Monday, December 19, 2011

Magnet School

A simple electromagnet which can be turned on and off with a switch.
Played with magnets today.  Probably should have done this before electricity but that would imply way more planning that has actually gone into these classes.  Today's lesson was cobbled together with a visit to Radio Shack (thank you, Vardell!) and some experiments found on internet sources ( and had way fun.

1) The girls experimented a variety of metallic objects to see what would be picked up by a magnet (random bits from around the house: monopoly pieces, matchbox cars, tent stakes, bobby pins, coins, keys, batteries, ornament hooks, nails...some things from Bob's tool box-lug nuts? lotsa stuff.)  this took more time than I thought it would because it was fun.

2) We made compasses, by first magnetizing embroidery needles from the first activity and floating them on cork disks.  This was fun, but not a great way to find north due to all the metal objects still on the table, and the metal table frame.  It was more fun to push the little cork boats around with magnetized junk.  One interesting point--the "N" end of our compass points to the North Pole of our earth, which is itself a giant magnet.  But, we know that opposite poles attract.  Thus, we see that the earth's North Pole is actually its magnetic SOUTH pole.  I am pretty sure I never knew that. Did everybody know that but me?

3) We observed the shape of a magnetic field by dumping iron filings out on glass, and putting two attracting magnets underneath.  The filings obliged by lining up along the magnetic field lines.  This was also fun to play with, waving magnets above and below the filings.  We washed up really well after this.

Nancy Drew approves of this experiment.
4) Next, we learned that electricity and magnetism are related.  Moving electrons create magnetic fields.  We talked about electromagnets and Maglev trains.   Vardell demonstrated a simple motor and then each girl built one to take home.  Vardell had pre-drilled holes in some nice sections of cedar plank, and four heavy gauge wires went in each one.  Oh, do you like those bullet casings?
They had a job to do unrelated to their original purpose--providing a frictionless stopper for the spinning wire coil.  Vardell just happened to have some extra bullet casings lying around the house.

A cork was used to make the wire coil.
LED lights were just a little bling, not needed but surely enjoyed.  These clever devices took a little time to put together, but the girls could complete each step from coiling the wire, to attaching the batteries.  It took some tweaking and patience, but the reward was big when the motor started running.  Apologies if I am not using the right names for some of the equipment and concepts--sorry, Vardell!

But you can see it was a fun class.  How have I made it this far in life without a battery pack and a volt meter?  Dear Santa....