Experiment Definition and 1000 Threads

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. A

    Young's double slit experiment with two sets of slits

    1. The problem statement, all variables and given/known da Homework Equations Interference minima is asinΘ=nλ/2 where n=1,3,5,7... [/B]The Attempt at a Solution Putting ab/(2sqrt(b^2/4+d^2))=λ/2 for first order minima And solving for d I get (b/2)*sqrt((2a/λ)^2-1) in which only the 2 factor...
  2. Lukeblackhill

    Galileo's Experiment with an Inclined Plane

    Morning mates, I've peformed Galileo's experiment with inclined planes, using a ramp of 88cm (divided in 4 parts of 22cm), inclined by a height on the right-edge of 4cm. I've measured the following, 1/4 of the ramp (22cm): 1.75s (error of 0.1s) 1/2 of the ramp (44cm): 2.70s (error of 0.1s) 3/4...
  3. J

    Magnetostatics experiment flowchart - How can I improve this

    Homework Statement I'm attempting to write a FORTRAN program that calcuates the magnetic field, B, at any point outside of a bar magnet. I will be using a simple first order euler scheme for numerical surface integration. Homework Equations Here is the exact method I will be using...
  4. A

    I Why do we need a theory to replace the Galilian composition of velocities?

    In Michelson Morley experiment we use a moving mirror to reflect light and then we find out that light moves with c regardless of the speed of the mirror. My question is why do we need a theory to replace the galilian composition of velocities?i mean this can be explained by saying that...
  5. A

    I Learn Michelson Morley Exp: Best Books Explaining Light's C Speed

    I want a book that explains everything about Michelson Morley experiment. The one that says light moves with c regardless of the speed of the source and also the one that says light appeared to move with C for all observers.
  6. SuchBants

    I Cavendish experiment to determine G

    I'm doing the experiment for a project using a setup as so: https://imgur.com/a/7vfg2 In the derivation of the formula I used the amplitude of the oscillation on the ruler of the laser, basically taking it as the arclength of the arc drawn by the laser spot as the bar rotates inside the...
  7. S

    B Delayed Choice Quantum Eraser Experiment Results

    Hello everyone. I want to ask some questions about dcqe experiments results which are bugging my mind. It is so hard to find reliable sources in my native language so I'm here. Also sorry for my scuffed english. Assuming we all know the famous experiment setup, I am directly passing to the...
  8. berkeman

    Looking for CFD simulation help on this Aero experiment

    Hoping to get some help on a stability analysis of this setup...
  9. K

    B Preserving causality in the EPR experiment

    I have previously posted Preserving local realism in the EPR experiment . I have since given up on simulating local realism since I now understand it is impossible. However I have not given up on causality. Attached is code that simulates the EPR experiment and gives the same result as what...
  10. F

    I Thought experiment about wave functions

    Suppose we have a particle, let's say an electron, in a box of size D. And we add another one next to it at some distance L center to center. How do we solve for the wavefunctions of the electron. Can it be solved in normal QM or do we need QFT. Thanks.
  11. T

    Gyroscope Experiment Homework: Find Centre of Gravity & Nutation Effects

    Homework Statement Ok so in my lab we have been given a set-up as shown below Minus the horse shoe dector on the right hand side. During this set-up up we need to find the point where the balance point and centre of gravity are equal (as I understand) here is exactly what my script say...
  12. W

    I Spin confusion: Stern-Gerlach experiment

    I have some serious issues trying to understand the idea of the spin in the context of the Stern-Gerlach experiment and would appreciate some assistance! Assuming that a homogenous magnetic field ##B## in the "North-wards" ##z##-direction, assume that there is a magnetic dipole moment ##\mu##...
  13. M

    Thought experiment - water at the bottom of the sea

    So as we know at the bottom of the ocean we have water cooled to 0-4 degrees celsius which is very dense and also compressed due to the pressure. Imagine we lower a few kilometres long pipe to the bottom of the ocean (it's made of material that is strong enough to sustain pressure). It's closed...
  14. tinocasals

    Nuclear physics interesting experiments and activities

    Hi there, I'm looking for some interesting activities regarding nuclear physics in high school. I already have: - building a cloud chamber with dry ice or peltier modules - simulating radioactive decay with dice - simulating Rutherford's experiment hitting with glass marbles a hidden target...
  15. M

    B Unusual question about video experiment on YouTube

    Hello, I have found a YT video which shows some kind of experiment. You see a wooden toothpick suspended on a spider's web single thread and covered by a jar. Then a you see a man who holds a few plastic straws in his hand. He closes them to the toothpick and it slowly moves (which is seen if...
  16. S

    I Davison-Germer experiment - Bragg condition

    Hey, I'm trying to adapt the Bragg condition for the David-Germer experiment, so I can then use their experimental results to show that the measured wavelength is compatible to the wavelength theorized by De Broglie. However I'm having issue with the calculation, any help would be much...
  17. J

    Experiment to determine the time period of a pendulum

    Homework Statement Homework EquationsThe Attempt at a Solution Time period of a simple pendulum is given by 2π√(L/g) . By uniform mass distribution , I am assuming density of mass of bob to be constant . I don't understand how time period depends on the mass of the bob of a simple pendulum .
  18. Phillane

    I Delayed Choice / Quantum Eraser Experiment Question?

