Waves on a String Simulation

Name:______

1.  Go to the following link: http://phet.colorado.edu/en/simulation/wave-on-a-string

Run Now!

2.  For this activity you will be collecting data to explore different wave properties.

For the first set of investigations, we will look at amplitude.

·  you need to be on

·  The rest of your screen should be set up like this:


Look at the table below to see the things that you will be measuring and fill in the table

Amplitude setting / Height of wave at the start
(be sure ruler is lined up correctly) / Distance traveled by pulse (cm) / Pulse travel time (s) / Velocity of the pulse (cm)
100
50
25

Explain the effect that the amplitude had on the speed of the wave. Discuss any similarities and differences in your answers. Explain.

3.  For this next part we will investigate wavelength.

·  You need to be on and DAMPING should be set to 50.

·  The rest of your screen should be set up like we did for number 2.

·  Try out the button after you hit pause. This may be useful for collecting data.


Measure the wavelength at two different points as shown above and record below. Also time the wave to get from one end to the other. Change tensions and repeat 2 more times. Complete the table.

First Second time velocity

Wavelength (cm) Wavelength (cm) (s) (cm/s)

Max tension

1 notch down

2 notches down

Now calculate the frequency of oscillation for each of the three trials.

Compare the frequency of the three trials. Explain the results.

What factor did the damping setting play in the experiment?

4.For the next simulation, we will look at frequency.

·  you need to be on

·  Amplitude should be 50, damping should be 0 and tension is on “high”.

·  Select No END.

·  Remember, to stop or slow the wave use pause/play and .

Move the vertical ruler so that it is along the wave’s path.

This will be the point where you watch waves pass and count them.

Count the waves passing the ruler in 10 seconds. Finish the table.

frequency / Time interval / Number of waves: / Average number of waves counted in 10 second period / Number of waves in 1 second
frequency**
Trial #1 / Trial #2 / Trial #3
50 / 10 seconds
10 / 10 seconds
100 / 10 seconds

*To find frequency, divide the average number of waves counted by the time interval

Describe what happened when you changed the frequency (be careful using words like fast and slow)

5. Use arrows, or draw on the wave, to show what will happen when the amplitude is increased:

6.  Use arrows, or draw on the wave, to show what will happen when the frequency is increased:

A wave is created on this string by moving the wrench up and down.

7.  What would change if the wave had a higher frequency?

8.  What would change if the wave had a higher amplitude?


9. Which picture shows how increasing the frequency in the wave will affect the wavelength?

A.  C.

B.  D.

10. Describe frequency, wavelength, amplitude and period.

1