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.
I'm an engineer who has an amateur interest in physics. I have been reading about Einsteins light clock experiment. I understand the principal that when a light clock on a train etc is moving relative to a standing still observer then the light must travel a longer distance per tick. given that...
Hi to all who might respond,
Consider the 'peculiar' double-slit setup below.
There is a double-slit configuration such that the two slits are never open at the same time. That is: whenever the top slit is open for a certain interval, Ts, the bottom slit is closed for the same interval and vice...
I'm new to the concept of diamagnetism, but it seems very fascinating, and I'd like to try a simple experiment. Say I wanted to repel a small piece of lead (or copper, both are readily available to me) about 3.5 grams, how strong of a magnet would I need? Could I just use small neodymium magnets...
Let's say you take a beam of particles and pass it through a Stern Gerlach apparatus and you select one of the outgoing beams, therefore collapsing the wavefunction to certain values of orbital angular momentum and spin angular momentum.
If you performed the Zeeman experiment on that beam, I'm...
I find this question rather difficult!
Q1. I take Fig 1-11 to be the laboratory frame and ##v## to be the velocity of the ether wind. Since Lorentz length contraction occurs only horizontally, the right mirror should be further to the right horizontally in the ether frame. This makes the angle...
A thought experiment about the speed of light. Say I build a 600,000 km long tube around the circumference of the Earth at the Equator. The tube's inner diameter is constant at 54.4505 mm. A snooker ball is perfectly manufactured to its lowest tolerance by a special new machine. Each one is...
It seems that with the 2016 LIGO and VIRGO confirmation of the gravitational chirp that we have also experimental confirmation that the speed is indeed the speed of light. True?
https://en.wikipedia.org/wiki/First_observation_of_gravitational_waves#Direct_observation
The ATLAS experiment has seen a bump that could be a new particle at a mass of 3.0 TeV/c^2 with a local significance of more than three sigma, and a global significance of a bit more than two sigma in Run-2 data looking at decays of qqbb states to a W or Z boson and a Higgs boson.
It is...
https://www.sciencedaily.com/releases/2015/02/150209083011.htm
All I got out of the experiment is that the future measurements makes the measurements in the past more accurate. The future does not affect the past. Please correct my errors if any.
Okay, let me prelude this by saying I only have an -EXTREMELY- limited understanding of classical physics, and zero knowledge of quantum mechanics. This is really just my asking a few questions in regards to an idea I had for an experiment, and what would be a good and accurate way to...
is there a reason that Deep Underground Neutrino Experiment which uses 70, 000 tons of liquid Argon doesn't also do double duty work as a proton decay experiment?
Argon has plenty of protons and 70, 0000 tons is a lot of material to work with
it costs several billion dollars so why not use...
In my experimental setup I have a purpose built small aluminium tube that has a black layer on the inside to mimic a blackbody.
The tube is heated so the inside emits as a blackbody. A separate temperature sensor attached to the tube gives the temperature of the tube.
I have a thermopile...
Hi all!
I have a cyclette with 8 resistance levels set magnetically using a knob (a magnet is moved near the rotating disk thereby increasing its rotating resistance). The distance from the pedal to the center is 0.165 m. At resistance level 4, if I put a weight greater than or equal to 0.750...
My book gives the following graph for current vs accelerating potential for Franck and Hertz experiment (used to prove existence of discrete energy levels in atoms) using Mercury vapours in the tube:
The book then writes:
"Actually, atoms have more than one excitation potential and also an...
Suppose you wanted a thought experiment about a variation on the vacuum (i.e., the spatial slice of spacetime) in which the quantum effects were absent or negligible, and the vacuum energy was zero . What would you call it? You can't call it the vacuum, because this Newtonian version of the...
I heard many people saying that the delayed choice experiment means that future events can affect the past. I doubt it as I believe that the wavefunction of the particle collapses as soon as a measurement is made. It does not matter where the detector is placed. As long as there is a detector...
I have a thought experiment that i need a answer to. In my experiment, I am in a bathroom with a mirror along one wall. I also have a laser that emits a single file line of photons. The laser is attached to the ceiling and emits a line of photons parallel to the mirror. What property of light...
In a 'one photon at a time' double slit experiment, does the interference pattern still emerges if the time delay between individual photon emissions is increased to minutes or even hours?
Homework Statement
We were given two methods to look into Newton's 2nd Law and evaluate them by looking at where sources of error may have come from. They both involved accelerating a car across a table. A plastic track was used to guide the car along a straight path to make sure it went...
I know this won't work, I'm having trouble explaining why to someone who thinks it will.
Make a ring around a planet. Give it low walls. Fire countless pellets at hypersonic speeds around the inside of the ring. The pellets are moving at super-orbital speed, pushing the ring outward, making it...
I attach an image of something I am experimenting with.
The picture itself (and added text) should be self-explanatory.
1) Which way should my windings (clockwise or counter-clockwise) go around P1; P2; P3 & P4 for maximum voltage (V) ?
[ 1 Ø ]
[ 1 x single enamelled copper conductor ]
[...
Relativity, Resnick
Here, for calculating t2 , w.r.t. ether frame, light is moving along the triangular path as shown in Fig. 1.7 with speed c.
w.r.t. interferometer frame, light is moving along the straight path with speed c##\hat y## - v ##\hat x## while going up and with speed -c##\hat y##...
Hi
I am running the electroscope experiment in vacuum. This is shown in (a) in the uploaded figure . Once the aluminum leafs are charged the chamber is pump down (b). As soon the pressure decrease low enough (around relative pressure of 30 inHg) the leafs collapse to each other abruptly.
Here...
Hi, Physics Forum!
