YouTube Classics: Watch & Learn Kids

[Ivan Seeking]

A 361 mph school bus [allegedly]

https://www.youtube.com/watch?v=KQ2iNOmPI-0

 

[Borek]

I was shown this guy on some other forum:



As usual, I started to browse other videos from the same page, and I found this guy - he is pretty funny, especially if you have ever heard these cars (I am afraid most of you have even never seen them on pictures, but let's try):

ED5UT-t9WJ0[/youtube] Don't ask me why these videos have Polish titles. Not my fault.

 

[Willowz]

If anybody can tell me the clip used in this music video, I'd really really appreciate it.

mig-I2QGq6Q[/youtube]

 

[BobG]

What do you get when you fall in love?


https://www.youtube.com/watch?v=mhxK2IOywVE

 

[rootX]

 

[OmCheeto]

I am a nerd.

https://www.youtube.com/watch?v=iABmUEH5s0k

 

[Ivan Seeking]

Fun with supersaturated solutions. This was my favorite demo when a Freshman in college. I just had to buy some sodium acetate and have my own for guests. Our microwave smelled like an aspirin factory forevermore. In fact, as a result, to this day I am hypersensitive to the smell of acetate.

https://www.youtube.com/watch?v=kZNQLAGE1U0

 

[jobyts]

For all the animal lovers:


https://www.youtube.com/watch?v=HNMq8XS4LhE

 

[Ivan Seeking]

That is just wrong!

 

[ArcanaNoir]

Why does the magnet in the super magnet man video neither repel nor attract the aluminum but instead do the "slow-mo" thing? Is the aluminum magnetically attractive or not?

 

[OmCheeto]

Why does the magnet in the super magnet man video neither repel nor attract the aluminum but instead do the "slow-mo" thing? Is the aluminum magnetically attractive or not?

It's something that is really hard to understand.

Until you see things, the way they really are.

My own suspicion is that the Universe is not only queerer than we suppose, but queerer than we can suppose.

sorry for the cross thread...

 

[rootX]

That is just wrong!

I don't even want to comment on that video

 

[Borek]

That is just wrong!

But shot perfectly

 

[Jimmy Snyder]

The special effects were impressive. I actually thought they were girls.

 

[ArcanaNoir]

It's something that is really hard to understand.

Until you see things, the way they really are.

Oh come on, I know a thing or two, just try me. I'd really like to know.

 

[OmCheeto]

Oh come on, I know a thing or two, just try me. I'd really like to know.

Aluminum is non-magnetic, but by passing electricity through it, you will generate a magnetic field. The change in magnetic flux as the magnet approaches the aluminum generates a current flow in the aluminum, which generates a magnetic field which repels the magnet. But the aluminum has electrical resistance, so the current drops, and it's field collapses, as the magnet comes gently to rest.

 

[jobyts]

That is just wrong!

Come on, think those poor little furry animals as humans; you would enjoy it :)

 

[Borg]

Here's something you don't see every day.

https://www.youtube.com/watch?v=bUGjUCHSKLM

 

[collinsmark]

Oh come on, I know a thing or two, just try me. I'd really like to know.

'Like OmCheeto said.

Putting it another way, aluminum is a paramagnetic material with a relative permeability (μ_r) of only 1.000022. Empty space has a μ_r of 1.0000000. Which means aluminum is not very magnetic at all. (For comparison, steel has a μ_r of around 100.)

But aluminum is a fairly good conductor. And any time you wave a magnet around a conductor you get emf (a.k.a. voltage), and in a closed circuit that means currents, even if the currents are circulating within the aluminum sheet itself. Any time you get current, you get magnetic fields (whether the conductor is magnetic or not).

This induced current always opposes the *change* in magnetic field. So when the magnet falls on the aluminum sheet, the magnetic field is changing because the magnet is moving. The induced current in the aluminum opposes this changing magnetic field, producing its own magnetic field which in turn slows the magnet.

This phenomenon shown in the video is more common than you might think. It is the principle behind the induction motor. This is what household fans use, as well as laundry dryers (among may other things). Using a number of stationary coils connected to a 3-phase AC source (actually, any number of phases is possible, it doesn't need to be 3-phase), a rotating magnetic field is created. Then what is essentially an aluminum hamster wheel naturally spins around inside trying to keep up with the spinning magnetic field (no brushes or any external electrical connections whatsoever are needed on the hamster wheel). This is similar to how the aluminum plate moved with the magnet when the magnet was moved back and forth.

 

[Ivan Seeking]

But shot perfectly

I remember hearing about this guy. Eventually he escaped from prison and he's been on the lam ever since.

 

[OmCheeto]

'Like OmCheeto said.

Putting it another way, aluminum is a paramagnetic material with a relative permeability (μ_r) of only 1.000022. Empty space has a μ_r of 1.0000000. Which means aluminum is not very magnetic at all. (For comparison, steel has a μ_r of around 100.)

But aluminum is a fairly good conductor. And any time you wave a magnet around a conductor you get emf (a.k.a. voltage), and in a closed circuit that means currents, even if the currents are circulating within the aluminum sheet itself. Any time you get current, you get magnetic fields (whether the conductor is magnetic or not).

