If you love sound and experimenting with recording as much as we do, then you have probably thought about sound in many forms too. Knowing how sound acts can improve your recording and the intensity of sound. That is why we will look at sound and where it travels fastest. You can do some really interesting things when you know and can control how sound reacts to certain environments.
Today we will look at the different mediums and where sound will travel fastest, why sound travels faster in denser materials (solids), and how other factors can influence that.
Why I Wanted to Know
Just like for many of you, sound was fascinating to me. I loved doing experiments that showed how sound changed in different mediums, like when you went swimming, or in other settings. I also loved playing with a tin telephone with my siblings.
That is when you pit a tin on two sides of a string. And even when you only whisper, you are still able to hear the other person on the end of the line. To me, this was one of the coolest things that I had ever heard. I wanted to know why it worked that way. Now I know that solid objects can be a great conductor of sound and that is why it works.
This was one of the first experiments that I ever did with sound, but it would not be the last. My love affair with sound has lasted my entire life and it is still a subject that fascinates me.
Finding out where sound travels fastest is not just interesting but it can also be really useful.
Consideration When Determining Where Sound Travels Fastest
Finding out where sound travels fastest all comes down to one thing: density. Sound needs molecules, the vibrations bump into one and then the sound wave will be carried from one molecule to another. When it bumps into the next molecule it travels farther.
That means that sound can travel faster when the medium that it is being carried in is more densely packed. The denser the molecules in a medium, the faster sound will travel. In the end, denser materials will then conduct sound faster.
There are a few different mediums that are available in the world and also around us. These include gasses, liquids and fluids, and even the void of space. Let’s discuss each one separately and then discuss where sound will travel fastest.
In A Vacuum of Space
We all know that we can see the light of stars that are incredibly far away shining through the night sky. This light travels billions of miles to appear before us. Some of the stars we see don’t even exist anymore since they died out years ago.
It is kind of mind-blowing and amazing. But at the same time, we never hear any explosions from the sun or other stars. We don’t hear the noise of asteroids hitting different planets or any other noise from space. Why is that?
Because, unlike the speed of light, sound does not travel through a vacuum. It might seem like we are surrounded by nothing here on earth. But looks can be deceiving and in reality, we have our atmosphere that is made up of different gasses surrounding the earth.
Outside of the earth’s atmosphere, there is a whole lot of nothing. Space has no atmosphere, which is why we can’t breathe there, and also why we hear no sounds coming from outer space. There are no molecules to carry the sound further. Sound can’t travel in a void.
We know for sure that sound does not travel fastest in space since it can not exist in an empty void.
This brings us to the next medium on the list. Gasses. As we have already mentioned, our earth and all the air we have surrounding us are made up of gasses. You can’t see them with the naked eye, but they are always there.
And we do know that these gasses do have enough molecules for sound to travel through. How do we know this? Because we can hear each other when we speak. We can hear a whisper, birds singing, cars driving down the road and many other interesting sounds that create a soundtrack to the world we live in.
What Are the Gasses in Our Atmosphere?
The atmosphere surrounding the earth is made of 78% Nitrogen and 21% Oxygen. The last percentage of gasses that make up the atmosphere is a mixture of carbon dioxide, neon, and hydrogen. These are not dense materials, and that is why they can exist without us even seeing them.
Sound starts when it is created by vibration, for example when our vocal cords move and produce sound. Then this vibration is carried on the different molecules towards other points, like the person you are speaking to.
We might not be able to see the gasses but the molecules are still able to catch those vibrations, bump into each other and then transfer them until what we are saying can be heard by the next person.
How Sound Reacts in Gasses
In most cases, the speed that sound travels in gasses is a lot slower than in any other medium. The molecules just aren’t packed densely enough to quickly move sound from one spot to another. That is why sound often gets lost over big areas.
For example, if you are addressing a big crowd or people who are spread out over a large open area, you have almost no chance of being heard right to the back by only speaking. Shouting creates a bigger vibration and it is possible that the momentum could allow a shout to travel further than a normal spoken sentence.
