i've got an idea for something but know nothing about science so i hope you can help!

iWheeler

sorry if this thread is in the wrong place..

basically it's to do with electro magnets.. can you control the strength of them by something like a pedal? as in if you gradually push it the strength gradually increases?

also would it be a health risk if you were right next to electromagnets or had something on you the magnet will pull for long periods of time?

sorry im being very vague not sure how to ask about what i need to know!

thanks in advance if you can help

sophiecentaur

Hi and welcome
I can't help you much except to say that an electromagnet uses an electric current. The current can be controlled, as with motor speed, lighting and heating control by varying the voltage of the power supply.
This is easy to achieve for a small electromagnet but many industrial and scientific electromagnets use huge amounts of Current so the power supplies are specialised equipment.

mfb

As far as I know, magnetic fields of reasonable strength are no problem as long as you and the field do not move with respect to each other. "Reasonable strength" here means "everything you can achieve", which is below 5 Tesla. Moving in strong magnetic fields (like several Teslas) can cause problems, as this can induce currents in the body. Howevery, you would need quite a large and strong magnet to get in this region.

This is vague, too, like the question itself :p.

sophiecentaur

I can say that some electromagnets that are very easy to build can be stunningly strong - if all you want to do is to 'hang on' to a piece of steel. A few amps through a couple of dozen turns which are wrapped round a 'C Core' out of a drawer in a School Prep Room will hold up a mass of many kg. That is actually very impressive but it won't 'attract' that load from more than a few mm away.

The ultimate in 'powerful little electromagnet' has to be in the pilot flame protection valves in gas heaters etc. A small thermocouple, in the pilot flame, produces enough current in a solenoid to hold open a gas valve against a fairly strong spring for years of operation. Such a simple invention and someone deserves credit for even trying out the idea. I would have rejected it out of hand if I'd been asked.

iWheeler

wow thanks for the fast replies very helpful!

this will probably sound very strange but.. say you had a jacket on that had metal in it and a few electromagnets around you that were strong enough to pull you in certain directions.. (enough so you can feel it pulling you) is this possible and most importantly safe?!

haha sounds quite funny when i put it like that..

thanks!

DaveC426913

You are at great risk, not from magnetism, but from blunt force collisions. You will get slammed into the magnets.

Try this on a very small scale with a paperclip and a couple of permanent magnets arranged in a circle. If the paperclip gets within a certain distance of a magnet, you will be too slow to prevent the rapidly increasing force from yanking the paperclip right to the magnet.

Borek

They don't pull you, they pull the jacket.

iWheeler

that should be a problem as the person would be fixed to something like a seat within a circle of magnets, the problem i was wondering was if the magnetism could be harmful to you, it would only be a enough so you could feel it pull you in different directions.

iWheeler

shouldn't**

iWheeler

sorry yeah i meant when it pulls the jacket it would feel like you are being pulled

DaveC426913

You can edit your own posts, BTW.

They'll definitely feel it all right. They'll get whiplash.