Double Slit Experiment

[Abstruce]

Here is a cool explanation of the double slit experiment.

 

http://www.whatthebleep.com/trailer/

 

My question is how can the act of observation effect the path of the electron? :hihi:

[Tormod]

Here is a cool explanation of the double slit experiment.

 

http://www.whatthebleep.com/trailer/

 

My question is how can the act of observation effect the path of the electron? :hihi:

 

IIRC the very act of observation means you are doing measurements on the particle, and as such it is affected by the measurement.

[Qfwfq]

Read 'observe' as 'interact with' and 'affect' as something like 'determine'.

[Abstruce]

Read 'observe' as 'interact with' and 'affect' as something like 'determine'.

 

Could it be that the particle has a problem holding its mass together?

 

Example:

 

A grain of sugar fired into water. The Grain travels as a particle until it dissolves and the energy of impact creates a wave effect in the water yet the particle of sugar has broke down.

[Qfwfq]

I'm not sure, ask Higgs. :hihi:

[sanctus]

Abstruce, the easiest way to understand what "measurement affects the system" is to know a bit about QM.

The easier example than the following example

You have already heard of electrons for example having a spin. Well, this spin can be directed on the x,y or z axis. Now imagine you have an electron with spin oriented along the x axis. You want to see what its spin is, but you don't know it so you try to measure it along the z-axis (for example with a magnetic field gradient) and so you will have an elctron which with probability 1/2 is along the z-axis in the positive direction and with a probability of 1/2 along the z-axis in the negative direction. Result:you wanted to measure the spin, you chose the wrong axis and imposed to the system to be either along the +z or the -z direction; while it used to be along the x-axis. Ergo your measure perturbed the system.

[Abstruce]

Ergo your measure perturbed the system.

 

Understood, what is so important that I am trying to get at is, by the electron traveling in the sea of energy it may disturb the energy around it thus creating a wave, yet still existing as a particle. So what is observed may be waves of energy strings that look as if they were electrons because the electron created a mirror effect when it disturbed the energy field.

[arkain101]

They make it seem in this movie that your spirit can make the world work how you want it. For example, if you could watch an electron, you could with your mind make it spin how you wanted. Because it is so small and easy for ones mind to manipulate..

 

But I have to agree that the setup of the observation has alot to do with the result produced.

 

I dont know enough about it to understand it quite exactly yet.

 

So if one was to blast light through the double slit, and get a view of a wave.. then walk over and look at the slit up close cause it to turn into double? as if it is intelligent..

[InfiniteNow]

Part of the issue is that depending on which measurement you choose to conduct, you will get different data... we collapse all other possibilities once we've observed one of them.

 

 

Explanation of the double-slit experiment:

 

 

In Young's original experiment, sunlight passes first through a single slit, and then through two thin vertical slits in otherwise solid barriers, and is then viewed on a rear screen.

 

When either slit is covered, a single peak is observed on the screen from the light passing through the other slit.

 

But when both slits are open, instead of the sum of these two singular peaks that would be expected if light were made of particles, a pattern of light and dark fringes is observed.

 

This pattern of fringes was best explained as the interference of the light waves as they recombined after passing through the slits, much as waves in water recombine to create peaks and swells. In the brighter spots, there is "constructive interference", where two "peaks" in the light wave coincide as they reach the screen. In the darker spots, "destructive interference" occurs where a peak and a trough occur together.

 

 

 

The thought experiment:

 

By the 1920s, various other experiments (such as the photoelectric effect) had demonstrated that light interacts with matter only in discrete, "quantum"-sized packets called photons.

 

If sunlight is replaced with a light source that is capable of producing just one photon at a time, and the screen is sensitive enough to detect a single photon, Young's experiment can, in theory, be performed one photon at a time -- with identical results.

 

If either slit is covered, the individual photons hitting the screen, over time, create a pattern with a single peak.

 

But if boths slits are left open, the pattern of photons hitting the screen, over time, again becomes a series of light and dark fringes.

 

This result seems to both confirm and contradict the wave theory. On the one hand, the interference pattern confirms that light still behaves much like a wave, even though we send it one particle at a time.

 

On the other hand, each time a photon with a certain energy is emitted, the screen detects a photon with the same energy. Since the photons are emitted one at a time, the photons are not interfering with each other -- so exactly what is the nature of the "interference"?

 

Modern quantum theory resolves these questions by postulating probability waves which describe the likelihood of finding the particle at a given location -- these waves interfere with each other just like ordinary waves do.

 

A refinement of this experiment consists in putting a detector at each of the two slits, to determine which slit the photon passes through on its way to the screen. But when the experiment is arranged in this way, the fringes disappear -- for reasons related to the collapse of the wavefunction.

