Interpreting Graphs of Sounds of Different Loudness

Instructor: Mary Beth Burns

Mary Beth has taught 1st, 4th and 5th grade and has a specialist degree in Educational Leadership. She is currently an assistant principal.

You can tell people a lot about the sounds that you hear with your own ears, but can you do the same thing just by looking at a graph? Come and learn how to impress your friends by interpreting graphs of sounds of different loudness in this lesson.

How Does Sound Travel?

Imagine you're playing outside when, all of sudden, you hear the ice cream truck! Those beautiful sounds of the bells playing a song on the ice cream truck are getting louder and louder as the truck begins to approach your house.

Now, try to get your mind off of ice cream and think about this: how were you able to hear the sounds of the ice cream truck?

To answer that, we need to think about how sound travels. When a sound is made, it travels through the air. As it travels, it causes the air particles around it to vibrate. When the vibration reaches your ear, you hear the sound.

Characteristics of Sound

Think of all the different sounds out there: a siren blaring, a baby crying, a bird chirping. Sounds come in a variety of forms. For one thing, they vary in volume, or loudness. Sounds that are loud, like fireworks exploding or a crowd cheering, are high volume. Sounds that are quiet, like a whisper or a cat purring, are low volume.

Sounds also vary in pitch, which measures how high or low the sound is. Sounds like tires screeching or mouse squeaking have a high pitch. Sounds like a tuba or a dog growling have a low pitch.

Noise is another characteristic of sound. Did you know that sounds and noise are two different things? While many people may use these terms interchangeably, a sound refers to a pure note. Noise, on the other hand, refers to anything that you hear that isn't the pure note.

Think of it like this - have you ever listened to FM radio while on a road trip? If so, you might have experienced being able to hear a song on the radio clearly at one point, but then as you travel further away from the radio station, you would begin to hear static. The song is the sound and the static is the noise.

How is Sound Measured?

Sound travels in a vibration, right? Well, what does a vibration actually look like? Basically, it just looks like lines goes back and forth in a zig-zag, wave-like fashion. You can actually learn about what the sound was like just by looking at the graph of the sound.

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