Re: [Phys-L] Animation of motion in a potential energy well

["Rauber, Joel" <Joel.Rauber@SDSTATE.EDU>]

Bruce,

You understood my comment quite well.  I tried again and it works as you describe and as I suggested.  I'll assume that I had a mental hiccup and wrote an email too rashly. 

Incidentally, I've had trouble in the past using firefox in a seamless fashion with your glowcube programs, but the latest edition of firefox that I installed last week (22.0) in combination with a new computer, worked and apparently seamlessly :-) 

Joel

-----Original Message-----
From: Phys-l [mailto:phys-l-bounces@phys-l.org] On Behalf Of Bruce Sherwood
Sent: Monday, August 05, 2013 11:03 AM
To: Phys-L@Phys-L.org
Subject: Re: [Phys-L] Animation of motion in a potential energy well

Not sure I understand your suggestion. I think I made a well like yours:
Starting at upper left and dragging to the right, I drew a trapping well, then turned downward and descended way below ("-infinity") at the lower right. When I click at an altitude corresponding to an energy that would give a bound state, I see oscillations in the trap unless I click to the right of the rightmost contour, in which case I see an unbound motion, which I think is what you want, no?

In playing with the program I had found it convenient to permit clicks anywhere to establish the energy level, and then start the particle in the nearest region, with zero speed. But perhaps I've misunderstood your idea.
If so, perhaps we could discuss this more offline.

Glad you liked it!

I'll comment that VPython is much more mature than GlowScript, and the computational environment for Python is far more mature than for JavaScript (whose history until recently was mainly for making web pages dynamic). But for me there's a charm in being able to post a URL and have colleagues try something just by clicking the link (and react to the program), as there's a sizable barrier to asking colleagues to install Python plus VPython and download the application program and run it. On the other hand, not everyone has an up-to-date browser installed, and a graphics card with GPUs, which GlowScript's use of WebGL requires.

Here are other recent GlowScript implementations of some VPython physics demos that you might find interesting:

http://www.glowscript.org/#/user/Bruce_Sherwood/folder/MI/program/02-NewtonGrid

http://www.glowscript.org/#/user/Bruce_Sherwood/folder/MI/program/04-SpeedOfSound

http://www.glowscript.org/#/user/Bruce_Sherwood/folder/MI/program/01-SpaceStation

http://www.glowscript.org/#/user/Bruce_Sherwood/folder/MI/program/24-Radiation3D

Bruce


On Mon, Aug 5, 2013 at 8:54 AM, Rauber, Joel <Joel.Rauber@sdstate.edu>wrote:

> Great animation!
>
> Suggested improvement:
>
> I drew a PE that had a small well to the left and then decreased to 
> -infinity to the right of the well.
>
> Clicking at an altitude that could trap the particle in the well; 
> caused the program to assume it was so trapped rather than in the 
> region to the right where the motion would be unbounded.  So I would 
> alter the program to assume that where you click (left <->right) is 
> the initial location of the particle in order to take care of cases 
> where a given total energy might be a particle that is localized or one that may exhibit unbound motion.
>
> Cool animation though, even as is.
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