But, they're LOOKING at it?

I'm watching Physics / 100 Greatest Discoveries with Bill Nye.

At 28:59 in this film, Bill Nye and Michu Kaku are looking at a Double slit experiment. If everyone remembers the theory, if an observer watches (measures) the effects of a photon going through the slits, what is seen is one point of light (one particle) on the background. This is because the act of observing supposedly collapses a wave into a particle. Like this:



But, that isn't what's happening! As you can see, Bill and Michu are looking at this experiment, and LOOK at what is showing up - a wave pattern! I don't get it?



Can somebody please explain?

Did the wave pattern show up when it was not being observed? I know it sounds weird how can you have a picture of it if it was not observed. I do not completely understand this experiment... The first time I saw was from this video.


But from what I am told this video has some huge flaws. I hope my post helps.

reply to post by jiggerj


I would like to know what happens if you were to move the medium the photons are hitting back towards the slit by very small increments.

The idea of wavelength and dual wave resonation come into mind, because light is a dual wave, correct? I had this thought a while ago about the possibility of the actual "photons" appearing at the intersection of the two waves. Perhaps, unless the medium it is hitting, or at least the part that is most visible to our eye, needs to be at the proper length from the slit to see this "intersection" where it is a singular particle.

I've read about this experiment in one of Michiu Kaku's books and from what I understood was that observing the experiment produced a differing result from that when it was not observed. Basically that when not observed all posibilities are played out and when observed only one is played out. Something of that nature at least anyway.

The place you have to observe is at the slit, where the particle/wave makes the decision to be one or the other, not downstream at the screen.

If you apply an observation at the slit - is the particle going through this slit or that one, that's when you collapse the wave into a definite particle.

Originally posted by Bedlam
The place you have to observe is at the slit, where the particle/wave makes the decision to be one or the other, not downstream at the screen.

If you apply an observation at the slit - is the particle going through this slit or that one, that's when you collapse the wave into a definite particle.

Right. But, from Bill Nye's position he is observing the entire experiment, before the slit and AFTER the slit.

Originally posted by jiggerj

Originally posted by Bedlam
The place you have to observe is at the slit, where the particle/wave makes the decision to be one or the other, not downstream at the screen.

If you apply an observation at the slit - is the particle going through this slit or that one, that's when you collapse the wave into a definite particle.

Right. But, from Bill Nye's position he is observing the entire experiment, before the slit and AFTER the slit.

You have to "observe" with an instrument that can detect the particle at the slit as a particle. Looking at it won't do.

Originally posted by jiggerj
if an observer watches (measures) the effects of a photon going through the slits,

Not quite.
The "observation" that works this way is where an instrument is detecting which specific one (of the two) the photon is actually going through at that moment.

The question: Is this photon going through the left slit, or the right slit (or both)?

The human eye cant do that.

Originally posted by Bedlam

Originally posted by jiggerj

Originally posted by Bedlam
The place you have to observe is at the slit, where the particle/wave makes the decision to be one or the other, not downstream at the screen.

If you apply an observation at the slit - is the particle going through this slit or that one, that's when you collapse the wave into a definite particle.

Right. But, from Bill Nye's position he is observing the entire experiment, before the slit and AFTER the slit.

You have to "observe" with an instrument that can detect the particle at the slit as a particle. Looking at it won't do.

Indeed and it is this instrument that is causing the collapse of the wave pattern due to it entangling the particle with an electromagnetic wave. Electrons (the particles being observed) don't give off any energy to begin with and due to this energy must be added to them to detect them indirectly (without causing an impact or stopping them in some way).This energy forces the electron(s) to release photons so an instrument can detect it.

It is this energy being added that is forcing the electron(s) into our locality otherwise it would normally be non-localized.

So basically, the experiment has NOTHING TO DO WITH HUMAN OR OTHER CONSCIOUS OBSERVERS!

This is what annoys me about the metaphysical community as this single misunderstanding has caused them to think their beliefs are somehow rooted in reality... it isn't.

Quantum theory is easy enough to understand so long as you understand both the double-slit experiment and quantum entanglement to their FULL EXTENT.

reply to post by Elzon1


Once you know what slit it went through, you know which universe you've ended up in. Simple.

reply to post by Elzon1


ZOINKS! You put it in a way I can relay it when I need to. Makes it very simple to understand, despite having understood it for a long time. Amazing how the right words can do that.. lol, not that I could find an eloquent way to put it in an understandable manner.

It's insane how many people think that it's the conscious act of observing that is affecting the outcome, not the fact that we have to interfere with the particles being observed in order to observe them..

