1. Wave Motion and Standing Waves Wave pulse traveling down string, striking “fixed” boundary. Wave pulse traveling down string, striking “free” boundary.

2. Take a string, attach one end to an “arm” which can vibrate continuously up and down, and attach the other end to some rigid object. When the vibrating arm moves up, a pulse is sent down the string: vibrating armattach string here

3. pulse travels down string reflects (& inverts) meets another pulse on the way back You end up with standing waves in the string. You may have done this experiment in Physics lab somewhere.

4. L /2 n/2=L

5. Things to note: The wave pulse travels down the string. Does any matter travel down the string? travels down string The matter in the string moves up and then back down, but does not move down the string. As we saw on the previous slide, if both ends of the string are fixed, a standing wave results. If the string is “infinitely” long and the up-and-down pulses repeat, we get a traveling wave.traveling wave

6. The traveling wave moves through the medium. Does any matter move along with the wave? No! The wavelength is defined as before. The period is the time for the wave to travel one wavelength, and f = 1/T as before.