Block waves

Wed/Thurs physics block.
Yeah double physics!!!

We did lots of things in this class.

First, we finished the second slinky lab.
Then we talked about the lab: standing waves, medium determines the speed, etc.

We discussed the terms "node" and "anti-node" and saw the visual of the bugel playing, with a representation of the nodes/anti-nodes (click the "physics" button on the bottom to display)

We saw the video clip of "slinky football", showing different slinky/spring waves traveling across a surface. The interesting part was when one slinky was stretched out, and one was looser, the wave traveled faster in the tight one. Then we looked at three different materials (garden hose, slinky, and brass spring). We saw that each material, stretched that distance, had a different speed.

Next, we looked at water waves in the ripple tank, and examined a "moire" pattern on a small handout (circles on paper and transparency sheet, overlapping).
A few simulations showing this:
http://www.walter-fendt.de/ph11e/interference.htm

http://www.falstad.com/ripple/ (adjust the simulation to "2 sources, 1 frequency")

We listened to this same phenomenon happening with sound waves, pumping an annoying tone through the classroom, out of two speakers. The waves interfered with each other, sometimes making a loud sound, sometimes cancelling out.

We then worked on a homework assignment, drawing wave superposition witih triangle and square waves.
See more wave superposition: http://www.phy.ntnu.edu.tw/ntnujava/viewtopic.php?t=35
and even more: http://www.kettering.edu/~drussell/Demos/superposition/superposition.html

Last, I handed out a homework assignment and talked about the first few problems (car suspension and blinker synchronization). This homework will probably be taken up on Monday.

wave superposition homework should be done-ish by Friday. If you have questions, we can address those and I'll take the work on Monday.

Friday we'll look at standing waves on a string, and more sound/instrument related phenomena.