The Rookery

   The fourth graders had a very busy day today.  It began when each group got a battery, a lightbulb, and a paperclip.  I challenged them to make the lightbulb light.  I think they were expecting a pretty simple solution and many were a bit discouraged.  Then suddenly one group yelped — their wire had gotten very hot but the light hadn't lit.  What was going on?  Eventually, each group discovered how to make electrons flow through the paperclip and then, how to get the electrons to flow through the lightbulb, too.  By looking very closely at the lightbulb and struggling to make the circuit work, students discovered for themselves the basic principles of current electricity.

 We built on that knowledge by creating a "test" circuit and trying out many materials to see if they were   conductors or insulators.  Then we made a switch.  Finally, we talked about electromagnets (and I got to model how to deal with an experiment that doesn't work at all as you expected when I went to show them how to make a simple electromagnet and failed utterly).  We brainstormed which variables I might change to be more successful and I'll return to it tomorrow.

We ended the day with some old phone handsets that had been cut in half.  When these are put in a series       circuit, they function — the sound waves transformed by a switch into electrical current which is then returned to sound by an electormagnetic diaphram in the speaker.  It's really cool.  After getting their own handset to work, teams joined together to make a party line.  P.W. had the great idea to create a phone system for the school by using a lot of alligator clips to reach downstairs.  We'll try it tomorrow. –MMM