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.
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 .
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...
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...
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...
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...
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...
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...
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...
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...
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...
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...
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...
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...
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...
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...
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 -...
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...
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...
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.
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...
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...
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...
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...
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...
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...
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...
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...
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...
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
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.
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...
Homework Statement
I've linked my data table down below. My problem is the relative intensity column. From the table, the units of relative intensity are w/m/s. I'm assuming this is power/velocity, where velocity is the speed of light. However, nowhere in the lab manual did it mention the...
Hello there,
I have a question about the double-slit experiment and conscioussnes.
Excuse me if I don't formulate things right and might come over as a total fool for asking this (English is not my native language and i don't study physics).
I just saw this video: <Moderator's note: link...
Homework Statement
From a procedure standpoint, our experiment consisted of a laser pointer on a retort stand with a holder, shining through a piece of sheet with slit measurements (I believe it's acetate) and measuring the height of the maxima on a whiteboard. What could be improved with this...
From a procedure standpoint, our experiment consisted of a laser pointer on a retort stand with a holder, shining through a piece of sheet with slit measurements (I believe it's acetate) and measuring the height of the maxima on a whiteboard. What could be improved with this experiment?
I understand Young's Double Slit Experiment, which basically consists of pointing a laser through two slits and seeing the maxima with different brightness, caused by constructive and destructive interference respectively. Through the experiment, I know that increasing the distance between the...
I have a few basic questions about the double slit experiment and was hoping someone might be able to answer them.
1) How far apart from each other would have I have to make the slits so effectively no detection took place? E.g. is there a limit to how far the wave function can spread and a...
Here is a setup that only uses fixed detectors.
Will the ratio between the number of detections at D0 and the sum of the numbers detected on D1 and D2
be close to 1?
For this question instead of the coincidence counter, 3 simple counters are needed.
Also the detectors D1 and D2 need some lenses...
Homework Statement
Show that the electric field needed to make the rise time of the oil drop equal to the its field free time is
ε = (2mg)/q
Homework Equations
Newton's second law F = ma
The force of gravity FG = mg, where g = 9.8 ms-2
The force of buoyancy Fb = bv
The force of an electric...
Homework Statement
Basically there is a results table for the time taken for 20 oscillations. Three examples are 9.90, 11.16 and 12.68. I need to work out the time period to the correct number of significant figures.
Homework EquationsThe Attempt at a Solution
I divide by 20 to get the time...
How do we experimentally apply the operator ## \exp{\left(-i\phi\frac{ S_z}{\hbar}\right)}## on a quantum mechanical system? (Here ##S_z## is the spin angular momentum operator along the z-axis)
For example, on a beam of electrons?
I don't uderstand how, using special relativity theory (time dilatation and length contraction), one can explain why in the Michelson interferometer there is no delay between the two rays in the reference frame where the interferometer is moving. Consider the picture ##2.##
Setting...
In the photon version of the EPR experiment, how is the final polarization state of the photon detected?
I have read a number of high level descriptions of the EPR experiment, but I am having trouble with understanding the detection part.
Here is my understanding, please correct me where I am...
Ref: http://www.spaceref.com/news/viewpr.html?pid=51416
I would be very interested to see comments from knowledgeable people about this.
My impression is that this is one more example of a need to remain at least somewhat skeptical about theoretical models that have not yet been validated by...
Homework Statement
Hi,
I did an experiment where I launched a soccer ball into projectile motion with my hand and took a video the situation. I uploaded it into the Tracker software to analyze it. The tracker software gave me a x-t graph, a y-t graph, and a y-x graph. From the y-t graph...
I propose for your consideration the following version of this experiment:
We have a source, S that produce pairs of spin 1/2 entangled particles and two detectors, A and B that measure the spin of those particles. The detectors are oriented on the same direction, say X and they are fixed. As...