Standing Waves Activity

Objective

Determine the velocity of a wave in a spring by observing the properties of standing waves created in the spring, specifically the wavelength and frequency of oscillation.

Lab Procedure

1) Measure a length of spring and have one student hold the spring on either end.

2) Have one of the students holding the spring oscillate his end vertically at a frequency which creates a standing wave with 2 nodes and 1 anti-node.

3) Have a third student use a stopwatch to measure the amount of time taken for 10 oscillations in order to determine the frequency.

4) Repeat these steps for 3 different lengths of spring

Data 

Trial 1

Length of spring = 1.2 m, wavelength = 2.4 m
time for 10 oscillations = 4.16 s, frequency = 2.4 hz

Trial 2

Length of spring = 1.4 m, wavelength = 2.8 m
time for 10 oscillations = 4.73 s, frequency = 2.11 hz

Trial 3

Length of spring = 1.6 m, wavelength = 3.2 m
time for 10 oscillations = 6.09 s, frequency = 1.64 hz

Analysis

using the data from the trials we found the velocity of a transverse wave in our spring to be between 5.2 and 5.9 m/s. One problem that we encountered when doing this activity was that when we changed the length of the spring we also adjusted the tension in order to make the amplitude less. However, by adjusting the tension in the spring we unknowingly changed the wave velocity and compromised the experiment. Also, the wavelengths used were too close together to graphically determine the relationship between wavelength and frequency. We could reduce these errors by using a single length of spring and trying to produce different standing waves. This would reduce the tension problems and would widen the range of wavelengths that we could observe in the experiment.