Inquiry

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Inquiry

• Dave Henry (henryd_at_buffalostate.edu)
• Buffalo State College

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• You have two ears and one mouth use them in
  that proportion.
• Arnold Arons giving advice to a teacher

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A case for inquiry
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A Case for Inquiry

• Constant current batteries and disappearing
  electricity

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Constant Current Batteries

• A common naive conception is that a battery will
  provide that same electric current -regardless of
  what is connected to the battery.
• Instruction is often not effective in changing
  this mental model

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Current Electricity Predict Observe
Explain (POE)
Rank the bulbs in the circuits according to
brightness. (adapted from White and Gunstone,
1992)
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Constant Current Battery

• Teacher Im curious how the electric current
  coming out of the battery for bulb A compares to
  this one with B and C and this one with D and E?
• Paul Well the electric current is the same.
  Its just where it has to run through. Itll
  start at the negative and go to the positive
  obviously, but here it just runs through A and
  goes straight to B. Here it has to run through C
  then go to B then come back.
• Teacher So the current is the same?
• Paul Yes.

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Constant Current Battery

• Teacher How does the current coming out of the
  battery connected to D and E compare to the
  current coming out of the battery with A?
• Beth Its the same.
• Teacher Its the same? And what about B and C?
• Beth The same.
• Teacher If the current is the same from the
  batteries how can B and C be dimmer?
• Beth The resistance of the bulbs as the
  electrons flow through. Not that the kind of
  bulb matters, just it takes... I dont know what
  Im trying to say here.

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A case for inquiry Electricity is used up

• Another common naive conception is that
  electricity is something that is used up.

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Electricity is used up

• Teacher Ok, so if I put an ammeter say before
  bulb C, after bulb C and before bulb B and after
  bulb B. How would those ammeters compare?
• Maggie This one, the one before C, will be
  greater than the one after C and the one after B.

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Electricity is used up

• Teacher How would the ammeter after A and the
  ammeter before A compare?
• Bill The one after would be less.
• Teacher And it would be the same or different
  than the one after the bulb B?
• Bill Itd be the same as the one after bulb C,
  but more than the one after bulb B.
• Teacher What happens to the current then.
• Bill The bulb uses the energy.

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Electricity is used up

• Teacher So if you had a powerful microscope, a
  magic microscope that you could kind of see
  inside the bulb what would you see?
• Bill Electrons go in the wire and go off, I
  dont know, they like get bright so they leave
  the wire, I guess, like the filament so you lose
  them. The electrons would be going in there and
  then bouncing around so that they go off out of
  the filament.
• Teacher So the electrons are creating the light?
• Bill They are the light, yeah.

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Current Electricity novel situation

• Rank the motors in each circuit , A, B and D,
  according to their speed.
• If I stop motor B, what will happen to Bulb C?
  (Why?)
• 3. If I stop motor E, what will happen to Bulb D?
  (Why?)

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• When the answer finally came to me, I was so
  excited. I would come to the end of a very
  difficult process only to find out that the next
  day, my frustrations and confusions would
  reappear with a new lesson. Knowing that these
  activities are all steps to finding out the
  answer to my problems will help me to keep eager
  and open-minded the next time I start to get
  frustrated.
• student after many months of
• inquiry-based physics class

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• All of the puzzle pieces had finally come
  together. The picture was right in front of me.
  I may not have expected the outcome of the
  experiments, but I will remember the results
  because I had seen and come up with the ideas on
  my own.
• student after many months of inquiry-based
  physics class