Rotation: o Barrier, multiple sources should disappear for rotate wave in water module. What we’ve come up with is to rotate a box that has the horizontal cross section as one face and the vertical crosssection as another face. >>See email. All three views will rotate (Sound and Light show same thing on side as on top) >I'm not sure how to visualize the intermediate graphics for sound & light. -I think the idea is that it will look just like the intermediate graphics look right now. It's just that when it flips over to "side" it will look the same as "top". This is because both sound and light waves are the same from all angles. >Not sure I want to handle what to do with barriers, sources in these cases. >Maybe we should disallow rotation here, and refer users to the 3-d falstad wave simulations..? >>Delete rotation for light & sound. o Should be able to view sound waves and light waves from the side. Vectors on the light panel: We have a representation for vectors in radio waves and we’ve found in interviews that it’s useful to use consistent representations. For this reason, we need to have about a third of the vectors on the graph, remove the black outline and have hollow vectors with a colored outline. The outline should be about twice as thick as it is now. Also the one black vector is misleading. I had a quick informal interview with a student today and they struggled with the significance of the black arrow. Also in the PhET meeting today, I could not make out the arrows on the screen but with radio waves, they are very easy to see on a projector. I’ve attached a screen shot of how they should look. o Photon vectors should not have their tail fixed at E=0, but their middle, so students don't confuse "y" with "E" Maybe e-field vector should be hollow? Units: On all panels the graph x-axis units need to represent a realistic number. The measuring tape already does this so for each panel if you could match the units on the graph to what the tape measure uses. For the y-axis, simple tick marks with no numbers or units will work. o Test at 1024x768 o Test on a Mac. o Add foreign languages. o Add help? o Add correct units to measuring tape. o Right now audio is implemented to play the audio directly at the speaker (not a distance from the speaker.) Should we add 'listener' mode, as in 'sound waves' simulation? o Add correct units to stopwatch. o When a barrier is present, it should be shown in side view as behind the wave. o Faucets should be draggable. Particle View - When you put up a barrier in sound, the particles to the right of the barrier don't go through (this is correct), but the particles on the left of the barrier penetrate the barrier. I suspect that there is a boundary condition on the right side, but not the left? On the sound panel the current particle view is too large and there’s only one red molecule. Let’s use the size of molecules that corresponded to 0.6 on your previous version using the same number of red molecules that were displayed on that version. For some reason the current version is very slow. Something needs to be done to improve performance on this panel. Bug: When you turn the gun off, it goes to solid color rather than black. Would it help speed things up to make the particles smaller? They could be maybe 75% of their current size and it might look better anyway. I would pick a smaller particle size for the particle view. Probably half your current size or a little smaller. Have the bar that connects to the faucets be silver like the faucets and frame of control box. On the speaker the current color doesn't look bad at all. For the light I'd also change to a grey. Detectors: the graph obscures the wave right in front of the crosshairs, I thought we were going to move the crosshairs to handle this (top center)? I thought we were going to detach the crosshairs from the readouts. o Graphs need to be cropped. >>Should graphs really be cropped? Is this just for visual appeal? ############################################################## Low Priority________________________________________________________ - It looks like the particles run away from the speaker and then fill in from behind. I know this is sort of an optical illusion, but there may be a way to minimize this visual effect. I tried to follow a single particle and it still looked like it was running away. Do we want to optionally show absolute values (or intensities) in the wave area (to give a more global idea of constructive and destructive interference)? o I would leave it up to others whether we should show intensity in the wave itself. I don't really have an opinion, but I would lean towards not doing this, since there are already a lot of controls in this sim and I'm not sure what this option would buy us. Maybe in an advanced pull-down menu?? >>This looks like it wouldn't be a useful feature. I'll drop it for now. Make the view angle box narrower. >>This is currently very difficult. Maybe I should forget it for now. - Issue with the light source. (you need coherent light to get interference). The way this is actually done (I think) is to shine a laser through a single slit (or pinhole) and make the light diffract, creating circular wavefronts. Also a problem of scale, since the light should be ~500nm. Maybe none of this matters, but it's something I noticed and should be solved if there is an easy solution. >>We can leave this as a lamp source for now. Let me know if we think of something better. Pressure waves are out of phase (particles are too slow to keep up with pressure). - I did notice that - I was going to mention that high pressure should be where the particles are dense. Right now it looks 180 deg. out of phase. >>I switched the phase by 180 degrees, still slightly off, but maybe good enough?