Re: [Phys-L] [SPAM] Re: The Make-Believe World of Real World Physics

["John Clement" <clement@hal-pc.org>]

But in math they don't interact with graphs.  Math uses the number plane, so
they are really using maps.  In the number plane the distance between 2
points has a meaning, but on a graph it usually has no meaning because the
units for the two axes are different.  Basically the research which goes
back to the 70s or perhaps before shows that they MUST learn to translate
between pictures (motion maps), graphs, descriptions and lastly equations.
Many teachers in the modeling program have found that getting students to
solve problems pictorially or graphically works better, and then later they
use equations more intelligently.  The UMPERG research group emphasizes this
in their Minds on Physics text series.

The ILDs created by Thornton and Sokolff are very helpful in getting
students to understand that there are no kinks in the V-t graph of a ball
thrown up and that acceleration does not go to zero at the top of the
trajectory.  So there are some research based methods of treating some of
these problems, but like all educational treatments they are not 100% and
they always work better for students who test at higher levels of thinking.
So getting students to higher thinking is really one of the important
solutions.

John M. Clement
Houston, TX


> Allow me to jump in here about graphs. I think kids know how 
> to graph functions in their math classes. Then they come to 
> physics, and it's a whole new ball game. So difficult for 
> them, especially with slopes. Then, I give them a few 
> constant slope lines on a "d-t graph" and ask which has the 
> highest acceleration. They just confuse the axes and think 
> it's a v-t graph (like something they've seen before). Some 
> just never understand graphs. Kids generally find math 
> problems the easiest. Concepts and graphs are more difficult.
>
> Not sure what the solution is. Kids have difficulty thinking 
> in school these days, which is why they find physics 
> challenging. It requires them to think in ways they never 
> have before. And thinking requires effort. And they have 
> other classes, XC activities, and social lives.
>
> What to do???
>
>
>
> Phys-L@Phys-L.org writes:
> > I think there is real value in getting students to use graphs to 
> > understand situations and solve problems.  But first they have to 
> > understand graphs, and I don't think enough time is spent in math or 
> > physics on that.  Do students understand what the points on 
> the graph 
> > represent, do they understand what horizontal and vertical intervals 
> > represent?  How do we know they do understand.
> > These graph solutions can be done with constant velocity 
> problems first 
> > and then advanced to more complicated situations as the student 
> > understanding develops.
> > Average velocity also has extra meaning when you look at 
> graphs and begin
> > to talk about slope.   I suspect your concern has more to do with the
> > abstract nature of the way the problem is presented, rather 
> than about 
> > the content.  What say you?

>