For those interested in the physics behind this this: http://en.wikipedia.org/wiki/Eddy_current

In conductors, electric currents are generated whenever there is a changing magnetic field. These currents generate their own magnetic field, which opposes the magnetic field which generates them. In this example, the magnet once dropped generates a current in the aluminum because as the magnet gets closer, the field gets stronger at the position of the aluminum. This generates a current, which creates its own magnetic field, acting on the magnet, and slowing it down.

Here's where it starts getting really interesting. The generated magnetic field will be notably weaker than the field of the dropped magnet, because the current is subject to electrical resistance. But what if we used a superconducting material, where there is zero electrical resistance, the two magnetic fields should equal eachother, right?

Check out this vid: http://videosift.com/video/The-Meissner-Effect-Awsome-physics

This is called the Meissner effect. This video shows an experiment of a strong magnet being put on top of a YBCO superconductor. All superconductors need to have their temperature dropped dramatically in order to to hit the superconducting threshhold known as a transition temperature. Typical transition temperatures are below 10 kelvin. YBCO is a unique material known as a high temperature superconductor, meaning that it can be cooled to its transition temperature with liquid nitrogen (about 70 kelvin).

Eugh, he said degrees kelvin.

@NetRunner, @gwiz665, especially @entr0py.

Everybody knows we should be using kelvins!!! You don't even need the °!
Why would you cut down trees to make tables when you have perfectly good Ks to measure temperature with?!?

>> ^visionep:
Zzzz...
He might as well be telling a bible story since there is no mention of the experiments or calculations that give rise to any of these theories.
It would be very interesting to me to see a footnote section to each of these stated theories which there are about a thousand. Anyone want to try? Go ahead and start with the first 10 to the -43rd second and explain why someone thinks the temperature was 10 to the 32nd degrees (C, F, Kelvin?).


It's either celsius or farenheit, because kelvin isn't measured in degrees. If anyone says "degrees kelvin", tell them they're wrong.

As for the video itself, i don't really like it. It sounds more or less correct for the standard model, but the explanations are really poor, he just throws stuff in.

You -do- realize that the difference between the systems of measurement would be less than -one- order of magnitude, right? When talking about an estimate that results in a number of that scale, the difference between Farenheit and Kelvin is far smaller than the margin of error, and Kelvin vs Centigrade is -utterly- meaningless. The difference between C and K is 273 degrees...which is not even a measurable deviation from a 32 digit number.
>> ^visionep:
I only ask which measurement system they are using because to me, and I assume to any discerning person who strives for knowledge, details are key.

Look, this is very different from a Bible story. The evidence exists, you just need to look further than a youtube video. If you need more information about the subject, try wikipedia. If you need more information, try a book meant for a layman. If you still need more information, try text books or physics classes. The information is accessible, but there probably isn't even a single experiment to point to, and it would probably take advanced physics knowledge to even understand some of them.

Also, keep in mind, this isn't a video that claims to be describing an absolute truth. It's a video describing the standard model. The standard model is a very successful model, but it isn't even a complete theory. As admitted in the video, it doesn't even explain gravity.

But I have to say, this series of videos are some of the best visualizations I've ever seen, and fills a gap by not treating the viewer like a complete idiot.

>> ^visionep:
Zzzz...
He might as well be telling a bible story since there is no mention of the experiments or calculations that give rise to any of these theories.
It would be very interesting to me to see a footnote section to each of these stated theories which there are about a thousand. Anyone want to try? Go ahead and start with the first 10 to the -43rd second and explain why someone thinks the temperature was 10 to the 32nd degrees (C, F, Kelvin?).

visionep:
Zzzz...
He might as well be telling a bible story since there is no mention of the experiments



I think you might be confusing popular science with academia. This is a nice little refresher and a different perspective on what you get in physics courses. Footnotes are usually in books. You know? Reading. The non-comic book kind.

[...]the temperature was 10 to the 32nd degrees (C, F, Kelvin?).



At that temperature level, does it really matter if it's degC, degF or K?


(Edited to fix quoting markup)

Zzzz...

He might as well be telling a bible story since there is no mention of the experiments or calculations that give rise to any of these theories.

It would be very interesting to me to see a footnote section to each of these stated theories which there are about a thousand. Anyone want to try? Go ahead and start with the first 10 to the -43rd second and explain why someone thinks the temperature was 10 to the 32nd degrees (C, F, Kelvin?).

Your video, Explaining temperature (kelvin) and laser cooling, has made it into the Top 15 New Videos listing. Congratulations on your achievement. For your contribution you have been awarded 1 Power Point.

Neeeeeeeeeeeeeeeerrrrrdddd

*does pushups*

In reply to this comment by demon_ix:
Geeky goodness
I remember referring to temperatures in Kelvin for a while. People couldn't understand why I thought a 290 degree day would be chilly...

Geeky goodness
I remember referring to temperatures in Kelvin for a while. People couldn't understand why I thought a 290 degree day would be chilly...

If god created space before time, there would be no energy. And without energy, the universe would be 0 Kelvins, thus negating any chance of life existing.

Oh, and any Christian who tries to explain (within the context of their belief) the facts that science has used to disprove the Bible is grasping for anything that can hold their worthless faith in hand. They are god's sycophants, and they don't deserve the marvels of science.

>> ^Crunchy:
While I dont believe in god, i have to defend the bible in this case.
You see, if a christian would see this video he could very easily discredit this fact.
As more and more "facts" are proven false in the bible christians (the more sneaky onces atleast) have agreed that those facts which are clearly proven false by modern day science or just common sence have abstract meanings like in this story for example 1 day is abstract because god hadn't created time and space yet, maybe space but not time!
If that fails, they can just say well... there were no video cameras back then! so how can u prove that it isint true!?
So what im trying to say, if ur trying to make an impact on somebody you should trap them untill they finally maybe possibly perhaps think for themselves.

Don't the names "Vince Kelvin" and "Johnny Wolf" both sound made up?

202 kelvin?

that's ~ -90 Fahrenheit or about 2 Kelvin