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.

View More On Wikipedia.org
Recent contents Top users
  1. quasar987

    I Thought Experiment Proving Newtonian Momentum Not Conserved

    On p.170 of French's book on special relativity there is this thougth experiment attributed to Lewis and Tolman (1909). It is about two individuals throwing identical balls of mass M at each other with identical speed. The balls bounce against each other and are caught again. See attached...
  2. olgerm

    I Can We Practically Measure the Gravitomagnetic Effect with Spinning Cylinders?

    I was thinking about an experiment to demonstrate gravitomagnetic effect. I did my calculations using gravitomagnetic model. It is not as accurate as general relativity, but GR should give similar predictions. I do not know if it would be possible to to this experiment in real life(are there...
  3. olgerm

    I Testing Gravitomagnetic Effect: Max Practical Results

    I was thinking about an experiment to demonstrate gravitomagnetic effect. I did my calculations using gravitomagnetic model. It is not as accurate as general relativity, but GR should give similar predictions. I do not know if it would be possible to to this experiment in real life(are there...
  4. LentilSoup7

    Home experiment - 'seeing' magnetic lines of force?

    Thought of doing this one years ago! Basically, I want to 'see' the magnetic force lines that surround a conductor when energized (with an alternating current). I appreciate that what I will see (or at least I am hoping to see) is the pattern formed by the iron dust in response the the field...
  5. MUZE

    Airship on Earth but a reentry glider on Mars

    Could a hybrid airship like spacecraft ever so slowly shed speed using Mars' atmosphere while remaining low orbit while buoyant enough to serve as a glider?
  6. A

    Number of maxima in Young's double slit experiment

    I honestly do not have any idea regarding this sum. Any help will be appreciated:)
  7. T

    I Single Photon Double Slit Experiment

    We're told that single photons passing through a double slit produce an interference pattern, but the act of observing which slit the photon passes through causes the interference pattern to show a simple ballistic pattern instead. But observing which slit the photon passes through necessitates...
  8. Davephaelon

    I Single photon double slit experiment

    My question is does the photon that is absorbed by an atom on the detection screen have exactly the same energy as the photon that left the 'gun' source? Hence, does the wave packet representing a photon lose some of its energy when it impinges on the double slit barrier, so that when the...
  9. S

    B Solving Doubts about Simultaneity Exp. in Special Relativity

    I'm reading about how the concept of simultaneity breaks down in special relativity. Here's the relevant paragraph: ----- Consider a photon source ##C_0## in a train car situated equidistant between detectors ##C_1## and ##C_2##. The source emits photons back to back. In a reference frame at...
  10. I

    Significant Figures with Experimental Values

    I was thinking of choosing 0.740, because it looks the most consistent with the other numbers because they all have a trailing zero. But then, in accordance with sig figs, 0.74 is the right answer. Which one should I choose? Thank you so much!
  11. G

    B Length Contraction Thought Experiment: Spot Mistake/Wrong Assumption

    Alice travels in a spaceship, which she measures to be L. The spaceship is moving with velocity v relatively to Bob. Alice makes a light beam traveling along the spaceship and measures the time interval it takes to go from one end to another, ΔtA. So, equation (1): L = c × ΔtA From Bob's...
  12. Steve Blandford

    I Thought experiment on photon entanglement

    This is a thought experiment I had with myself a couple of weeks ago. I have never seen it proposed. But please be kind I am not physicist but just a hobbyist. So this experiment is specifically for entangled photons. So here goes. I was thinking of something going faster and faster and time...
  13. F

    B Order of a dark fringe in Young's double slit experiment

    So the angular position for constructive fringes is d \sin \theta = m \lambda = (2m) \frac{\lambda}{2}, \qquad m=0, \pm 1, \pm 2, \ldots whereas for destructive fringes we have d \sin \theta = m \lambda = (2m+1) \frac{\lambda}{2}, \qquad m=0, \pm 1, \pm 2, \ldots I can see that ##m##...
  14. S

    B Is there a thought experiment to show that the speed of light is constant?

    I know the amazing thought experiment by Albert Einstein with the two light clocks. (The observer at the train station has a light clock and the person in the train.) It's amazing because you can even deduce the formula to calculate how fast the clock in the train goes. But this experiment...
  15. just dave

    B A thought Experiment in Time Dilation

    Ok so here's my idea,it came to me while watching a record album spin on my turntable(I believe it was Dark Side of the Moon). Technically this exp. could be done now but the results would take a while. You take a disc of some super strong material attach it to a ultra high RPM motor and put...
  16. K

    Real Fresnel diffraction experiment

    I'm wondering if I can perform an actual experiment to observe Fresnel diffraction. I would like to do it with a rectangular aperture and of course, visible light. What should its dimensions be? And from which distance from it can I expect to start seeing a decent diffraction pattern? I know I...
  17. Marcin

    I Time measurement in a double slit experiment with single photons

    Assumption: Screen detector is much closer to the slits than in "standard experiment" and the small angle approximation can't be used to determine the interference fringe maxima, but the interference pattern still occurs. Is it possible to measure the time of detection in such setup accurately...
  18. Marcin