 

[Jay-qu]

The easiest way that I understand the observation changing the path is using the Uncertainty Principle.

There is a electron, I want to know its velocity and position. To measure one of these you would shine a particular frequency of light on it and observe how it refects. To do this most accurately you would want a higher frequency because electrons are so small BUT the higher the frequency used the more energy in the photon and the more it will disrupt the path of the electron.

So the more accurately you try to measure the position the less accurately you know its velocity and vise versa.

[InfiniteNow]

The easiest way that I understand the observation changing the path is using the Uncertainty Principle.

That's an excellent point, too, Jay-qu. Observing literally pushes the observed item and changes it. Go Heisenberg!

[Abstruce]

That's an excellent point, too, Jay-qu. Observing literally pushes the observed item and changes it. Go Heisenberg!

 

So if I understand correctly what you are saying.

 

The power of thought doesn't effect the experiment.

 

It is only effected by the physical actions of the experimenter.

 

I find this whole matter doesn't exist, unless you are looking at it, hard to believe.

[Qfwfq]

The matter is discussed quite well in the Feynman lectures.

[Boerseun]

I have my own opinions regarding this, but if I post it, it'll make this thread automatically self-destruct and magically re-appear under "Strange Claims".

 

So, I won't post it.

[Qfwfq]

C'mon B, don't be afraid, start a new thread in Strange Claims!

 

Or even say it in the old Schrödinger's Cat thread in Philosophy of Science, it had enough strange claims in it anyway.

[Boerseun]

I have started a thread in Strange Claims quite a while ago regarding my views on light, but didn't get many takers.

 

Here's the gist:

 

Light exists in two-dimensional space, with zero time. As light, you don't experience time at all. Light emitted at the Big Bang will experience the Big Bang and the end of their travels (be it the End of the Universe, or striking your eyeball) at the same instant.

We intellectual, inquisitive bipeds, however, want to shoe-horn light into a three-dimensional form, behaving as we'd suspect three-dimensional things would behave. Therefore, we assign light the properties of both waves and particles. And we want to do this, because 3D stuff is the kinda stuff we're used to. We are 3D chauvinists.

 

Light is neither a particle, nor a wave. That's just what 2D things look like where it intersects with our 3D world. More advanced theories regarding even more dimensions than the three we have become accustomed to over the last few billion years, indicate that three isn't even the upper limit. And a being inhabiting 5D-space will speculate on why we humans act like a drongle under certain circumstances, and then act like a zweeble under other circumstances, whilst, in actual fact we're neither: The 5D-being is only describing our 3D interaction in his 5D universe in a way that can be understood in 5D space, when a drongle and a zweeble can't even be described in our 3D world.

 

A particle is a three-dimensional 'thing', which can't be described in 2D space. At best, only a 2D intersection of a 3D particle can be described in 2D space. But an intersection will not bring across the physical form of the 3D object, nor would a 2D-chauvinist being in 2D land easily understand what you're trying to illustrate.

 

A wave consists of forward motion, and an up-and-down oscillation along the path of transmission. But that doesn't describe light either, because a wave is dependent on a medium to be propagated in. And ether was blown out of the water.

 

There are lots of faults with either an exclusive 'wave' or 'particle' attribute, and this is being overcome by the uncomfortable marriage between the two states. I'm not claiming that I'm right, at all. All I'm saying is that it might be profitable to investigate the matter further, and hypothesize what exactly a 2 dimensional 'thing' would consists of, and how it would interact with a higher-dimensional world. If I'm right, then we can't really call it a wave or a particle, for these states are exclusively three-dimensional. We'll probably end up calling it, well, 'light'. And 'light' will act like 'light', seeing as the attributes of 3D oncepts like 'waves' and 'particles' aren't appliccable to it.

 

Yes - I know - pseudoscience, blah blah blah, I have moderated a few pseudoscientists posting outside of Strange Claims in my time as well. For this, I apologize profusely.

 

Cheers.

[sanctus]

Understood, what is so important that I am trying to get at is, by the electron traveling in the sea of energy it may disturb the energy around it thus creating a wave, yet still existing as a particle. So what is observed may be waves of energy strings that look as if they were electrons because the electron created a mirror effect when it disturbed the energy field.

 

There is a whole theory about that in solid state physicssuch electrons are called quasi-particles and they exite in their passage other electrons leaving a hole at a lower energy. The set of the origianl electron and the electron-hole pairs is called quasi-particle.

 

I find this whole matter doesn't exist, unless you are looking at it, hard to believe.[/Quote]

 

There is a huge discussion about that, it would deserve a thread in the philosophy of science forum. Just my view is if you don't observe it (also not indirectly, like if you are in a cave and never see the sun, you observe the sun anyway as temperature and so on stay livable) why should it exist?