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Wave Speed for Waves on a String

Speed of Waves on a String Lab

Purpose:

In this activity you will be examining the factors that affect the speed of a wave on a string.  This will be an important relationship when we are looking at string musical instruments. 

Info:


Procedure Part 1:  String Density

  1. Open up the program found here.

  2. Go into the tension area and set all the tensions to the same value (equalize them).  Write down the value you are using.

  3. Return to the main area where you can see the entire guitar.  Make a data table listing the six strings, their linear density in g/m, and then have four more columns available.



  4. Click on the hole in the body of the guitar to move to a zoomed in version of the strings.  For each string you will click on its button to send a wave pulse down the string.  Stop the pulse before it is no longer visible.  Record the distance it traveled in cm and the time it took in µs.  Then calculate its speed in m/s.  Finally, convert your linear density into kg/m.

  5. Use the graphing program found here to create a graph of speed vs. linear density (kg/m).  Copy the graph and equation into your lab book.

Part 2:  Tension

  1. Return to the main area of your program.  Change your strings so that they are all of equal linear density.

  2. Go into the tension area and set all the tensions to different values.  Try to get them spread out between 40 N and 100 N.  Make a data table listing the tensions in the six strings and then have three more columns available.

  3. Return to the main area where you can see the entire guitar. 

  4. Click on the strum area.  For each string you will click on its button to send a wave pulse down the string.  Stop the pulse before it is no longer visible.  Record the distance it traveled in cm and the time it took in µs.  Then calculate its speed in m/s.

  5. Use the graphing program found here to create a graph of speed vs. tension.  Copy the graph and equation into your lab book.

Part 3:  Live Part

  1. For this part of the lab you will be using the equipment found up front to look at the connection between wavelength and frequency for a vibrating string.

Things to have in your lab book:

  • Purpose

  • A picture of the lab set up. 

  • Three Data Tables 

  • Three graphs with all the things a good graph should contain.

  • Equations for each graph
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