    Double slit experiment with magnetic traps

    1. Is it possible to perform the following, modified double-slit experiment with single electrons/electron beam: The slits are separated in such a way, that each leads to a separate magnetic trap. The traps have oppositely directed magnetic fields, so that the electrons entering them move in...
  19. archaic

    Density from a viscosity experiment

    The body is a small ball. The experiment consists in dropping this ball, while varying the diameter each 3 trials, in a viscous liquid and measuring its falling time: ##D_i\sim t_1,\,t_2,\,t_3##. The equation we are using is: $$\frac{\Delta x}{\Delta...
  20. VVS2000

    Compound pendulum experiment to find the acceleration due to gravity

    In this experiment, I still can't figure out why the graph between time period and distance from point of oscillation is like that. Why does it first decrease and increase so steeply? I got the second part because it goes near the centre of gravity and time period becomes almost infinite there...
  21. Killtech

    I Stern-Gerlach experiment with a classical object

    I want to have a make/calculate a classical analog of the SG experiment within classical physics to understand all the relevant forces at play here. Within this context i would like to stick to classical physics only (yeah, I want it to compare to QM later but that is besides the discussion) and...
  22. arkantos

    I Question on the SG (Stern-Gerlach) Spin experiment

    During a SG experiment, the components N and S of the magnetic field are placed at the exact distance from the beam of particle?(or with precise approximation) What would happen if for example S is placed a little more distant from the beam of particle than N? Will we observe more deflection...
  23. VVS2000

    Moment of inertia (experiment)

    So in the above image, I intend to find the moment of inertia of that black rotating object which rotates due to torque which is provided by placing mass on the pulley. But the thing is that this rotating object is kind of like a ball bearing kind of system and even for a small torque it starts...
  24. SEYED2001

    I Relativistic energy equation applied to a double-slit experiment

    My question: How do the values for the velocity, momentum and energy of an electron in a double-slit experiment are altered by the observation? Probably,energy is altered. Given that energy is a function of momentum and velocity, either or both of these must have been changed. However, I am...
  25. UnderstandingQT

    B Questions about measurement devices in the double slit experiment

    How did you find PF?: Google Is it true that the devices that quantify which slit do NOT produce wave collapse unless they actually record the light measurements rather than just detect them without recording?
  26. L

    Faster than light thought experiment

    Hi :) I just had a (most likely totaly unoriginal) thought and thought I should try to ask someone who's thinkings on physics are somewhat more refined than mine. So after thinking twice about private messaging Mr Tyson and Mr Cox :) I decided to google 'physics forum'. So here I am with my...
  27. VVS2000

    I want to try an experiment related to mechanics -- suggestions please

    If anyone has an idea for an experiment or has any kind of manual containing experiments related to mechanics, that would really be helpful. If you have an idea like a new way to find moment of inertia of given object or anything like that, please do tell. I would really love to try it. Thanks
  28. Zaya Bell

    B Is a Spark Necessary for the Production of EM Waves in the Hertz Experiment?

    Hello, so I was reading bout the Hertz experiment in different text and they always say something about the Spark causing accelerated electric charge. So I was wondering, is the spark necessarily for the production of EM waves? If yes, why? Because as I recall, applying an ac voltage should...
  29. J

    B Mach-Zehnder Experiment: Wave-Particle Duality Demonstrated

    Can the essence o the Mach-Zehnder experiment be resumed as shown, to emphasize the analogy with the double-slit experiment? When the beams are brought together on a screen they form an interference pattern (no which-path inormation; wave behaviour). If the screen is removed and replaced by two...
  30. K

    I Effect of inserting an analyzer loop in the EPR experiment

    Given an EPR experiment such as the Alain Aspect 1982 test of non-locality using photons; if you modified the experiment so that the entangled photons first go through a analyzer loop (polarizer + inverse polarizer) before going to the polarizers in the experiment would you still see a non-local...
  31. Nikhil Rajagopalan

    I What is the significance of 54 volts in the Davidson Germer Experiment?

    In the experiment, a pronounced diffraction pattern is observed at an accelerating voltage of 54 volts. Beyond and below 54 volts, the peaks are not pronounced. What is the significance of 54 volts ? Why does the peak become less high below and above the specific value of accelerating voltage.
  32. K

    Static friction — Experiment pulling different blocks across a surface

    I know that I am supposed to use the equation I wrote, but how do I find the maximum force of static friction and coeffcient of static friction if none of them are given beforehand? I can't have to unknowns in an equation. We then did the same thing, the only difference was then to measure the...
  33. nmsurobert

    Gauge of wire to use in an induction experiment

    I'm setting up a Faraday/Lenz Law lab and was wondering if anyone had a suggestion on what gauge of wire I should use to get the best results. We don't have any wire here so I can't test it myself. Thanks.
  34. G

    Burned Bread Ash: A Magnetic Experiment for Iron Content in 7th Grade Science

    7th grade sciences class I was given the job to bring burned bread to class for a science experiment. My idea of burned bread was burned toast so we never got to do the experiment. Teachers idea of burned bread was ashes. That was many years ago. What class experiment can be done with...
  35. K

    I Sending Signal from Planet Near Gargantua: A Thought Experiment

    The other day my friend asked me a really interesting question regarding the scene from interstellar where they go down to Miller's planet, where every hour on this planet is 7 years of Earth time. He asked me if they were to send a signal to the spaceship where Romilly was, what would happen...
  36. V

    I Bell-type Polarization Exp: Uncorrelated Photon Pairs & End of Nonlocality?

