Saturday, May 3, 2014

Turned on Students

I finally found the topic that can intrigue most students - electricity!

Here during the last 3 weeks of the school year, I started my favorite physics topic, and it turns out the students are really turned on by it too. Students who would sit at the periphery are joining in the activities, worksheets are being completed, quizzes are getting a much higher grade average, and expressions like "wow" and "eee" and "come look at this!" are common.

As usual, I've been using the Teaching Physics through Toys book, as well as some activities I've used before, which I've rewritten for this class. As something new, we are using some sections of Active Physics, which I received as a class-set a couple of months ago, and just now started to use. The students love it, and some wish they could take it home to read the Green Pages. No one has ever asked to be able to read something before! Some have even asked about where to read in the Conceptual Physics book they have at home.

We have used hand-cranked generators, batteries, magnets and the sun to generate electricity.
We've studied what happens with magnets when they come close to i(which I put into well-sealed plastic bags because of previous experience) and compasses. On an Active Physics quiz, most correctly chose "compass" when asked what to use to detect a current in a wall.
We've made magnets by wrapping wire around straws to make solenoids, which we've powered with the hand generators to make weak magnets - and they accepted that they were weak.
We've made 2 different kinds of mini-motors, and then experience "real" motors in other settings.
We've taken apart the Operation game to see what makes it light and buzz (including a motor, which not all could identify at first.)
Students can use words like power source, series and parallel circuits (which I illustrated with stories about finding the burnt out Christmas tree lights in the series light strings of my childhood - and discovered that a couple of students still use these at home or at Grandma's.) Most understand that static electricity "stands still" (based on the Latin word) while and electric current "runs" (using Spanish.)
We used some fun "energy balls" that lit up and buzzed when the 2 poles were touched to make human series and parallel circuits. I've left out the Arbor Scientific catalog so they can see where all these fun things come from.
They've used balloons to find how electrons are gained or lost, and can explain that electrons are negative, so "gained" means "more negative." I told them that it's Ben Franklin's fault getting positive and negative backwards, that causes misunderstandings, and that I had a lot of trouble with that in Chemistry, so they have an advantage over their future chem classmates because they can tell the difference. We also pulled in a bit about adding and subtracting negatives, which suddenly also made a lot of sense.
And they know that static electricity and magnetism are both similar, but very different.

But it was when I put a big box of wires, batteries, light bulbs, small motors and tools on their tables that they really got excited. First they all made a switch out of a 3x5 card, a paper clip and pronged fasteners and washers, so that they (that is, most of them) kept their circuits off while they were building them. A few got eager just putting things together to see what would happen - including burning out an alligator clip with a short-circuited battery. Some strung out all the components they could find (and most got the batteries going + to -). One group figured out the parallel circuit on their own, and then added new parallel groups until they ran out of components. Such excitement - and EVERYONE was participating. (It didn't hurt that my supervisor just happened to walk in just as the excitement was greatest, and I was showing a student how to straighten a wire with pliers.) Even the girls got into using screwdrivers and pliers, after some announced that that was a boy thing.

On Monday the groups will get to use multimeters and I hope we'll get in a little introduction to Ohm's Law before we have to move on to finals review.

I'm seriously considering starting physics with electricity next year. If I can hook them with that, maybe they'll stay connected for Newton as well!


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    1. I'm glad you found it useful! I've moved on to another school, mostly teaching math and chemistry. I'd forgotten about that post and the fantastic energy in the classroom. Thank you for reminding me about it!

    2. I'm glad you found it useful! I've moved on to another school, mostly teaching math and chemistry. I'd forgotten about that post and the fantastic energy in the classroom. Thank you for reminding me about it!