Name: ______
Period: ______Date: ______
Experimenting With Sound
One characteristic of sound is that it is created by vibrations. Sound travels in the form of waves, which have distinct features such as amplitude and frequency. Spend a few minutes at each of the stations located around the classroom to experiment with the sound producing devices. Use this worksheet to record your observations and hypothesis on the factors that influence sound.
STATION A:
Try blowing across the opening of the different bottles and observe how the sound differs between the bottles. Does the bottle with the greatest amount of water produce the highest frequency?
What can you say about the relationship between the amount of water in the bottle and the frequency that is produced?
STATION B:
Pluck the different strings of different lengths and observe the sound that is produced. Notice that all strings are identical in thickness and only differ in length. Does the longest or shortest string produce the highest pitched sound?
How does the length of a string affect the frequency that is produced?
Does the length of the string affect the loudness of the sound that is produced?
STATION C:
Listen to the sounds produced from the Laserdisc and determine what frequencies your ears are sensitive to. What is the lowest frequency that you were able to hear?
What is the highest frequency that you were able to hear?
How does your hearing range compare to the typical hearing range for humans of 20 Hz – 20,000 Hz?
STATION D:
Speak into the microphone of the laptop computer and observe as the frequency and amplitude of your voice are displayed on the screen. Try speaking at different levels of loudness and record how the amplitude is affected.
By looking at the frequencies on the computer, what would you say is the frequency range for human voices?
STATION E:
Carefully whirl the plastic tube in a circle and listen to the sound that is produced. Does the frequency of the tube remain constant?
Does it produce a higher frequency when it is moving towards you or away from you?
Why do you think the frequency changes?
STATION F:
Pluck the strings of identical length and observe the sound that is produced. Notice that all strings are identical in length but vary in thickness. Does the thickest or thinnest string produce the highest pitch sound?
How does the thickness of a string affect the frequency that is produced?
Does the thickness of a string affect the loudness of the sound that is produced?
STATION G:
Stand close to the decibel meter and have your partner record the values from the decibel meter as you speak. What are the values in decibels for a whisper? Normal speech? Loud talking?
Take a few steps away from the decibel meter and repeat speaking at similar levels of loudness. How do the new decibel values compare to the original values?
STATION H:
Use the Data Studio software to first adjust the amplitude, and then the frequency of the sound wave. What happens to the produced sound as the amplitude is increased?
As you move the waves together, what is happening to the sound? Is this creating a higher or lower frequency sound?
DESIGN PROBLEM:
1) The music director at your school has selected you to design a music scale including the eight notes of a scale. You have been given the following materials:
8 Strings of different thickness and identical length as shown below:
Pegboard with hooks of equal spacing (shown below)
Clearly sketch on the pegboard above where you would place each of the eight strings in order to achieve a musical scale. Be sure to remember from your observations how the string thickness and spacing affects frequency.
2) Suppose the strings were identical in thickness but you were able to adjust the spacing between each of the hooks. Sketch the pegboard below showing where you would place the hooks and draw the strings that form the scale. Clearly label the direction in which the frequency is increasing. Label the highest and lowest frequency sides.