    Hello, Disclaimer: I have read other posts and understand it is important to reference ‘sources’ and that popular science articles / videos can be a source of annoyance. However, I am struggling to: A. Find an answer to my question, and/or B. Understand if my question is even valid. I hope...
  19. ElanaC

    B Double slit experiment question

    Hi, I have two questions concerning the double slit experiment in the scenario where we fire one photon at a time and it interacts with itself to create an interference pattern over time: - Does the photon actually interact with itself or with the photons fired before/after it? - What happens...
  20. D

    B What is the result of putting a detector on both slits in the 2 slit experiment?

    In the 2 slit experiment , what would be the result if we put a dedector on both slits? would we get an interference patern?
  21. A

    Setting Up an Experiment: Force vs. Displacement

    Homework Statement I'm trying to figure out the setup of an experiment I have to complete. The experiment calls for a rubber band to be secured by rods on the sides, and for a clothespin to be attached to the rubber band. I have to figure out how far back the clothespin needs to be pulled down...
  22. A

    A Decoherence in the double slit experiment

    I have two questions about the following type of scenario: We have a laser sending photons through the usual double slit apparatus giving us the usual interference pattern, except that now we introduce some physical matter (that are not photons) that the photons will interact with before going...
  23. Alfredo Tifi

    I Why isn't the Roemer type experiment a one way measure of c?

    I can't read the tons of posts and replies about one-way light speed in this forum. I was criticised once for sustaining light speed should be equal in both outward and return trips and Einstein's method of syncing clocks as the only reasonable one. Then I studied some scientific articles gently...
  24. Kostik

    I Does measurement destroy the interference pattern in the 2-slit experiment?

    I realize the 2-slit experiment is discussed at the beginning of countless QM books and YouTube videos. I have read the excellent exposition in the first chapter of Feynman & Hibbs, and appreciate that (using Feynman & Hibbs language): A. any determination of which among various alternative...
  25. K

    B Preserving local realism in the EPR experiment

    What is wrong with the idea that the spooky correlation in the EPR experiment is simply the result of the initial difference in rotation between the two polarizers in this experiment? So if you rotate one of the polarizers relative to the other polarizer, that initial act of rotation is what...
  26. ohwilleke

    I Anomaly aggregation and confirming old paper validity

    The Particle Data Group keeps a running, subject matter organized summary of the state of the art experimental results for the experimentally measured properties of hadrons and measurements of fundamental physical constants that is updated at least annually. Is there any comparable group that...
  27. T

    Magnetic field experiment confusion with error calculations

    Homework Statement I am having a issue with calulating my errors for this particular experiment the reason I will detail below. I have also print sceend in the section of my lab report to show the experimental setup etc. Lab Script So in the lab during the experiment the tesla meter...
  28. S

    Millikan Oil Drop Experiment: Determining Elementary Charge

    Homework Statement Calculate the charge on each oil drop and determine the elementary charge on an electron given the following: Voltage (Attached) d (Distance between two charged plates) = 0.10m m (Of the droplet) = 1.57x10^-15 kg g = 9.8 kgm/s^2 Homework Equations q = mg*d / ΔV The Attempt...
  29. G

    Need help with a thought experiment about a Faraday generator

    Hi, I arrived at a paradox today which I cannot explain myself. I was watching some physics videos on youtube and among them some were about lenz law and faraday disc workings. Now I know and understand the classical examples of why there is current generated when the magnet moves together with...
  30. J

    B Kim et al, 1999 experiment and causality

    Hi everyone! Sorry for my bad English! I read old posts in this forum, googled it and still can't figure out one thing: What other explanation could there be, other than a random event in the future determined if the photon behaved as a particle or wave in the first detector? Thanks a lot! I...
  31. B

    B Do Hot and Cold Air Balloons Fall at the Same Rate?

    Certainly a wooden ball and a stone fall with the same velocity. Would a balloon of cold air fall with the same velocity as a balloon of hot air? As a corollary, why does hot air rise over cold air? If you claim that cold air is denser, then the same argument fails when you compare a wooden...
  32. O

    I Concept underlying recent Serra-Lutz cold-to-hot experiment

    Hi, I'm trying to understand in a simple, non-mathematical way the basic concept underlying why a particular, very recent experiment turned out the way it did. The experiment, by Serra and Lutz entitled 'Reversing the thermodynamic arrow of time using quantum correlations', demonstrated an...
  33. MichPod

    I Modified double-slit experiment - two photons

    On the following link https://physics.stackexchange.com/questions/183961/modified-double-slit-experiment-two-electron-sources-instead-of-two-slits there is a discussion of the modification of double-slit experiments where two electrons sources are put in place of the slits. The conclusion is -...
  34. S

    Variables in a lab (controlled, independant and dependant)

    Hi! So it's new for me to do physics lab that way and my teacher is asking us to define the independant, dependant and controlled variables of every lab we're doing. I'm not quite sure what they refer to... For example, in a moment of inertia lab (see picture), I am asked this question. The...
  35. ohwilleke

    I Is there a fine structure constant running anomaly?