But in the end, the best solutions are using tools that will enhance the vibration and allow you to be heard everywhere. Some of these solutions could be a loudspeaker or even a microphone that takes your voice to different speakers. In that way, the sound will be enhanced and the noise will come from different directions. Ensuring that everyone can hear what you are saying.
Things That Influence Sound in Gasses
There are a few things that can influence the speed of sound in gasses. But the biggest factor would be the temperature of the air and the molecules inside it. When it is cold the molecules move around faster. This uses up the energy behind the vibration quicker and the sound can become quieter faster than it would at a higher temperature.
You will need to make a bigger vibration just to be heard from the same distance when it becomes a lot colder. Knowing factors like this will allow you to adapt your sound according to circumstances.
Conclusion On Gasses (Slowest)
We are grateful that we are surrounded by gasses that allow us to hear all the noises that are created around us. But gasses will have the slowest speed of sound and we need to keep searching for the medium where sound will travel fastest.
Next up is liquids. In liquid form, molecules are packed a lot closer than they are in gas form. That is why liquid can get us wet and we can see it. Still, they are still fluid and able to move and that means that there are some spaces between the molecules in liquids. This can impact the speed that sound travels. Sound travels faster in water than it does in gasses. In theory, sounds can travel longer distances and be louder in water than it is in gas. Is this how you experience it?
Why Sound Reacts Differently in Water
When we are under the water, we don’t hear that many sounds. Or they can be muffled. There are a few reasons for this. Sound does not react differently in water than it does in air. Even if it is not how we perceive it, sound does really travel faster in liquids than it does in gasses.
The only real difference is our adaptability. We aren’t adapted for living and hearing noises under the water. Our ears have a route by which we hear. The sound goes through our ears and then it gets interpreted by our mind.
We can figure out exactly where sound is coming from, the source of the sound, what it is, and a lot more just by what we are hearing. But when we are listening while being submerged inside a liquid, like in a swimming pool or the ocean, we don’t have those same capabilities.
Instead, we need to adapt the way we listen when we are in the water. When it is only your ears that are under the water, you can hear even less than when you are fully submerged. Being completely under the water actually helps us to hear better.
This is because our head is full of fluids. When we are fully in water it is our tissue that picks up the different sounds around us. But since we hear it from basically all around us, it is much harder to pinpoint the source and direction of the noise.
Our ears aren’t working as they were designed to, and that is why everything is muffled. Even though sounds are really louder and move faster in water. The intensity of sound can seem less than it actually is.
Sound also doesn’t often breach the surface of the water. Something that makes a massive noise inside the water won’t often be heard on top of the surface. That is because the surface of the water creates a natural barrier and noise will reflect back into the water instead of breaching out into the air.
That is probably a great thing. I don’t know how many of us would be comfortable traveling on the ocean by boat or ship if we kept hearing all noises being made by the huge animals that live inside the sea. I for one would not sleep very soundly with different noises floating up from the ocean depths.
Other Noise in the Ocean
Speaking of animals that live in the ocean, they are adept at listening to noise while being submerged and they can make complete use of the quick speed that sound travels in liquids. Animals like whales can speak to different families that are miles away from them.
Humans have also found ways of using this sound, by using equipment that can pick up noise inside the ocean. In that way, they have been able to study sea creatures a lot closer without going into their space.
Conclusion On Liquids (Faster)
We might not be able to experience it firsthand in most cases. But sound does travel faster in liquids than it does in gasses.
This means that sound can be heard from much greater distances when it is traveling through liquids. It also takes smaller vibrations to create bigger sounds and that is why sound might also be a lot louder in liquids than in gasses.
If our family stays a few blocks from us, we still need a device, like a phone, to carry our sound to them and to speak to them. But animals in the ocean can communicate over many miles without ever needing any other sound enhancement.
Still, molecules In liquids aren’t packed densely, there is still a lot of space between these building blocks. There must be another medium that will allow sound to travel even faster.
Finally, we get to solids. A solid object is something we can touch. This is because the molecules of a solid object are tightly packed creating a dense atmosphere that we can use in many different ways. There are many different materials that solids are made from, and they have different densities.
But overall solid objects have dense molecules and that makes this medium the one where sound travel the fastest.
