Lab - Wave Properties in a Spring 11-05
The wave characteristics you will observe in this lab are common to all waves (water, light, sound,
etc.). Use your prior knowledge and the book to fill in the following blanks, then go in the hall and
perform the lab.
A wave is a disturbance that moves through (propagates) through empty space or through a
. There are two types of waves. A wave requires
matter to travel. List some examples of this type:
A wave does not require a medium. Examples include:
In order to start and transmit a mechanical wave, a source of and an
medium are required. A single disturbance is referred to as a
, and a series of disturbances is a wave .
The questions in bold are those you should observe directly. Others will be answered using the book.
A. TYPES OF MECHANICAL WAVES: In the hall, stretch the slinky on the floor until it is
stretched (but still loose). Practice sending single pulses down the slinky by popping your wrist
from the center to the side and back to the center. Then send a continuous wave train along as
your partner holds the other end still. A piece of ribbon should be tied to one coil. Watch the
motion of this ribbon (representing a particle) as the wave travels through the spring.
In this type of wave, the particles move (perpendicular, parallel)
to the direction the wave travels. This type of wave is called a wave.
Its pulses are called and .
Now send a pulse by quickly pushing the spring forward and pulling
it back, as shown. This type of wave is called . Watch the motion of the ribbon.
In this type, the particles move to the direction the wave travels. Its pulses
are called and . Label each.
Note that all waves transfer without transferring . In
mechanical waves, particles of the medium vibrate back and forth in simple harmonic motion while
the disturbance (or ) moves from one place to another.
B. WAVE SPEED
Send a large pulse, followed by a small one. Does one pulse catch up to the other?
(Hint: The person who sends these waves should watch how the waves look when they return. Make
sure that both pulses are large enough initially to make it back to the sender!) The size of the
pulse is called the of the wave. Did the size affect the speed?
Generate a single transverse pulse in the slinky, keeping the stretch constant. Using a stopwatch,
time the journey of the pulse from one end to the other and back again. Take the average of
several trials.
Without changing your positions on the floor (therefore keeping the the pulse
travels the same), pull the slinky tighter using only about 3/4 of the coils. This makes a completely
different medium through which the pulse will travel. Time the journey as before.
Does the kind of medium affect the speed of the pulse?
Lab – Wave Properties in a Spring
PHYSICSFundamentals
© 2004, GPB
11-06
C. WAVELENGTH AND FREQUENCY
Shake the slinky back and forth steadily to send a
transverse wave train while your partner holds the other end still. On the diagram, label wavelength
(- Greek letter lambda). The frequency of the wave depends on how fast you shake the slinky.
Shake it regularly but slowly, then regularly but rapidly.
Higher frequency waves are generated by shaking the spring (slowly, rapidly). High frequency
waves have (short, long) wavelengths, and low frequency waves have .
The speed of a wave in any medium is equal to the of the wave X
. This wave equation shows that f and  are
proportional. Write the units for each of the variables in this equation.