And yet the what ifs concerning quantum mechanics are plenty... what the 'bleep' do we know, indeed (NO do not quote me as endorsing that series, argh!! boohiss*)

The photons from the screen have to travel to the observer's eyes as well, so they can picture it in their brains. This adds another step in their journey - they are not only particaling or waving through the slit and to the screen, they are also dividing up into very small packets and emiting an unimaginable amount of photons in every direction which has line-of-sight.

reply to post by Aleister


That doesn't matter for the double slit experiment, though. To get that one to collapse, you have to spot the slit it went through. Downstream, your eyes can't tell. So it doesn't matter.

Originally posted by Elzon1

So basically, the experiment has NOTHING TO DO WITH HUMAN OR OTHER CONSCIOUS OBSERVERS!

This is what annoys me about the metaphysical community as this single misunderstanding has caused them to think their beliefs are somehow rooted in reality... it isn't.

Quantum theory is easy enough to understand so long as you understand both the double-slit experiment and quantum entanglement to their FULL EXTENT.

That would be comfortable yes, but does not agree with the data from experiments SPECIFICALLY investigating that:
For example. www.deanradin.com...

Originally posted by asciikewl
That would be comfortable yes, but does not agree with the data from experiments SPECIFICALLY investigating that:
For example. www.deanradin.com...

Interesting paper, from an UNpeer reviewed journal, by the "Institute of Noetic Sciences", but hardly constitutes proof.
Fundamentally, they've really been looking at random noise.
Take for example, this chart of attention vs. results...

I defy anyone to show me any relationship at all between the attention and the randomly moving result line.

And whats with the lag/lead??? They pulled that one out of their butt! Supposedly the results were so bad that they decided that the random noise might produce a better result if one supposes the effect happens at a time when the cause isnt happening.

But mostly, its what I'd expect from Dean Radin, the man that "proved" psi without actually finding anyone that can do psi. Rather, just mining statistical data looking for some kind / any kind of relationship.

Originally posted by Elzon1

So basically, the experiment has NOTHING TO DO WITH HUMAN OR OTHER CONSCIOUS OBSERVERS!

That's good to know, but I've seen examples in documentaries where a human was watching the experiment and causing changes. I've been searching for one of them, but of course I can't find one of them. The experiment even went so far as to show a man opening and closing his eyes and causing (what the documentary described) as the photons actually going in reverse and starting all over again. I'll keep looking.

Originally posted by alfa1

Originally posted by jiggerj
if an observer watches (measures) the effects of a photon going through the slits,

Not quite.
The "observation" that works this way is where an instrument is detecting which specific one (of the two) the photon is actually going through at that moment.

The question: Is this photon going through the left slit, or the right slit (or both)?

The human eye cant do that.

Alfa1 and bedlam are right.
This is one of those cases where "observe" has different meanings to a scientist and to a layperson. Even the term "observer effect" has a disambiguation page on wikipedia.

I made a thread on a different aspect of the observer effect (physics) related to temperature since people seem to get intellectually flustered when discussing quantum mechanics, and I thought temperature might be simpler to understand, but it's a similar effect:

In science, the term observer effect refers to changes that the act of observation will make on a phenomenon being observed. This is often the result of instruments that, by necessity, alter the state of what they measure in some manner.

Note the reference to instruments, and this doesn't mean to "look at" as when a layperson says "observe".

In thermodynamics, a standard mercury-in-glass thermometer must absorb or give up some thermal energy to record a temperature, and therefore changes the temperature of the body which it is measuring.

And that is more or less the topic of my thread explaining the observer effect in thermodynamic terms:

The "observer effect": Is it proof the system is "aware it's being observed?"

Originally posted by Arbitrageur

In science, the term observer effect refers to changes that the act of observation will make on a phenomenon being observed. This is often the result of instruments that, by necessity, alter the state of what they measure in some manner.

Note the reference to instruments, and this doesn't mean to "look at" as when a layperson says "observe".

Hi Arb, you seem to grasp QM a LOT more than I do, so can you tell me why the Back Sensor isn't included as a measuring device in the double slit experiment? When the photon waves and/or particles hit that backboard, isn't this a form of measuring? We are using the backboard (or whatever it's called) to see how the photons are reacting. Isn't this measuring? Am I making ANY sense at all?

Originally posted by jiggerj
I'm watching Physics / 100 Greatest Discoveries with Bill Nye.

At 28:59 in this film, Bill Nye and Michu Kaku are looking at a Double slit experiment. If everyone remembers the theory, if an observer watches (measures) the effects of a photon going through the slits, what is seen is one point of light (one particle) on the background. This is because the act of observing supposedly collapses a wave into a particle. Like this:

But, that isn't what's happening! As you can see, Bill and Michu are looking at this experiment, and LOOK at what is showing up - a wave pattern! I don't get it?

Can somebody please explain?

edit on 1/7/2013 by jiggerj because: (no reason given)

They must be looking at it after the event was recorded absent human thought interference.