Sunday, January 28, 2007

Homemade Electromagnet Project

Today we tried making electromagnets. It was load of fun! We used a D cell battery, a 3 1/2" nail (not galvanized) and some 20 gauge solid core wire. All you have to do is strip about 1" off of each end of the wire and coil it around the nail. After that you tape one end of the stripped wire to one end of the battery and touch the other stripped end of the wire to the other end of the battery. Voila! An electromagnet. Here's what it looked like.


The lesson is that electrical current (electrons flowing through the wire) creates a magnetic field perpendicular to the direction of their flow. The bigger the battery, the stronger the magnet. The more coils, the stronger the magnet. Try it with a non-magnetic metal like aluminum foil. It won't work.

Do NOT use a car battery and do NOT use electricity off of a wall outlet. You could be seriously injured. You'll also find that if you handle the stripped wire directly as you touch it to the battery it gets very hot. We found that handling just the insulated part was cool to the touch.

You can do fun things with them afterwards like trying to see how fast you can pick up metal objects. Like this.


For more homeschooling fun, visit this week's Carnival of Homeschooling.

14 comments:

Victor Tabbycat said...

Oh, that's helpful... until you get told by homeland security that yur gifin out dangerous information.

Kelly the little black dog said...

When I waqs a kid doing the same thing I used one of those latern batteries with the coiled terminals. That way you didn't have to hold the wires against the battery.

As for the wire getting warm, try running the current through the some steel wool and seeing what happens.

Foxfier said...

*grin* Folks like you are why I want to homeschool, rather than send my kids to (hack) public school.

Scribbit said...

Just in time for the Science Fair next month, I'm bookmarking this one for my boys.

Anonymous said...

How big a magnet would i need to, say, knock out a computer? Cos my next door neighbour uses our wireless and I wanna freeze his pc next time he does.

K T Cat said...

Tureal,

The Scratching Post does not endorse PC attacks. If the guy is using your wireless, just enable your encryption. If you use a password to get on the network, your neighbor won't have access any more.

Anonymous said...

It amazes me that people would build a giant electro magnet to knock out the neighbors pc and probally his own in the process, but not take the time to turn on something as simple as WEP.

Anonymous said...

So what gauge wire would be good to use for a rather powerful small magnet? And what type of batteries perform the best? NiCad? Lith? I'm looking for longetivity of battery life while withstanding a decent current draw ... The ideal electro magnet would be able to push away 3-5 lbs. Could that even be done with small batteries and small gauge wire?

Anonymous said...

Victor...none of this was dangerous information, this stuff gets taught to young kids in elementary school.

To the guy/gal wanting to home school please re-think that, if the schools in your area are really bad try private school. People that were home schooled almost always grow up to be very very socially awkward and have trouble forming relationships of any kind and 9 times out of 10 the education they get is terrible or at least it seems like it's extremely sub-par when when they get to college

K T Cat said...

Good comment, anon. My kids go to Catholic schools. Surprisingly, there are fewer knifings and more learning there than at public school. Go figure.

Anonymous said...

Cool, how do you determine how much a magnet will lift? I wanted one for picking up the nails around our new roof, but rare earth magnets (of any useful size) are very expensive.

Anonymous said...
This comment has been removed by a blog administrator.
Bababooey4mayor said...

lol i live in windsor, ontario. and in the whole city, the only school to have somebody get stabbed was my old school F.J. Brennan catholic school. also only blocks away from where constable John Atkinson was shot a few years ago, by a former Brennan student

Anonymous said...

Dear anonymous, How many home schooled children have you actually interacted with? Too many people are willing to generalize with a sample size of one or two!