How to Make a Magnetic Brake Tower Thing


Introduction: 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


xacto knife

Step 2: Make the Stand

mark two dots at the end of the 2 by 4
mark corresponding holes on the board
drill on the dots
screw screws into the board so that only the tips are through (i found that that makes it easier to line up)
put the 2 by 4 on the screw tips
screw it in the rest of the way

Step 3: Prepare the Track

if you are using a recycled shower door track clean it off and remove the silicone
cut 2 pieces of packaging tape the length of the track
stick them together sticky side in (you might need someone to help you with this)
line it up with the track so it covers the open side
tape it in place

Step 4: Finish It

tape it to the stand you made

drop a magnet thorugh the top and watch it fall really slowly

you could use it as a science display, or you could make it look sci fi high tech and say its an antigravity chamber.

now with a video
yeah, my hair usually isn't in my face like that



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    24 Discussions


    11 years ago

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

    1 reply

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

    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?

    Congratulations. You've just won the award for'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.

    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.

    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

    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.

    1 reply

    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").

    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

    1 reply

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

    1 reply

    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.

    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)