Role of Sound Waves in Designing Musical Instrument of Different Pitches

What You Need to Know

Sound is a type of energy that moves through material and causes it to vibrate. Vibrate means that a material moves back and forth. A sound wave is the pattern in which sound energy travels. Frequency is the number of sound waves in a given time. How high or low a sound seems to be is called pitch. Note refers to a specific pitch.

How Does Sound Work?

Sound is a form of energy, just like electricity and light. Sound energy is produced when molecules vibrate and move in a pattern called sound waves. When sound waves travel through the air to your ears, the waves cause your eardrums to vibrate. The number of sound waves that reach your ears in a given time indicates the frequency. Your brain interprets the frequency of the vibration of your eardrums as a specific sound called pitch. Sounds with a high frequency have a high pitch. In the figure below, the flute produces the sound with the higher pitch.

What Does This Have to Do with Making a Musical Instrument That Can Play Different Pitches?

Musical instruments are designed to produce different pitches. For example, a guitar has different sizes of strings, and the length of each string can be changed to achieve a certain pitch. The high-pitch strings on a guitar are thinner than the low-pitch strings. Because a high-pitch sound is made by fast vibrations, the thinner the string the faster it vibrates, and the higher the pitch of the sound it produces. The length of the strings also affects their sound. The shorter the strings, the faster they vibrate, producing a higher pitch.

With a wind instrument, such as a flute, covering the openings changes the pitch. This changes the length of the vibrating column of air inside the instrument. Percussion instruments, such as drums, produce sound when they are hit. The pitch varies depending on the space inside the instrument.

Fun Fact

When you hold a large seashell next to your ear, you hear ocean sounds. This is because when sounds outside of the shell enter it, the vibrating air causes the air inside the shell to vibrate. The shape of the inside of the shell affects how the air vibrates, which changes the sound. You do not have to have a seashell to hear ocean sounds; a paper cup will also work. But because the cup has a different shape, the sound will be different.

Real-Life Science Challenge

Exposure to loud sounds for a period of time can cause permanent hearing loss. Tinnitus, which is a persistent ringing in the ears, can be caused by loud sounds. Hearing loss among teens and young adults is on the rise due to their exposure to loud music. More research is needed to determine the negative effects of using technology that produces sound through ear buds or headphones, but it is known that using these devices at high volume puts you at risk for hearing loss.

Experiment

Now, start experimenting with making a musical instrument that can play different pitches.

Hints

• Many household items can be turned into musical instruments, such as rubber bands for guitar strings and boxes for drums.
• Select one type of instrument and design the instrument so that it produces different pitches.
• Identify the musical notes for each pitch.

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