What did you learn today?

[whatthefunk]

I learned that if you press Alt + Tab you can flip through open applications very easily. I had no idea!!!!

[charles052]

When you have a child, you need to start shopping at garage sales A LOT MORE OFTEN. Retail, even when it's on sale, kills a budget.

[woodsmoke]

I learned that our preacher has even MORE of a sense of humour than I have thought!

As background the congregation has developed a "welcome" that is a very long list of pairings and that are read at the beginning of the service.

You are welcome here if:

You have skin that is red, yellow, black, white, or any other color.
You are welcome if you are married or not.
You are welcome if you believe all of the time, some of the time or none of the time.

There are eleven more sentences, but...

to the sense of humour that I learned about:

A couple that is ALWAYS at church early came in late...and right in the middle of the welcome.

The preacher glanced at them, and...without a single pause.....said:

You are welcome if you arrive on time or......fashionably late!

And the congregation was sliding out of their chairs from guffaw laughter!

We meet in the round, that is the reason for chairs not pews.

And, maybe this is one of those "you had to be there" things, but I am still laughing about it.

woodsmoke

[SecretCode]

"FRAGILE - Handle with care" signs are invisible to removals and shipping people.

[Snowhog]

That the Uncertainty principle is certainly a principle I won't understand fully anytime soon! (But the wiki page is really cool!)

[woodsmoke]

No, no, no my good friend Snowhog.

One can easily understand the basic premise of the Uncertainty Principle.

Basically, it is that at the sub-microscopic level, at least, since people have to use some kind of "indirect" measure of where something is, (position) and the speed/angular direction of where something is (momentum); one cannot measure with 100 percent accuracy BOTH of them at the same time.

And, by implication, one cannot "really" measure the simultaneous properties of "anything" with 100 percent accuracy.

An example would be that of measuring the speed of a bullet in a swimming pool. One can take a film of the bubble trail and measure the speed, and direction, over time, but the position is always changing.

Also, one can measure "where" a bullet hits a target, expecially if the bullseye has a "cross" in the middle, which is really the cartesian co-ordinates. But once the bullet begins to impinge on the paper one cannot determine it's speed with 100 percent accuracy.

Now, it would seem obvious that you know the speed and position of your cat walking across the room because you can "see" it, but actually, no, IN THE STRICTEST SENSE, because it takes an almost infinitisemal amount of time for the reflected light from the cat to reach your eye and the nerves to process the information to the brain, so, when you "think" you see the cat walking left it "infinitesimally minus .1 amount of time before the signal got to your eye, automagically reversed course and then re-reversed course and you won't see that until "infinitesimally plus .1 amount of time.

It really is as simple as that to "understand" but the math of the equations can be somewhat tedious and require other information to develop them.

This property of measurement of an object was then seized upon by the "Relativists" as "proof" that "everything is relative".

In other words, thee "relativists" extended a property of measurement to the philosophical postion that it "may" not be ok to murder a kid in our society; but other societies may be hunky dorey with that and so..... "everything is relative".

So..... see you CAN understand it...

woodsomethingsareNOTrelative(exceptthethreehorseth ievesthatwerelynchedinmyfamily)smoke

[capt-zero]

I thought the uncertainty principle meant: I'm not sure I understand...What were we talking about?

[kubicle]

So..... see you CAN understand it...

Unfortunately, it's a tad more complicated than that :P

The uncertainty principle has nothing to do with perception or the accuracy of our measuring equipment. The root cause is that at the fundamental level, subatomic (quantum) particles are affected by any kind of measuring, and some physical properties cannot be measured simultaneously (position and momentum are just one example of properties that cannot be known *simultaneously*)...it is, however possible to measure either position *or* momentum with 100% accuracy (just not both at the same time)...it's also possible to measure position and some other physical property simultaneously.

The uncertainty principle does have a small effect in macroscopic objects (even though it's a quantum mechanical trait), but the effect is negligible.

But once the bullet begins to impinge on the paper one cannot determine it's speed with 100 percent accuracy.

One could, if one would have the perfect measuring equipment for the job...it's possible to know the speed of an object with 100% accuracy (the uncertainty principle doesn't prevent that). In real life, it's extremely hard to measure things with 100% accuracy, but that's generally a limitation of our perception and/or measuring equipment, and not caused by the fundamental nature of matter (or the uncertainty principle)

[Qqmike]

+1 kubicle, exactly so ;-) No need for me to post mine now.

[HalationEffect]

Unfortunately, it's a tad more complicated than that :P

The root cause is that at the fundamental level, subatomic (quantum) particles are affected by any kind of measuring

According to an article I read recently, it's even worse than that:

Heisenberg proposed that the act of measurement itself was responsible for the indeterminacy: using a photon of sufficient energy to locate the particle would give it a kick, making its momentum unpredictable. However, later more rigorous derivations showed that the HUP—while still concerned with the measurement of physical quantities—didn't require a specific measurement to be performed. Instead, the HUP was a statement of the intrinsic limitation of any measurement that could be taken, without needing to do an experiment.

http://arstechnica.com/science/2012/...y-is-inherent/

[kubicle]

According to an article I read recently, it's even worse than that:
http://arstechnica.com/science/2012/...y-is-inherent/

Nice link. I was aware of the theory, but not that someone had found a way to test it. I'm not completely sold yet, but that's certainly plausible...given the nature of quantum mechanics where uncertainties and probalities rule...and common sense is useless .

[capt-zero]

I'm certainly uncertain of the explainations, but excuse me: I've got to get my cat out of the box.

[HalationEffect]

Nice link. I was aware of the theory, but not that someone had found a way to test it. I'm not completely sold yet, but that's certainly plausible...given the nature of quantum mechanics where uncertainties and probalities rule...and common sense is useless .

Hehe, it reminds me of a great line in an episode of Futurama: "All I know, is my gut says 'maybe'".

[woodsmoke]

Kubicle.

I don't really know what was going on with your reply to my post.

I purposely left out the "observer interfering with the observation" by the mere act of making the observation because I figured that it would muddy the water for somebody who thought they couldn't understand the basic idea of the uncertainty priciple.

Basically, the rest of your post says what mine said.

Halationeffect. I purposely did not mention that because it does, indeed, muddy the water and really is not part of the basic idea of the "uncertainty principle".

Kubicle mentioned "perfect equipment" which we will never have.

So, again, the basic idea, which anybody can understand, is that one cannot measure with one hundred percent accuracy both the position and velocity of a "particle" at the same time.

woodsmoke

[HalationEffect]

I find the easiest way to describe the Uncertainty Principle to those unfamiliar with it is to have them visualise a see-saw.

Using the common 'position-vs-velocity of a particle' example, imagine one end of the see-saw represents the accuracy of your knowledge of the particle's position, and the other end represents the accuracy of your knowledge of the particle's velocity.

If you increase the accuracy of one of the measurements (raising that end of the see-saw), the accuracy of the other measurement is automatically reduced (that end of the see-saw was lowered).