This induced current always opposes the *change* in magnetic field. So when the magnet falls on the aluminum sheet, the magnetic field is changing because the magnet is moving. The induced current in the aluminum opposes this changing magnetic field, producing its own magnetic field which in turn slows the magnet.

This phenomenon shown in the video is more common than you might think. It is the principle behind the induction motor. This is what household fans use, as well as laundry dryers (among may other things). Using a number of stationary coils connected to a 3-phase AC source (actually, any number of phases is possible, it doesn't need to be 3-phase), a rotating magnetic field is created. Then what is essentially an aluminum hamster wheel naturally spins around inside trying to keep up with the spinning magnetic field (no brushes or any external electrical connections whatsoever are needed on the hamster wheel). This is similar to how the aluminum plate moved with the magnet when the magnet was moved back and forth.

Where's the report button! We are so way off topic.

If Arcana want's to know what's really going on, she needs to start her own thread.

I tried to keep my post short and simple, so as not to attract the neutrino (what if?) hoards.

Actually, I played with my little 1 gram super magnets after I saw the video, and recreated the experiment. It was much less impressive, but confirmed that the video was legit.

Now I want to see a 5 lb super magnet dropped on a sheet of aluminum foil.

 

[Ivan Seeking]

Back when I worked on MRI units, this was one of our favorites.

https://www.youtube.com/watch?v=fxC-AEC0ROk

1.5 Tesla - better!

https://www.youtube.com/watch?v=liDjr439-fY

 

[OmCheeto]

Back when I worked on MRI units, this was one of our favorites.

https://www.youtube.com/watch?v=fxC-AEC0ROk

1.5 Tesla - better!

https://www.youtube.com/watch?v=liDjr439-fY

Well, I don't have several million dollars to spend on a googleplex tesla magnetic flux MRI machine, so I will settle for...

Ah! Now I think I know why we have one of the most powerful MRI's on the planet at work.

"Research only"

It will suck the iron out of your blood, just like Dr. Magneto...

X-Men!

 

[Borg]

I remember hearing about this guy. Eventually he escaped from prison and he's been on the lam ever since.

:rofl:

 

[Ivan Seeking]

Well, I don't have several million dollars to spend on a googleplex tesla magnetic flux MRI machine, so I will settle for...

Ah! Now I think I know why we have one of the most powerful MRI's on the planet at work.

"Research only"

It will suck the iron out of your blood, just like Dr. Magneto...

X-Men!

Actually, you guys probably have two or three diagnostic MRI units. I would bet dollars to donuts that you could track down an engineer for those units and get a demo.

 

[ArcanaNoir]

Aluminum is non-magnetic, but by passing electricity through it, you will generate a magnetic field. The change in magnetic flux as the magnet approaches the aluminum generates a current flow in the aluminum, which generates a magnetic field which repels the magnet. But the aluminum has electrical resistance, so the current drops, and it's field collapses, as the magnet comes gently to rest.

This explanation is quite satisfactory, thank you.

Where's the report button! We are so way off topic.

If Arcana want's to know what's really going on, she needs to start her own thread.

It was a tiny little question relevant to the video posted. What's the problem? I wasn't asking for a dissertation, just a basic explanation. I quite like the answer you posted. Why you so whiny? :P

 

[OmCheeto]

Actually, you guys probably have two or three diagnostic MRI units. I would bet dollars to donuts that you could track down an engineer for those units and get a demo.

Well, I did know the guy that was the super conductor tech for our 3 machines, but he was, how do you say, outsourced? Anyways, I looked it up, and our biggest machine is 15 Tesla. (Which means absolutely nothing to me, other than I learned today that it takes 17 Tesla to levitate a little frog)

https://www.youtube.com/watch?v=2VlWonYfN3A

Do you think they could float a pea for me?

 

[KrisOhn]

This is amazing

 

[OmCheeto]

This explanation is quite satisfactory, thank you.



It was a tiny little question relevant to the video posted. What's the problem? I wasn't asking for a dissertation, just a basic explanation. I quite like the answer you posted. Why you so whiny? :P

Sorry for being whiny. I guess I was just jealous of collinsmark much more intelligent explanation.

But anyways, I could watch these videos all day long.

https://www.youtube.com/watch?v=E97CYWlALEs

https://www.youtube.com/watch?v=H31K9qcmeMU

I don't think super magnets were as readily available when I went through college (30 years ago) as they are now.

Oh! Here's one that illustrates what collinsmark was describing:

...

This phenomenon shown in the video is more common than you might think. It is the principle behind the induction motor.

...

https://www.youtube.com/watch?v=cIf9iPskgJs

 

[QuarkCharmer]

https://www.youtube.com/watch?v=nGOfZ5iRtfA

 

[BobG]

Mondays are hell!


https://www.youtube.com/watch?v=JVRjLErrAFQ

If we clean this up really quick, maybe the boss will never find out about it?

 

[BobG]

Something like that never would have happened to this guy!


https://www.youtube.com/watch?v=CuGBpwnWW2I

 

[Borek]

Rather hermetic, but for those ever involved in demoscene - fantastic!

 

[fuzzyfelt]

Rather hermetic, but for those ever involved in demoscene - fantastic!

I like that!

 

[Borek]

I like that!

See http://countercomplex.blogspot.com/2011/10/algorithmic-symphonies-from-one-line-of.html for more.