Doppler and stuff

On Friday last week, we finished up (or got darn close to finishing up) the lab we were working on with sound waves.
We also discussed some other sound phenomena, specifically resonance.
We played with Chladni plates,
you can find a simulation here that is less "cool" but models the same behavior without the annoying sound. Some images are here

The homework handed out on Friday includes a question asking you to examine beat frequencies.
There are several good simulations out there to see/hear this.
Here's one to learn and hear the waves interacting: http://www.school-for-champions.com/science/soundbeat.htm though there is more math than you need.

Here's a good simulation to "see" the interference of the two waves:
http://www.mta.ca/faculty/science/physics/suren/Beats/Beats.html

Here's another great one, but you'll want to change the frequencies to lower values.
http://www.lon-capa.org/~mmp/applist/beats/b.htm

This one let's you type in "500 Hz" for the first, and then pick the difference (delta).
http://webphysics.davidson.edu/faculty/dmb/Beats/Beats.html?T1=500

But this one (finally!) is probably the most straight-forward for the assignment:
http://www.walter-fendt.de/ph11e/beats.htm


Monday, we discussed Doppler effect.

In water waves, in sound waves, specifically for high speed aircraft, and then also for doppler radar (weather stuff) and finally a concept called "galactic redshift" where we observe that light from distant galaxies are redder than we expect, indicating that they are all moving away from us (the doppler effect for light causes a shift in the spectrum (ROYGBIV) towards the red end when things are moving away from us).

Here's some good stuff for doppler effect:
great visuals: http://www.gmi.edu/~drussell/Demos/doppler/doppler.html

here's a make-your-own-doppler wave applet:
http://www.lon-capa.org/~mmp/applist/doppler/d.htm

and some more learnin' stuff:
http://www.glenbrook.k12.il.us/GBSSCI/PHYS/CLASS/waves/u10l3d.html



see video of mach1 flyby: http://www.kettering.edu/~drussell/Demos/doppler/mach1.mpg
read about it here: http://antwrp.gsfc.nasa.gov/apod/ap010221.html

We had a homework assignment that covered our discussion in class, and needs to be turned in before the quiz.