# A small, portable gravitation shield

Yes, it is a real gravitation shield! Well, not really, but it is a great thing to astonish people at first and then make them remember the electromagnetism they have been taught at school. It is also a great conversation and demonstration piece in a class studying electromagnetism.
Also, it can be done in five minutes if you find the materials.
It DOES nothing, but, to keep it short if a magnet moves near a conductive something it creates electric currents in it. In the tube they  go around the circumference of the tube and create their own magnetic field, which repulses our magnet. And this makes it fall 4 times slower.
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## Step 1: Find the tube

You need a longish (30 cm - 2 meters, it is perfectly your choice, about 1-3 cm inner diameter ) piece of conductive and non-ferromagnetic tube. Aluminium works well, but before buying it search the house, it is very likely that you'll  find it somewhere. I cut a piece of the hanger rack from an old wardrobe.

## Step 2: Now the magnets

Now the hardest, bur not really hard part. You have to find a strong rare-earth magnet that fits in your tube. I really like it with a spherical magnet, but it is left at school, so I used a stack of ordinary ones instead. They should be able to move inside without touching the tube, but there shouldn't be more than 2 mm between the magnets and the walls of the tube (it depends on the strength of the magnet).

## Step 3: Finished

Well, everything is  now, but before showing it to anyone, it is better to understand completely how it works, otherwise you won't impress anyone that much!
When you are sure you understand the theory completely, stick the magnets inside the tube and have fun!
PS I've tried to attach a file with a totally useless something (and it is in Russian), but there is a wonderful picture there that explains everything if you meditate over it for 15 minutes.
токи фуко.pdf(595x842) 257 KB
токи фуко.pdf(595x842) 257 KB
bigb625334 years ago
Isn't this what they use to power those flashlights that you're supposed to shake?
3 years ago
I think you mean those Faraday lights? They operate by having a magnet passing through coils, which causes electromagnetic induction.
2 years ago
neat i like induction especially from the tesla coil Nicola Tesla was a cool guy
gruffalo child (author)  bigb625334 years ago
I suppose not. In the ones I've seen there is just a metal ball inside that makes a contact when the thing is shaken, but I am not sure whick ones are you talking about.
4 years ago
i think he means the ones that have a circle magnet that passes a coil 2 create power
4 years ago
I do believe so.
nerd74732 years ago
I have abunch of capacitors and a bunch of electronics
Dauthiwarlord4 years ago
http://www.youtube.com/watch?v=nrw-i5Ku0mI
signposts4 years ago
For all those wondering what this does i will try to explain. I did this in one of my science classes a few months back and basically when you drop the magnet into the pipe (FYI we use a copper pipe) it creates an electric current similar to a generator. This in turn creates its own magnetic field as it is an electric current and this causes the magnet to slow down. so the end result is that the magnet takes several times longer to come out the bottom of the pipe and thus creates an effect that resembles a "gravity shield" as the gravity appears to have been reduced. Hope this helps someone.
Craig 4444 years ago
Haha this thing is awesome. I honestly have no idea why you would want to make it (besides hitting someone with it) but it's cool. Thanks for sharing!
nb1094 years ago
I think what everyone's getting at could best be summarized as "What does it do?"
franklferg4 years ago
dude its some magnets in a tube please explain the purpose!!!!
steveastrouk4 years ago
Eddy -current damping

Nice Instructable, maybe it should say eddy current damping somewhere (and not in Cyrillic !!)
4 years ago
* thumbs up
gruffalo child (author)  steveastrouk4 years ago
The thing in Cyrillic has very little connection with magnets falling through tubes. It is some strange people's article from a scientific magazine, but it has a nice picture.
gruffalo child (author)  steveastrouk4 years ago
Is something called Foucault currents (I'm really bad with French spelling) the same thing?
4 years ago
You learn something new every day. Thank you ;-)

You are quite right (and so is your spelling)

http://en.wikipedia.org/wiki/Eddy_current
mrmath4 years ago
I'm sorry. I don't get it. Once you have the tube and the magnets, then what?

Also, you have two pics of the magnets in step two, but no explanation as to what the difference is. Can you clear that up, too, please?
gruffalo child (author)  mrmath4 years ago
You just let the magnets fall through the tube and see what happens...
One of the magnet photos is the way I store them- with little plastic circles between them, and the second one is how I use them (they are stronger when closer to each other).
4 years ago
Your instructable is.. incomplete?
4 years ago
You need to explain all of that in the Instructable itself. You can use image notes if you want, but putting text directly into the steps is better.

As Mr. Math said, explaining why this is interesting, what people should see if they build it, and maybe a link to a video, would all make it more accessible.

Remember, you're the only one in the world who already knows about your project. What you're writing here on I'bles is for people who don't know anything about it.
kelseymh4 years ago
I'm on Steve's side here -- if you could add a little bit of theory in English, maybe just a couple of sentences with links to the basic Wikipedia articles, that would be very beneficial to users.
4 years ago
I'm sorry, gruffalo. I have to agree. Even with your explanation, I still have no idea why I would build this. Maybe a video? Maybe some extra IQ points sent my way?