments

    I am about to do an investigation on the 'factors affecting inductance.' It would be brilliant if anyone had any ideas on experiments I could perform to investigate the factors affecting inductance. Thanks for your time.
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