    Background The chart above, via Lubos Motl's blog which is standard in any textbook talking about supersymmetry, illustrates the running of the the inverse of the Standard Model (SM) and Minimal Supersymmetric Model (MSSM) coupling constants with energy scale for the electromagnetic force...
  36. MathematicalPhysicist

    A A technical question about the Joule-Thomson Experiment

    It's written in Kubo's textbook: I tried getting (2) from (1), but I get something different, I get: ##T\partial V / \partial T - V = TR/p+TRB+RT^2dB/dT-RT/p-RTB = RT^2dB/dT##, how to resolve this conundrum? Thanks.
  37. P

    B Geiger's Gold Foil Experiment: Exploring Atom Structure

    Hi, I'm confused a little about the gold foil experiment. I tried to put myself in Geiger's shoes, the author of the experiment. I'm firing alpha particles at a gold film, given that the plum pudding model is the pinnacle of human understanding of the atom, meaning I believe matter is made of...
  38. nomadreid

    I Exploring Malament-Hogarth Spacetime: Simplified Alice/Bob Experiment

    The article https://en.wikipedia.org/wiki/Malament%E2%80%93Hogarth_spacetime, the possibility of a space with a "worldline λ and an event p such that all events along λ are a finite interval in the past of p, but the proper time along λ is infinite" is discussed, and the suggestion is made that...
  39. Frenchies

    Help replicating Eratosthenes' experiment

    Hello, we are Maylis, Clara and Hélèna. We are students from a french high school in a class of «première scientific» (french equivalent of 11th grade) This year we have to be marked on Science more precisely on Physics. As a subjet we choose «the roundness of the earth: how Science is used to...
  40. K

    Why Does My E/M Experiment Graph Have an Unexpected Y-Intercept?

    So I am doing the charge to mass experiment and determining the relationship between: 1. accelerating voltage and radius formed by the electron beam 2. magnetic field strength and radius formed by electron beam Theoretically I should obtain an equation of the form: r = (1/B) *sqrt(2mV/e) where...
  41. J

    B Alain Aspect's experiment setting

    Hi everyone! Sorry for the bad english. I'm a psychologist from Brazil, so I don't know much of physics nor English. I'm having a hard time understanding his setting. In a very simple way, he made two entangled photons, each went to a polarization analyzer, that was set to random positions...
  42. S

    Fraunhofer diffraction experiment- neural density filters

    I'm currently carrying out an experiment with Fraunhofer diffraction. It involves shining a laser beam through neural density filters, a lens and a diffraction grating, to create a diffraction pattern which is then picked up with a CCD camera, to find the intensity of the maximal peaks. However...
  43. F

    I Confusion with the Photoelectric Experiment

    I've always struggled with circuits and never got a firm handle (hence the very basic questions...please bear with me). What I understand of Lenard's Experiment: Light hits the emitter plate and some electrons fly off. ...lol yeah that's about it. Here is one major confusion that I have: Not...
  44. T

    Millikan's experiment -- data confusion

    Homework Statement Hi guy I am having a real issue trying to find the fundamental charge from my data. So here is the background. Basically I carried out and experiment where we measured an oil droplet the was floating a specific voltage by taking the measurement of 12 oil droplets and...
  45. esha

    Penny on a card experiment.... explanation

    A card kept on a glass with a penny is jerked. The coin falls in the glass while the card moves away. why is that? My attempt at an explanation A force acts on the card which is greater than the static friction acting between the card and the coin. Hence the coin is able to overcome that...
  46. DaTario

    Fringes in a One Slit Experiment with a water tank

    Hello All, I would like to know why it´s so difficult to find information about the generation of fringes in a one slit interference experiment in a water tank. Best Regards, DaTario
  47. Z

    What errors did Rutherford encounter in his experiment

    Homework Statement What errors did Rutherford encounter in his experiment and how did he account for them. Homework Equations I believe there is an equation to find (b) but I don't know what it is.
  48. M

    Relativity: Initial velocity and e/m of Thomson's experiment

    Homework Statement In an experiment similar to Thomson’s, we use deflecting plates 5 cm in length with an electric field of 1.0×10^4 V/m. Without the magnetic field, we find an angular deflection of 30°, and with a magnetic field of 8×10^-4 T we find no deflection. What is the initial velocity...
  49. R

    I Two slit experiment w baseballs

    Would it be theoretically possible to perform a two slit experiment with, say, baseballs? How would such an experiment need be set up?
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