    A very interesting experiment: Bell-type Polarization Experiment With Pairs Of Uncorrelated Optical Photons M. Iannuzzi, et al. in arXiv:2002.02723 [quant-ph] or Physics Letters A 384 (2020) 126200 The autor(s) conclude: "We may therefore understand that the measurement precedure adopted in the...
  37. K

    B Multiple Sequential Delayed Choice Experiment

    Hi all; This goes under the heading of experimental predictions... gone awry. Let me say from the start that I think I've got something wrong, and would have no problem having it pointed out to me. I'm a newbie, and I've been boning up on basic quantum physics phenomena on Youtube, and...
  38. Zaya Bell

    Testing How to perform a major physics experiment at home

    Hello there, I am a physics undergraduate and one trying to be very practical. I try to study a lot, to understand the principles and everything and get how all this knowledge came to existence. However, except for the little and not-very-modern experiments we carry out in our school I have no...
  39. F

    I Why Won't Observation in a 2 Slit Experiment Cause 1 Slit Diffraction?

    From what I understand, if the two-slit experiment is performed while observing a slit for particles, two distinct bands appear rather than interfering. This is a little confusing, as, from what I understand, diffraction is caused by measuring a particle's position (i.e. using a slit to narrow...
  40. Spinnor

    I Photon Double Slit Experiment: Visualizing the Guiding Field

    Does the following picture which I think shows the guiding field for electron in the double slit experiment have a corresponding image when the experiment is done with photons? Thanks for any help.
  41. KeesDeVries

    I Photon Bell Experiment, what happens in a single case?

    I am wondering what happens in the case of 100 entangled photons with a polarization angle of 0 degrees (or 0 and 90) that interact with Alice at 22,5 degrees and Bob at 45 degrees in a Bell Experiment. Do I get a count of 85 for Alice and 50 for Bob, which means a maximum coincidence count...
  42. A

    Understanding the math in the Michelson-Morley experiment

    [Mentors' note - No template because this post was moved from the Relativity forum] Summary:: I'm trying to make sense of the trig/algebra in discussing the experiment. This is an excerpt from the textbook Modern Physics (Thornton/Rex) meant to further explain the set up, however I'm not...
  43. R

    B A doubt on Rutherford's Scattering experiment

    Please refer to the image attached for the question.thanks.
  44. E

    Young's experiment - lowering the light intensity of one slit

    I think that what happens is that the amplitude becomes sqrt(2)/2A in the slit filtered, as opposed to A in the other slit. I suppose we will still get constructive interference from the slits, so the value (1+sqrt(2)/2)A will be reached as opposed to 2A in the usual experiment. However, the...
  45. J

    I Why does mass matter in Rutherford's experiment?

    Here it goes. I'm reading some notes on the Rutherford (gold foil) experiment and they first state what one should expect if the atom model was like the one described by Thomson (plumb pudding model). In order to somehow predict what the deviation should be when throwing alpha particles towards...
  46. S

    Wavelength used in double slit experiment

    m × lambda for bright = (m - 1/2) × lambda for dark so: 2 × 708 = 2.5 × second lambda Second lambda = 566.4 nm But the answer is 495 nm. Where is my mistake? Thanks
  47. C

    Young's double slit experiment

    I know that ydse is based on interference of light when it passes through an obstacle having almost same aperture as the wavelength of light. Also they should be coherent to have a constant phase difference at every point. But I don't get why the light beams should be parallel?
  48. K

    Diffraction Grating: Possible variables for Experiment

    For my High School Physics course, I have been tasked to design an experiment investigating the properties of a CD diffraction grating, and we MUST make a graph. Unfortunately, we only have two lasers of different wavelength, so changing the wavelength and measuring ##theta## would be a bad...
  49. F

    A Exploring the D0 Experiment: Proportional vs. Mini Drift Tubes

    Hi all, I'm reading an article describing the D0 experiment at Fermilab during Run II. Proportional drift tubes and mini drift tubes were used to detect muons: can someone explain me the difference between these two kinds of drift tubes? Thanks Federica
  50. JD_PM

    Galileo's tower of Pisa experiment

    a) Let's first analyse the plumbline. When it is in equilibrium, it follows from the projectile equation on a rotating Earth that: $$\mathbf 0 = -mg \mathbf k + \mathbf T$$ Thus, the tension in the plumbline is ##mg## and the string is parallel to the apparent vertical. Let's now analyse...
Back
Top