o Graphs need to be cropped. o Test at 1024x768 o Test on a Mac. o Add correct units to measuring tape. o Add audio to sound. o Add correct units to stopwatch. o Barrier, multiple sources should disappear for rotate wave in water module. Wave Interference: notes from phet meeting 4-4-06 o When a barrier is present, it should be shown in side view as behind the wave. o Faucets should be draggable. o Photon vectors should not have their tail fixed at E=0, but their middle, so students don't confuse "y" with "E" o Should be able to view sound waves and light waves from the side. - 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? - 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. Bug: When you turn the gun off, it goes to solid color rather than black. Maybe e-field vector should be hollow? 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. I would also like to add a reset button to each screen because you can screw around with the barrier and get situations that appear to be a steady state but after a very very long time, they seem to calm down. The amount of tiem it takes to calm down, however, is not reasonable. I waited 10 minutes after creating the second one in the attached screen shot and it still wasn't back to a sine wave. I took these screen shots about 30 seconds after scooting the barriers back and forth very quickly. o Intensity readers should be constrained on the x-axis when in side-view. >>This sounds like a lot of work. Let's just disable them instead. Is it possible to get some sort of switch or button as the on off's for each panel? >>I think the "on" "off" checkboxes we have now is very clear, and looks good. >>Let's become more strongly motivated before changing this, and also have something >>extremely concrete that we're sure will work. 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. 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. 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?