# I need help for a project

• November 8th, 2017, 10:28 PM
Scienceman22
I need help for a project
Ok so I got a 12 inch long copper pipe, 3 small disc shaped neodymium magnets stuck to each other and I drop it through the tube, with copper wire around it. I use a voltage meter and a homemade galvonameter. I get no current detection response, so I take the copper wire out and just make a loop of them and try sticking my magnet through them and out fast because of faradays law. Still no response, so please help me! I may be doing something wrong, or the current is took weak to detect. If anything is unable to answer, then I would like to find a way to calculate the amount generated.
• November 9th, 2017, 08:58 AM
exchemist
Quote:

Originally Posted by Scienceman22
Ok so I got a 12 inch long copper pipe, 3 small disc shaped neodymium magnets stuck to each other and I drop it through the tube, with copper wire around it. I use a voltage meter and a homemade galvonameter. I get no current detection response, so I take the copper wire out and just make a loop of them and try sticking my magnet through them and out fast because of faradays law. Still no response, so please help me! I may be doing something wrong, or the current is took weak to detect. If anything is unable to answer, then I would like to find a way to calculate the amount generated.

I'm not surprised it didn't work with the pipe, as that is a conductor, so any induced current would be induced in it and not in the coil of wire, which is outside it.

I don't what the setup looks like but you have to cut lines of magnetic flux in order to generate a current. Also if one side of the coil cuts flux in an equal and opposite sense to the flux cut by the other side, the two will cancel, resulting in no current. So I think you have to be careful how you orient the magnets with respect to the coil.

But now that I read your post again, did you in fact make a coil of wire or just a single-stranded loop? A single strand on its own is unlikely to cut enough flux to be detectable. So that could be another reason.
• November 13th, 2017, 09:47 AM
perdurat
Quote:

Originally Posted by Scienceman22
Ok so I got a 12 inch long copper pipe, 3 small disc shaped neodymium magnets stuck to each other and I drop it through the tube, with copper wire around it. I use a voltage meter and a homemade galvonameter. I get no current detection response, so I take the copper wire out and just make a loop of them and try sticking my magnet through them and out fast because of faradays law. Still no response, so please help me! I may be doing something wrong, or the current is took weak to detect. If anything is unable to answer, then I would like to find a way to calculate the amount generated.

you're mixing up two experiments:
dropping a magnet through a copper pipe: in theory it should slow down the magnet, the falling magnet introduces electric current in the pipe, which will produce a magnetic field in the pipe, which counteracts with the magnetic field of the falling magnet.drop the magnet out of the pipe from same height to compare the time
moving a magnet past a copper wire:make a coil of the copper wire (50 turns would suffice to be able to measure the effect),move the magnets in and out the coil