Last updated: January 4, 2022 at 9:56 am
If you live in the suburbs, you may have found yourself hearing your neighbour or a tower of a nearby stadium calling out the result of a game. Or maybe you’ve tried to talk over someone because they were too loud. But how does sound carry that far? Why is it so loud for one thing and not for another?
This is your chance to learn how sounds can travel so far. For us to understand how sound travels, we first need to know what it is. It’s important to understand this to have a good grasp of soundproofing.
IN THIS ARTICLE
What is Sound?
Sound is a wave of pressure that travels through the air.
Sound is created by vibrations. Any object that vibrates causes sound. A vibration can be caused by something hitting or scraping against a surface, such as the strings on a guitar being plucked or a stick being dragged across a picket fence.
Sound waves will travel in all directions unless something stops them. The waves can be stopped by things that aren’t very dense, like air, water, and wood. If there are no particles to stop the waves, then they will keep going until they reach something that can stop them (like our ears).
Now, when we see something or touch something, we perceive it as being still. That’s because our sense of touch is so limited. But if you were able to feel everything around you, from the ground beneath your feet to the ceiling above your head, you’d feel that everything is actually in constant motion.
Tiny vibrations are constantly shaking and moving everything around us. Our bodies are vibrating too.
That’s where the sound comes from. When something vibrates quickly and repeatedly, it creates pressure waves. And when those pressure waves reach our ears, we hear them as sounds. The quicker they vibrate, the higher the pitch of the sound they make, and vice versa.
The most important thing to remember about sound is that it travels in waves – not straight lines! This can be hard to imagine because most of us don’t experience much three-dimensional movement on a day-to-day basis. For example, when we talk to someone on a mobile or listen to a voice on an answering machine message, we don’t think of their voice as coming from all around us – we just think of it as being in one place.
How Does It Travel?
Sound moves as a wave through the air in much the same way that water moves as waves through the ocean. If you put your hand in front of your mouth and say “ahh”, you can feel the breeze created by the sound. This is because sound travels at about 330 feet (100 meters) per second, and when it gets to your hand, it pushes the air molecules around it.
Tall buildings and hills can stop sound from traveling because they don’t have large amounts of air to move around. That’s why you can’t hear someone talking on an iPhone when you’re in a big elevator or on top of a tall building. The sound just isn’t moving through enough air to get to your ear.
The Speed of Sound Traveling
People often ask about the speed of sound. The answers can vary widely, depending on how you define speed, but here is a clear explanation: The speed of sound depends on the material it travels through. Air, for example, has a different speed than water or steel, or glass.
Traveling through the air at temperatures of 0 degrees Celsius (32 F), the speed of sound is 340 m/s (1125 ft/s). This means that if you see an explosion take place right across from you, you will hear it 1 second after it happened because of the distance being travelled by the sound waves.
At room temperature and normal atmospheric pressure, sound travels at 344 m/s (1134 ft/s). At sea level, this is approximately 761 miles per hour. Because the temperature and pressure change with altitude in the atmosphere, speed will vary as well. For instance, at an altitude of 5000 meters (16400 ft), the speed is approximately 331 m/s (1115 ft/s).
Additionally, the speed of sound depends on how warm the air is that it’s moving through. The warmer the air is, like in summer, the faster sound moves through it.
What Does Sound Travel Through?
Sound travels through air, water, and solid objects. You can hear someone talking through a wall because sound waves travel from the person’s mouth to your ear. Sound waves travel through solids by vibrating the molecules in the object. The vibrations cause molecules to bump into each other, which makes a wave that moves from one molecule to another.
As long as the molecules are touching each other, they stay in contact with each other, sending the wave along until it hits an end of the material or is absorbed into another material.
Sound doesn’t travel through a vacuum, so if you’re in outer space, you can’t hear anything unless something creates a sound wave. If you were floating in space near a rocket blast, you wouldn’t hear it because there isn’t any air for the sound waves to travel through.
Did you know: Dolphins have echolocation which allows them to hunt and find their food at night. They make noises and listen for the echo to bounce back so they can figure out where their food is. They can even tell if there is a big fish or small fish in front of them because they hear different echoes.
What Makes Sound Travel Farther Than Another?
How far away from people a sound can travel based on how big its source is, how hard it hits a surface and what kind of material comes in between the source and your ears.
The Size of the Source of Sound and Its Shape
First, the size of the source of the sound. If you clap your hands, they may create a small or large sonic boom in the air. This depends on how large your hands are.
Also, the shape of your hands determines the size of the sound wave. The larger the object that is producing a sound and the more round (not sharp) its edges are, the farther and louder it will be.
For example, when you blow across the top of a bottle, you hear a high-pitched noise; when you blow across a whistle’s mouthpiece, you hear a lower tone because it changes in shape when you blow it.
A third factor to consider is if you are in an area with many hills or valleys around it. A flat area is perfect for producing sounds because there is nothing to get in their way. Hills and valleys might stop sound from going as far as it could have gone if there were no barriers to block their path.
The Surface That the Sound Is Hitting
Sound travels differently depending on the type of surface it’s hitting and if it’s a hard or soft surface. Sound waves travel faster through hard surfaces than soft surfaces. For example, sound travels four times faster through steel than through air. Sound will also be reflected more easily off of a hard surface than a soft surface. Therefore, you can hear someone talking through a wall, but you can’t hear them when they’re talking behind you.
If sound hits two surfaces at once, the sound that travels the fastest will go straight, and the slower sound will be reflected. This helps explain why you can hear sounds from your neighbour’s house, but not from inside the house next door.
You may have heard the saying that “the squeaky wheel gets the grease”. This stems from the fact that humans hear high-pitched sounds better than low-pitched ones. That’s because high-pitched sounds are spread out over a larger distance than low-pitched sounds, so they have to travel a smaller distance to reach your ear.
When two people are talking, for instance, you can tell what someone is saying based on how far away they are from you – even if you can’t understand them very well.
The Material That the Source Is Made up Of
The source of the sound is important. Something made of a material that vibrates easily, like wood or metal, will transmit sound farther than something like thick glass or rubber that doesn’t vibrate as well. It’s the same reason why a metal drum sounds louder than an identical plastic drum.
Additionally, a big part of how far the sound will travel depends on what’s around it. If you’re sitting in a small room with lots of hard surfaces, like a kitchen with tile walls and floors, then a sound can bounce off those surfaces and make noise even if you’re not talking loudly.
On the other hand, if you’re talking in a large field where there are lots of plants or trees around you, it can be harder for sound waves to bounce off walls or get absorbed by leaves.
Bonus: How does sound bend around corners?
Sound bends around corners not because it “follows the walls” but because it reflects from them. When a wave moves into a new medium, it changes its speed. If the change is big enough, the wave will change direction too. Just like light does when it hits a prism or water does when it runs into an obstacle.
The angle at which sound hits a surface and how hard it hits that surface determine how much the sound is going to bend. The same principles apply to light and water, and for the same reason: all three waves are really just vibrations of atoms. If you want to know what’s happening right now at any point in your room, you don’t have to go there; if you can see or hear there, you can figure out what’s happening.
Final Thought
In conclusion, the speed of sound depends on air temperature, the medium, air pressure, and humidity. As temperature and humidity rise, air molecules move faster. This causes the waves to travel faster through them.
The speed of sound is slower in denser mediums like water and stone and faster in less dense mediums like air and helium.
