How to make a magnetic brake tower thing

to make magnets fall very slowly.
good for convincing people you found a form of antigravity
(no, it isn't antigravity)
now with video

Step 1 Materials

for this you will need;

shower door track, or similar shaped aluminum or copper thing (the thicker the metal the slower the magnet will fall)
clear packaging tape
neodnium magnets (need to fit into the track)
plywood board
2 by 4

tools;

xacto knife
drill
screwdriver

Comments

[usuck]

Thats prety cool so u could like put a magnet in a paper plane and call it "landing thrusters"

[Scout Jinx]

A strong enough magnet for that would be too heavy to put in a paper airplane.

[lowtherjustin]

copper and aluminum dont conduct magnetism right?

[jester_rob]

I'm just throwing this out there and if im wrong someone tell me, but doesn't this work because the moving magnet creates an electrical current which in turn creates a magnetic field that slows the magnet?

[chriskarr]

Congratulations. You've just won the award for Instructables.com's longest unanswered question finally being answered. You are correct; the magnetic field induces an electric field in the metal near it which causes a magnetic field opposing the permanent magnet's downward fall.

[dombeef]

COOL lol

[Lord_Vader]

Though they aren't ferrous this principle still holds because they are conductors-try it with a copper or aluminum pipe, it adds to the flair lol.

[AlexTheGreat]

it is aluminum

[AlexTheGreat]

they aren't ferrous, if thats what you mean

[magma6]

For information, the phenomenon is a demonstration of the Lenz's Law.
Explaination and video of the retail version of the same "toy" on this page

[TheTruth]

This principal is used in elevators. If the cables snap, the magnets cause them to descend at a limited rate, using the metal elevator shaft as the conductor.

[AlexTheGreat]

cool i didn't know that

[FrenchCrawler]

When I was little, we used to "roll" a little plastic ball that had a magnet on the inside (I don't even know what it went to) down the front of the fridge. It slowly made it's way to the ground much like this instructable (we used to race two of the "marbles").

[PeterTheUnGreat]

Is this the same principal that some of the vertical drop fairground rides use? Neat, simple demonstration. Now someone just needs to come up with a project which uses this trick to solve a problem. Pete

[_soapy_]

Magnetic brakes on buses and trains already use this. There is no pad to burn out, as it is frictionless. (I'm not talking about regenerative brakes as found on electric cars, etc. but regular deisel buses - http://www.mayr.de/english/p_old/brakes/roba_q/roba_quick.htm is an example)

[lowtherjustin]

how would thicker aluminum or copper make the magnets fall slower? maybe I missed something

[_soapy_]

The thicker walls have a higher conductance, and so bigger eddy currents form, using more power. Another way is to make the magnet a tighter fit in the tube, as the field will be stronger at the surface then.

[Lord_Vader]

This is just obeying the laws of Physics like everything :) When a magnet is in motion its magnetic field is in motion as well. Any change in a magnetic field through a closed circut will generate a current (this is how motors work and the reverse, genorators.) So when the magnet is falling through what is essentially a hollow metal tube, current is being genorated around the outside of it. Since you can't just create energy from nothing the energy that is used to create that current is taken from the kinetic energy of the falling magnet. That's why it falls slower. If you break the circut current will no longer flow and the magnet will fall at a normal rate (given that it isn't just adhearing to the metal surface on the outside)

[Tool Using Animal]

cool, a hysterisis effect I presume?

[AlexTheGreat]

actually I don't know how it works

[zachninme]

Wait, isn't this techinically anti-gravity?
(Not to be picky...)

Cool! To up the effect, encase the magnets in something the make them not appear to be magnetic. Plasti-dip?

[AlexTheGreat]

my camera doesn't have video. my brothers does, though. if i can find his camera i'll add a video

[gigman]

Ya id love to see a video it looks pretty cool. Any way it looks like it could be turned into some kind of cool art project/scupture type thing.

[TheCheese9921]

videos please