True North

Today at the elementary school we became familiar with magnets.  Grades 1-3 did more of an exploration than a specific lab or task.  I was amazed at how excited they were to play with magnets!  They discovered all kinds of creative things like an "antigravity" device and moving a magnet on a desk using another magnet under the desk, which could not be seen by casual spectators.  I tried to structure their exploration around some basic questions asking how magnets behave in ways similar to and different from charged objects, which was our previous session, and after a lot of exploration we discussed this as a group.    In addition to run-of-the-mill magnets, I brought in one really strong magnet, some small pieces of steel, a plastic case with iron filings, and some compasses.  I sketched how Earth has a magnetic field much like the one shown by the iron filings around a magnet, but we did not talk about compasses much more than that. (I know the kids had some training in the practical use of compasses at their field site. )  The compasses were used mostly as devices which could be spun like crazy by the handheld magnets!

For grades 4-6 I had planned a more directed activity after a shorter period of exploration, because most of them had already played with magnets at some point.  The activity was to build a compass by magnetizing a small piece of steel and then allowing the small piece to move freely.  The moving-freely part was supposed to be accomplished by floating it in water, which a small piece of steel can actually do thanks to surface tension (which formed a mini-lesson in itself).  It seemed pretty easy to get it to float when I practiced it at home, but it was very difficult at school.  The kids got discouraged and played with other aspects of magnets when I wasn't at their table to help them.  I still think it's a good lab, but next time I have to find even smaller pieces of steel, or some other way to remove friction.  I made an on-the-fly attempt at removing friction by hanging it on a string, but the string was too stiff to allow it to rotate freely.  Some people suggest sewing needles, but that seemed a bit dangerous.  I guess I could just blunt the needles before use.

This blog entry is a bit short, without the usual diagrammatic explanation of everything we discussed, but I have to save time this week.  Someday I hope to write a longer explanation of everything we talked about.  We did discuss in quite a bit of detail, because we had 45 minutes per group, which is now the norm since about mid-February.  This amount of time really facilitates thought and discussion.