Electromagnets - Saturday Science

Hi this is P here for my second Saturday Science entry - this time on electromagnetism.

artist's impression of an electromagnet by P

 A little while ago Moomintroll was playing with a magnet on a string and picking up various items.  When it came to getting them off the magnet some vigorous shaking led to the topic of magnets that you could switch on and off.  Well, here we are on a Saturday and it's finally time to do the experiment!  We started looking at some of Moominmamma's art, and a bug on it seemed to come alive!  Actually, a bug paperclip with a magnet underneath (and some happy memories of a magnetic car driving game as a kid).

How strong are our magnets?  Well, they can hold a paperclip suspended in the air.  SnorkMaiden discovered she could make the paperclip spin by pulling the magnet in and out.  Interesting stuff!

What about electromagnets?  We watched a great video of one in action at a scrap yard

and then made some from a variety of bolts, some insulated wire and a C battery.  Talked a little bit about how all electricity generates a small magnetic field, and coiling the wire around a bolt increases the effect.  We picked up paperclips and a nail clipper and saw that some magnetism remained in the bolt for a short while even when the battery was disconnected.  Watch out for hot wires!

Tried to make a solenoid from wire wrapped around a nail in a straw.  It was much more fun to short out our battery-operated doorbell and watch the doorbell solenoid striker hitting the metal tone bars!  We finished with another video from my new science hero Derek Muller from Veritasium.  We strayed into induction theory, but left with the great image of a levitating BBQ plate