Music: Sound Waves and Instrument Design
Explore how vibration, pitch, volume, and materials shape musical instruments
Music: Sound Waves and Instrument Design
Explore how vibration, pitch, volume, and materials shape musical instruments
Music - Grade 6-8
- 1
A guitar string vibrates 220 times each second. What is the frequency of the sound wave it produces, and what unit should be used?
Frequency is the number of vibrations each second.
The frequency is 220 hertz. Hertz means vibrations or cycles per second. - 2
Two tuning forks are struck. Fork A vibrates at 256 Hz, and Fork B vibrates at 512 Hz. Which tuning fork produces the higher pitch? Explain why.
Fork B produces the higher pitch because it has the higher frequency. Higher frequency sound waves are heard as higher pitches. - 3
A drum is hit softly, then hit harder. The pitch stays about the same, but the sound becomes louder. What property of the sound wave changed?
Volume is connected to the height of a wave.
The amplitude of the sound wave changed. A larger amplitude makes a sound louder while the frequency can stay about the same. - 4
Look at two sound waves. Wave X has tall peaks and low valleys. Wave Y has short peaks and shallow valleys. If both waves have the same frequency, which wave sounds louder? Explain.
Wave X sounds louder because it has a greater amplitude. Greater amplitude means more energy and a louder sound. - 5
A student shortens the vibrating part of a guitar string by pressing it against a fret. How does this change the pitch, and why?
Think about whether a short string or a long string can move back and forth more quickly.
The pitch becomes higher because a shorter string vibrates faster. Faster vibrations produce a higher frequency. - 6
A string bass has much longer and thicker strings than a violin. Explain how this helps the bass make lower notes.
Longer and thicker strings usually vibrate more slowly than shorter, thinner strings. Slower vibrations create lower frequencies, which are heard as lower notes. - 7
A flute player covers more holes on the flute. This makes the vibrating air column longer. How does the pitch change?
Longer vibrating parts usually make lower sounds.
The pitch becomes lower because a longer air column vibrates more slowly. Slower vibrations produce a lower frequency. - 8
An instrument maker wants a xylophone bar to make a lower note. Should the maker generally make the bar longer or shorter? Explain.
The maker should generally make the bar longer. Longer bars vibrate more slowly, which creates a lower pitch. - 9
A rubber band stretched around a box makes a sound when plucked. When the rubber band is stretched tighter, what happens to the pitch? Explain the science behind your answer.
Compare a loose rubber band to a tight rubber band when it snaps back.
The pitch usually becomes higher because a tighter rubber band vibrates faster. Faster vibration means a higher frequency. - 10
A recorder, a clarinet, and a trumpet can play the same note, but they still sound different. What sound quality helps you tell the instruments apart?
This word describes tone color, not pitch or volume.
The sound quality is called timbre. Timbre describes the tone color that makes different instruments sound unique even when they play the same pitch and loudness. - 11
A student designs a simple drum using a container and a stretched plastic cover. Name two design changes that could affect the drum's sound, and explain how one of them might change the sound.
Two design changes could be changing the tightness of the cover and changing the size of the container. For example, a tighter cover may vibrate faster and make a higher pitched drum sound. - 12
A sound wave has a frequency of 400 Hz. Another sound wave has a frequency of 800 Hz. How do their pitches compare?
Higher frequency means higher pitch.
The 800 Hz sound has the higher pitch. It has twice the frequency of the 400 Hz sound, so it vibrates twice as fast. - 13
In the diagram, Wave A has peaks that are close together. Wave B has peaks that are farther apart. If the waves travel through the same material, which wave has the higher frequency? Explain.
Wave A has the higher frequency because more wave cycles fit into the same amount of space. Closely spaced peaks mean a shorter wavelength and, in the same material, a higher frequency. - 14
A student builds a pan flute using straws of different lengths. Which straw should make the lowest note: the shortest straw or the longest straw? Explain.
This is similar to how a long tube can make a deeper sound than a short tube.
The longest straw should make the lowest note because it has the longest air column. A longer air column vibrates more slowly and produces a lower frequency. - 15
You are designing a new classroom instrument from recycled materials. Describe one part that will vibrate, one way to change its pitch, and one way to make it louder.
One possible design is a rubber band instrument where the rubber band vibrates. The pitch can be changed by using rubber bands of different lengths or tightening them, and the sound can be made louder by plucking harder or using a box as a resonator.