Wednesday, April 13, 2011

Waves on a String

Waves on a String


(tip - copy this into your Word document and the just delete the parts you don't need. Then you will have the questions already in your document).

(Drawings and sketches can be done on paper or in Word using the drawing feature.)


Learning Goals: Students will be able to discuss waves’ properties using common vocabulary
and they will be able to predict the behavior of waves through varying medium and at reflective
endpoints.

Directions:   http://phet.colorado.edu/en/simulation/wave-on-a-string

1. Open Waves on a String, investigate wave behavior using the simulation for a few minutes. As you
look at the waves’ behavior, talk about some reasons the waves might act the way they do.

2. Write a list of characteristics that you will use in this activity to describe the waves. Describe each
characteristic in words that any person could understand. Leave some writing space for characteristics
that you might think of later during the activity.

3. With the Oscillate button on and with No End checked, investigate waves more carefully using the
Amplitude slider. Write answers to the following after your group has talked about each and agreed.
a) Define Amplitude in everyday language.
b) Explain how the wave behaves as the Amplitude changes using the characteristics you described
in #2
c) Use a rope on the floor for some investigations and explain how you could change the
Amplitude of a wave.

4. Repeat step number 3, for Frequency, Tension and Damping.

5. Set Amplitude on high, Frequency, Damping and Tension on low. Also, have on Oscillate, Timer and
No End. Use the Pause button to freeze the wave.
a) Place a blank piece of paper on your monitor and trace the wave and the wave generator.
Mark the green balls. This is a vertical position- horizontal position graph, label your axes.
b) Quickly press Play, and then Pause again. Use the same piece of paper, put it on the monitor
and make sure to get the generator in the same spot. Trace the new wave.
c) Write about the differences and similarities in the characteristics. You may have to do some
more tests by pressing Play, then Pause and tracing to test your ideas.
d) Try some other settings and talk about why I recommended the settings that I did.

6. Set Amplitude on high, Frequency, Damping and Tension on low. Also, have on Oscillate, Timer and
No End. Use the Pause button to freeze the wave.
a) Measure the vertical location of a green ball with a ruler.
B) Record the vertical position and time.
b) Quickly press Play, then Pause repeatedly to make a data table the vertical position of the
green ball versus time.
c) Make a graph of vertical position versus time.
d) Write about the differences and similarities between vertical position- horizontal position
graphs and vertical position-time graphs.

7. Investigate how waves behave when the string end is Fixed and Loose with Manual settings. Discuss
the behavior with your partners. Test your ideas and the write a summary.


Summit all work as a WORD File to dandrade@bridgeportedu.net

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