Greetings fellow nerds.
Quick question.
[dialogue on screen]
Most of you will answer C and you wouldn't be wrong,
after all in everyday life you'd notice nothing unusual about water and magnetism.
But interestingly enough the correct answer is B)
water is actually slightly repelled by a magnet.
This anti-magnetic property is called diamagnetism.
However the effect is extremely weak,
that's why most people don't know it's there.
To see it we need to build an extremely sensitive detector.
Luckily, this is brutally simple.
Just get a basin of water and then put into it a Styrofoam block.
It's going to move around a lot but this is actually a good thing.
The Styrofoam floats and because it's so light even the smallest force will push it around.
So try and build this away from drafts and moving air
and be careful that your own breathing doesn't disrupt it.
The water helps to dampen any stray motion.
Now get a test tube and fill it with water and push it into the center of the Styrofoam.
This is the water we're actually going to measure, not the water in the basin.
Now steady it and when it's still,
get a strong neodymium magnet
and hold it as close as possible to the tube without touching it.
Whoops, I hit it there,
let me steady it...
Ok let me try it again.
Slowly, but surely, it's moving away from the magnet.
It's an extremely weak effect, but it's happening.
A perceptive viewer will also ask about the glass,
and yes the glass is also diamagnetic and also contributes to the repulsive effect.
Now it doesn't matter the orientation of magnet,
there is no north or south in a diamagnetic material,
it will always be repelled by the magnet.
Now this video was time-lapsed, it actually moves a lot slower than this,
I’ll show you the actual speed at the end of this video.
Moving on, I’m going to show this special material called pyrolytic carbon.
Sometimes called pyrolytic graphite,
it's made by heating a hydrocarbon to decomposition temperature without oxygen.
Pyrolytic carbon is much more diamagnetic than water, and it's pushed around quite easily.
In fact, it can even support it's own weight.
I have here four strong neodymium magnets arranged with the poles facing up
but like poles on opposite corners.
This creates a magnetic weak spot in the center
where the pyrolytic carbon can be stably levitated.
As you can see with this sheet of paper, there is nothing underneath.
It doesn't matter what side it is, as said before,
diamagnetic materials are always repelled by magnetic fields.
Let me move the camera.
As you can see the sheet is levitating about a millimeter off the magnets
and a sheet a paper can be easily passed around it.
Whoops.
It can support of a small piece of tissue.
Superconductors are even stronger and levitate higher than water
or pyrolytic carbon but currently require very cold temperatures.
Pyrolytic carbon however works at room temperature and can be easily purchased online.
I've listed some sellers in the video description.
So that's the amazing property of diamagnetism.
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Alright, so this is the actual speed of the diamagnetic water experiment.
As you can see it's really weak.
