Re: [Phys-l] Student Misconceptions

[Philip Keller <PKeller@holmdelschools.org>]

I would not just calll them preconceptions -- I'd call them post-conceptions too, stubborn buggers!  

For example:  AFTER we have studied free-fall, AFTER a test which most students did well on, and after we have learned to analyze basic postion and velocity graphs, I tell my studetns that we are going to drop a picket fence past a photogate and the computer will graph the velocity.  But we are going to do this 3 times, hanging 100, then 200 and then 300 grams from the picket fence.  I ask these students to predict what the data will look like.  Most common prediction (by far):  three lines, of three slopes: low, medium and high.  Then I make them predict the slope of the lines.  Most pick three random but ascending numbers.  Then I let them compare their answers.  I will say that though only maybe 1 in 10 students has picked three identically sloped lines, once the others see that prediction, it is quickly recognized as most likely.  Then they do the experiment and of course all three lines have nearly the same slope, all in the 9.8 neighborhod.  

The point is that most of my students believe that heavier objects fall faster even after they have "learned" otherwise.  And if I wait 3 weeks and then ask again, I bet some of them still believe it.  Stubborn indeed.
________________________________________
From: phys-l-bounces@carnot.physics.buffalo.edu [phys-l-bounces@carnot.physics.buffalo.edu] on behalf of Joseph Bellina [inquirybellina@comcast.net]
Sent: Thursday, September 29, 2011 11:25 AM
To: Forum for Physics Educators
Subject: Re: [Phys-l] Student Misconceptions

Perfect example.

Joseph J. Bellina, Jr. Ph.D.
Retired Professor of Physics
Co-Director
Northern Indiana Science, Mathematics, and Engineering Collaborative
574-276-8294
inquirybellina@comcast.net




On Sep 29, 2011, at 11:03 AM, chuck britton wrote:

> A classic mis/pre-conception that everyone must deal with eventually
> is Aristotelean thinking.
>
> The 'Natural' state of every object it to be at rest and to remain at
> rest until some outside agent makes it move.
>
> Who can deny the reality of this!!!! It JUST makes SENSE ! ! ! ! !
>
> Every successful intro physics student will learn to recite Newtons First Law -
>
> BUT VERY FEW STUDENTS WILL INTERNALIZE IT ! ! !
>
> The FCI is an excellent measure of how just poorly this basic concept
> is internalized.
>
> There is NO denying these results.
>
> It easy for those of us who teach - to think we're doing a great job
> - but how many of us are willing to actually measure the results -
> for fear of seeing how difficult it really IS to create a fundamental
> paradigm shift such as this.
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