I've been wondering what would happen in the following thought experiment. I am not physicist and may have made some incorrect assumptions. Please explain if any of these assumptions are wrong.
What would happen if you threw a piece of (very long and strong) rope into a...
Dear All,
I have a couple questions on the double slit experiment I hope you can help shed some light (or photons) on. =)
Arrival Timing of Photons
In a normal double-slit experiment like the above setup, do photons always arrive at the detector at a constant speed (basically, speed of light)...
Came across a pair of websites claiming to be DIY Quantum Entanglement Experiment. Problem is, I don't know how realistic it is. Essentially, is this real, or am I being taken for a fool?
Part 1...
Homework Statement
Lorentz suggested that L parallel shortens the amount:
And inserting it back cancels the time difference:
$$\frac{2L/C}{\sqrt{1-u^2/c^2}}>\frac{2L/C}{1-u^2/c^2}~\rightarrow~t_1+t_2<2t_3$$
Logic says i have to increase L in order to increase t1+t2 so it will equal 2t3...
Light bulbs and cathode ray tubes are structurally similar in some respects. For example, both contain a filament -- in the light bulb, the filament heats up to produce light, while in a cathode ray tube, the filament emits electrons, which are then steered into a target (in a CRT TV, the...
Hello everyone,
The questions I am about to ask have probably been explained already, but even after everything I've read I still cannot understand how this experiment would play out and how to answer these questions. So without further ado here is the experiment:
Imagine you have person A...
Just recently I came up with a new idea to measure one way speed of light and/or synchronize distant clocks:
Let’s have two light sources at points A and B separated by distance d and sending constantly (perpendicular to AB) signals to clocks at A’ and B’
Let’s have an opaque rod of the length...
Dear All,
I have a question on the double slit experiment. From the references I've read so far, they are focusing on the results of the detector AFTER the 2 slits.
Let's say when photons are fired, how many % actually pass through the slits and get detected at the end? Would some (and how...
So for my curriculum I have to do a physics experiment and write a 2000 word essay on it. For my experiment, I'm planning to wrap a string with a ball attached to it n number of times around a pole and measure the time taken for it to unwind by changing variables such as the radius of the pole...
Has anyone ever thought that the wave pattern on the screen is not because the particle is a wave. There is no reason that the wave appearance could not be due to a photon being distributed in this fashion and still be a particle while both slits are open. You have a different distribution with...
Homework Statement
So, my physics professor has been behind all semester long and basically taught the entire light wave and optics chapters in a single day and explained absolutely nothing, hence massive confusion on the following problem:[In a double-slit experiment, the slit separation is...
Homework Statement
I have a rotating platform that spins as a mass attached to a wheel rotates the larger platform. The mass accelerates to the ground which spins the platform essentially. I am trying to calculate the moment of inertia of another mass which will be attached to the rotating...
Hi, my answer is about the double slit experiment: the interference is observable with the water waves, them are particle in movment, but when we observe it with the electrons, what is the medium for those waves? Are the particles made of matter between the gun and the slits? Or is it something...
I have a question concerning the nature of Ms. Wu's experiment confirming parity violation. I'm very familiar with this experiment and its outcomes, but the setup of the experiment itself, alludes me.
Wu found that the electron's emitted from the Cobalt-60 atom always went in the direction...
I've always been curious about how rigorous are the Casimir force measurements carried out, because a couple of years ago I read some news about people inventing perpetual motion machine which turned out to be draining power from environmental EM noises, say, radio station, wifi, 3G/4G that keep...
Exciting to see CERN coming back to experiments. Of interest is the n_TOF instruments to study the estimated age of the universe through neutron-induced reactions of the 'Rhenium-Osmium'cosmo-chronometer. Anyone have a more detail explanation of how this device works? The rhenium-osmium isotopic...
Hello! Does anyone here have raw data from a delayed choice quantum eraser experiment that you wouldn't mind sharing? Ideally, data from all the detectors, not just coincidence counts that the analysis usually focuses on? Or, are you aware of any data repository where data from quantum physics...
Usually one would expect through \sigma=ne^2 \tao/m and DOS~1/m to argue that \sigma ~ DOS around Fermi surface. This seems to be a quite fundamental argument and should be expected to hold most of the time. For a quality check, does anybody have experience on how often LDA gives consistent DOS...
All these videos and articles about the Double Slit Experiment say that if we "look" where the single photons go, they act like particles and if we don't "look" they act like waves, creating the interference pattern...
BUT
What does it mean to "look"? We're not using our eyes or any camera...
Suppose we have two charged particles on the laboratory and two observers A and B.
##A## is inside one of the charges (never mind how)
##B## is sitting at the laboratory
In the lab reference frame we accelerate the particles. According to ##A## there will be only electric attraction or...
Homework Statement
A car driving at a speed of 60km/h at a horizontal road.
The car accelerates to 65km/h, and then the engine gets deactivated. The speed then decreases to 55km/h in a time of 7,2 seconds.
The mass of the car is 1450 kg(the car, passenger etc...)
Homework Equations
What is the...
I just started reading Stern Gerlach Experiment and this thought crossed my mind. Totally a hypothetical question. If I pass an electron and positron through separate SG apparatuses, I will know in which spin state each particle has collapsed. But afterwords I let electron-positron pair...
Hello fellow physics friends (alliteration: always a strong opener). I am writing today because I find myself struggling to complete something which ostensibly doesn't seem that difficult to the average physics undergrad working in a lab. However, electronics and circuits are definitely a...
Homework Statement
problem no.3
Homework Equations
<ΨㅣΩㅣΨ>
The Attempt at a Solution
I used <ΨㅣΩㅣΨ> and but I don't find solution
lΨ(t)>=?
I need help...