o Intensity readers should be constrained on the x-axis when in side-view.

o Should we show intensity readouts anywhere, or just wave values?

o The single frequency/amplitude controller should control both oscillators when there are 2.

o When there are 2 wave sources, they should always be in phase.

o Show intensity on the screen as default
    Optionally show fluctuations.

o We could get rid of edge effects by maintining a higher lattice than is shown on the screen.

o Add correct units to measuring tape.

o Add correct units to stopwatch.

o Barrier, multiple sources should disappear for rotate wave.

Probably right. Maybe rotate wave should be grayed out with barrier or
multiple sources - otherwise, it will seem strange that all these things
disappear when you rotate.

o Intensity readout titles should depend on the module e.g. "E-Field"

Wave Interference: notes from phet meeting 4-4-06
1. View angle slider should have labels "top" and "side" and snap to one or the other when released.
    No numbers on this control.
2. In side view, drops should disappear completely instead of incrementally.
3. Barriers in the play area should be draggable.
4. When a barrier is present, it should be shown in side view as behind the wave.
5. Show a dotted gray line on intermediate rotation graphic to signify the cross section.
6. Could show intensity on detectors instead of displacement (ask Noah P)
7. Faucets should be draggable.
8. In particle mode, there should be a smaller number of red particles.
9. In the speaker panel, the speaker cone should move (see Ron for graphics).
10. For the photon panel, users should be able to view with or without arrow vectors.
11. Should be able to view sound waves from the side.
12. Photon vectors should not have their tail fixed at E=0, but their middle,
    so students don't confuse "y" with "E"

    - 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?

- Issue with the light source. I'm not crazy about the laser gun, but I
don't think a flashlight is physically correct either (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.

Okay, I'll add a switch to detectors to show intensity.  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)?

Sound side view:
By sinewave view, I mean a sinusoid that represents the sound pressure vs.
distance from speaker. This is analogous to the light wave that also has a
sinusoid representing E-field.

Intensity:
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??

- The speaker should move when creating the sound wave (at least, the
speaker cone should move).

- 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.

-  When you change the wavelength of light, it resets rather than continuing
with differently colored ripples. Also, when you turn the gun off, it goes
to solid color rather than black. Also, I'd rather have a flashlight than a
gun, unless there is a compelling reason to make it a gun (besides
supporting the military-industrial complex).