But this might seem strange. When you speak in a space that is packed with furniture, your voice can become muffled. When you speak in a room with no furniture your voice can even echo. Why is that? How does this make sense along with the fact that sound travels fastest in solids? Which materials are the best conductors for sound? We will find out shortly.
How Sound Travels in Solids
There is no disputing that sound travels much faster in solids than in any other materials. When you bang against a wall the bang will be heard very clearly on the other side. Especially if you place your face against the wall and listen with your ear to the solid object.
That is why solid objects are often used to enhance sound and make it louder. But it is also true that solid objects can stop sound from getting through clearly. If you speak to a person in another room and the door is closed, you won’t be able to hear them more clearly than you would if they were standing right next to you, would you?
Obviously not. It seems like the sound in that case did not travel through solids as well as it would have through a gas. This once again comes down to the way that sound is generated.
When sound is made by speaking or another way of making vibrations and it starts out traveling through gasses, like the air, then the vibrations will be going at a certain speed. The molecules bump into each other and they keep moving the sound forward.
But then this vibration encounters a different medium or object, like a door or another solid surface. The vibration gets interrupted. It has to change the way that it is moving from molecule to molecule and that leads to some of the energy behind the vibration being lost. Each time it encounters this difference it loses some of the energy and in turn some of the quality and volume of the original noise that was being generated.
That is why in many cases soundproofing is made from different layers of materials that are densely packed. Each time the noise hits another layer of the soundproofing it loses some of the energy and gets a lot quieter.
This all changes when a sound starts out inside a solid. When the sound originates from a solid like in the case of banging on a wall, the sound only travels through the solid, there is no disruption and the speed at which it travels will remain high and in turn, it will become a lot louder.
Materials Conducting Sound
As we have found, a medium that has densely packed molecules will carry sound much faster than others where the molecules are further apart. That is why sound travels a lot faster in a solid object than it does in a gas.
But solid objects also have a wide range of densities and not all materials will allow sound to travel at the same speed as others will. Soft solids like cloths, paper, and other pliable solid materials are more likely to just absorb sounds than to amplify them.
On the other hand, harder materials where the molecules are more densely packed will give sound the ability to travel a lot faster. Many musical instruments are made out of harder substances. This is because they not only allow sound to travel faster but also enhance the sound that is produced. It gives off a bigger vibration and that means a louder noise.
Of course, in musical instruments, the volume and speed of the sound would not be the only consideration. We also want materials that will produce beautiful sounds and not just noise. Different materials produce different types of noise and combined they can make some beautiful music. Sound quality is important.
Going back to the speed of sound, sound will be carried best by some hard materials including metals and even diamonds. These are dense enough to allow the vibration to quickly move from one molecule to another without being interrupted by the space between the molecules.
There are two materials that have some of the highest speeds of sound among any other solids. These are aluminum and in second place copper. In aluminum, sound will travel at 6,320 meters per second.
In copper, sound will travel at around 4,600 meters per second. That is fast too. Both of these materials are hard substances but they are also good conductors for sound since they do allow for vibrations that can impact the sound.
Conclusion For Sound in Solids (Fastest)
It is clear that sound travels at the fastest speed in solid objects but not all solid materials are equal when it comes to the speed of sound. Still, if you want to create a lot of noise that will be able to travel great distances, then solid objects are the best option to use.
Where Sound Travels Fastest?
We are surrounded by different mediums and materials that can influence the speed of sound. Sound is created through a vibration that will move from one molecule to the next. When molecules are far apart the sound can’t move as quickly as when they are densely packed.
Since there are no molecules in an empty void-like space, sound can’t exist there at all. In gasses like the earth’s atmosphere, sound will travel but at a much slower rate than in other mediums. Sound travels faster in liquids but because we are not adapted to listening to sound underwater, we can’t easily make use of this fact, but animals can.
Then there are solid materials. Sound travels the fastest in solids than in any other medium and harder materials are even better conductors of sound than softer solid materials. So, sound travels the fastest in materials like aluminum.
But in the end, sound can be interrupted when it goes from one medium to another and that is why sound gets muffled through a door. What we know about sound has allowed humans to create musical instruments that can make loud and beautiful noises that combine wonderfully to make music. Aren’t you glad we have sound?