Gizmo: Waves
By Brianne Hogenson
starstarstarstarstar
Last updated about 3 years ago
54 Questions
Observe and measure transverse, longitudinal, and combined waves on a model of spring moved by a hand. Adjust the amplitude and frequency of the hand, and the tension and density of the spring. The speed and power of the waves is reported, and the wavelength and amplitude can be measured.
https://gizmos.explorelearning.com/index.cfm?method=cResource.dspView&ResourceID=1053
Prior Knowledge Questions
Gizmo Warm Up
Ocean swells are an example of waves. In the Waves Gizmo, you will observe wave motion on a model of a spring. The hand can move the spring up and down or back and forth.
To begin, check that the Type of wave is Transverse,
Amplitude is 20.0 cm,
Frequency is 0.75 Hz,
Tension is 3.0 N, and
Density is 1.0 kg/m.
(Note: In this Gizmo, “density” refers to the linear mass density or mass per unit length. It is measured in units of kilograms per meter.)
Click Reset.
Choose the Longitudinal wave
increase the Amplitude to 20.0 cm.
Activity A
Observe: Click Play. Observe the motions of the hand and of the green dot in the middle.
Measure: With the lights on, click Pause. Turn on Show rulers.
Measure: Click Reset. The amplitude of a transverse wave is the maximum distance a point on the wave is displaced, or moved, from its resting position.
Turn off the lights.
Click Play, and then click Pause.
Use the vertical ruler to measure the height of the green trace, showing how far the green dot moved up and down.
Observe:
Click Reset.
Select Lights on
and turn off Show rulers.
Select Longitudinal waves.
Check that the
Amplitude is 10.0 cm,
the Frequency is 1.00 Hz,
and the Tension is 2.0 N.
Set the Density to 1.0 kg/m,
and click Play.
In a longitudinal wave, the motion of the medium is parallel to the direction of the wave. So, each point of the spring moves back and forth as the wave is transmitted from left to right.
Measure:
With the lights on, click Pause.
Turn on Show rulers.
Measure:
Click Reset.
The amplitude of a longitudinal wave is equal to the distance a point on the wave is displaced from its resting position.
Turn off the lights.
Click Play, and then click Pause.
Use the horizontal ruler to measure the width of the green trace.
Calculate:
Click Reset.
Select Transverse waves.
Select Lights on and Show grid
and turn off Show rulers.
Set the Frequency to 0.50 Hz.
A single cycle is the time it takes the hand to
move up, move down,
and then back up to the starting position. (middle)
Click Play, and then click Pause after exactly one cycle. (This may take a few tries.)
Activity B
Experiment: The wavelength and speed of a wave can be influenced by many factors. Adjust the amplitude, frequency, tension, and density as described in the table below. Then report whether this causes the wavelength and wave speed to increase or decrease. Return each variable to its original value after each experiment.
Analyze:
Click Reset.
Set the Frequency to 0.80 Hz,
Tension to 2.0 N,
and Density to 2.0 kg/m.
Click Play, and then click Pause.
Turn on Show rulers.
In general, the wave speed (v) can be calculated from the frequency (f) and wavelength (λ)
using the formula v = f • λ.
Gather data: Click Reset, and turn off Show rulers. The power of a wave is the amount of energy it transmits each second. The power of the wave is displayed below the spring when Play is pressed. Record the wave power for each of the settings to the right.
Measurements in red are what is being changed
Compare: Click Reset.
Select Longitudinal waves.
Set Amplitude to 20.0 cm,
Frequency to 0.60 Hz,
Tension to 2.0 N, and
Density to 1.0 kg/m.
Click Play.
Activity C
Observe: Click Play. Observe the motions of the hand and of the green dot in the middle.
In a combined wave, the motion of the medium is circular. So, each point of the spring moves in a circle as the wave is transmitted from left to right.
Combined waves, such as ocean waves, do not look exactly like transverse waves. In the Gizmo, the troughs are pointy and the crests are rounded. In the ocean, the crests are relatively pointy while the troughs are rounded.
Measure: Click Reset. S
elect Lights on and Show rulers.
Set the Frequency to 1.0 Hz.
Check that the Tension is 2.0 N,
the Density is 1.0 kg/m,
and the Amplitude is 10.0 cm.
Extra Credit