Model rewrite

[jonathanolson]

The current model code is unnecessarily complicated. It should be based off of the fixed-timestep model with two tunable parameters (tension, damping). Another layer on top will handle interpolation between these model frames for display, and driving its speed (so we won't need timer workarounds, slow motion will be an easy feature, etc.)

How pulses and oscillation are done should be cleaned up, names should be improved, and all of the dt workarounds (stepDt, minDt, fixDt, dt, and interactions) should be unnecessary.

[patricialoeblein]

I am not sure if this is part of this issue or should be an new issue. A PhET user commented on my activity using Waves on a String (http://phet.colorado.edu/en/contributions/view/2819) I deleted the comment and wrote him a note that I forward his thoughts to the html5 team. I checked the Teacher Guide on the sim page and there are no notes that would have helped him with interpreting the sim less mathematically. I believe we probably have notes or emails where we have addressed this issue previously, but I am not sure where that would be. I plan to cc phethelp when I email him .

• User [email protected], William Grelck, commented on Waves on a String (Inquiry Based) by user [email protected]: I find it very disturbing,that calculating the wave velocity in 2 different ways don't fit! Calculating the wave velocity by pulse measuring doesn't coincide with calculating by wavelength and frequency. I also find it annoying that the frequencybar is not displaying the actual frequency, neither in Hz(1/s) or in 1/min.

Here's what I put in the email:
William,
I read your comment on my activity. I believe that you meant to send a note to the sim design team and not really comment on my lesson, so I put a report in for you and deleted your comment from my lesson. My lesson is written to use the sim “as is”. There is a team presently working on re-writing the sim in Html5 and I thought they might be interested in your thoughts.

Just for you information as you move forward using the Java version of the sim. The sim is meant to be qualitative and the units are not aligned with standard units because the simulation does not run in real time. The point of the sim was to make traditional demos be more easily demonstrated without the constraints of real-time.
Trish
PS you might like to try Fourier Making Waves http://phet.colorado.edu/en/simulation/fourier for a more quantitative sim