I thought I would post a few labs or activities that have been big winners with my students in engagement and learning, whether or not I designed them. This one comes via Cornell’s Center for Nanoscale Systems Institute for Physics Teachers (CIPT). (Do a find for “foutan”* on the page.) There are parts lists, lab handouts, and teacher notes available there.

Here’s a hot tip from the author, Jim Overhiser: short dowels on the corners (as pictured) make for good stacking.

Update: Here’s a nice redesign they’ve made at Cornell.


What came before:

  • Students lit a bulb with a battery and a wire
  • Students dissected a bulb to trace the loop
  • Students set up series and parallel circuits to observe brightness of bulbs and generalize rules

What they learn with this activity:

  • Utility of circuit diagrams
  • Gain comfort with diagrams
  • Gain comfort with series and parallel
  • Trouble-shooting, such as finding that two bulbs are equally bright — are they in series or in parallel?  Unscrew to test.

Why I love it:

  • Lighting the bulbs is an engaging puzzle that motivates the need for circuit diagrams.
  • Students are tracing paths on the diagrams, reinforcing a good model for current.
  • Instant feedback and revision  (The bulb didn’t light! Try again…)
  • Students come out with good feel for series and parallel.
  • Boards can be used in other settings for quick set-up of many simple circuits; students like the quick usability.
  • Students loved this and were wildly productive for a solid 90 minutes.

Some notes:

  • Some students will want to approach this somewhat randomly — flick several switches, then look up what’s lit.  Watch for and cheerfully disarm this practice; they won’t learn much that way.
  • The leads from the 9V are usually the least hardy components.  I change the batteries.
  • Not everyone has to finish the first page.
  • There are plenty of sophisticated puzzles in the mix.  They are not in order of difficulty.
  • I projected the diagram on the white board, and students would come up with markers to work through together, sometimes across groupings, on the challenging ones.

How will you know if students are applying a viable conceptual model for current?

  • Have them rank these circuits according to the brightness of bulb A.  (Note that we do all this before introducing any formulae; they come later.)

*Foutan: The person (a former grad student at Cornell?) who designed this ingenious circuit.  Pronounced like the bed, futon.