If a tree falls in a forest. And no one is around to hear it, does it make a sound? Answer!

If a tree falls in a forest and no one is around to hear it, does it make a sound? Philosopher George Berkeley asked this famous question in 1710, and people are still debating it.

Where is the forest located. How is sound defined? What do the words “no one” mean? Three things are needed to make a sound. A vibration, a medium through which the vibration can propagate, and a receiver to measure that a sound was made.

Sounds are waves of high and low air pressure called compression and refraction. The amplitude of the wave determines how loud the sound is. And the frequency of the waves determines the pitch that we hear. These waves of pressure enter our ear canal, which vibrate our eardrum which transfers this vibration to 3 tiny bones in the middle of our ear, which in turn transfer the vibrations to the cochlea. These vibrations result in an electrical signal carried by the auditory nerve to the auditory complex of the temporal lobe of the brain. It is here that the electrical signals are processed, and allows us to hear things.

The frequency of sound that our brains can interpret however is limited to 20Hz to 20kHz. One hertz just means one cycle per second. IS sound only a sound when a person hears it? If no person is around, the sound can still be perceived by animals. Other animals hear sounds using the same mechanism as us. In many cases their hearing is actually more acute than ours. Dogs for instance, can hear sounds more than 45Khz.

What if we take all the animals out of the forest? There are still millions of insects in the forest that can definitely hear sounds. A fly for example, can hears sounds of 50Khz.

What if we take all the creatures from the animal kingdom out of the picture, including all the insects in the forest? But there are other trees. In a 2014 study published in the California Academy of sciences, It was shown that plants can detect and respond to sounds. It’s been theorized that sounds could trigger a response via mechanoreceptors, or fine hairlike structures.

There are also trillions of microscopic life forms like bacteria. In a 2016 study by Shaobin Gu et al, experimental results showed that E. Coli bacteria exposed to sound waves had a faster growth rate compared to the control group. Is this not evidence for a kind of “hearing” of sounds by bacteria?

Let’s take all living things out of the forest. Maybe it is lonely tree in the middle of a desert with no other life forms. When it falls, air is disturbed, and sand is disturbed. A large tree would likely create extremely low frequency sound waves, which can travel very large distances. In fact, sonic waves with a frequency below 20 hz are imperceptible to the human ear. But elephants can hear them over 15 miles away. If the tree was located in a forest in Africa or jungle in Asia, an elephant might hear the sound.

Let’s take all elephants away. Then the sand was disturbed, the air was disturbed. It turns out that if the air is disturbed, the micro disturbance of the air, particularly if there are no structures to absorb the sound, could travel far.

Let's eliminate all living things within a 100 mile radius of the tree. The leaves of the fallen tree will be disturbed. And given what I said above about plants being able to perceive sounds, the tree itself will “hear” its own fall. But let’s go even further and say that this was a dry dead tree in a desert with absolutely no living thing nearby for over a 100 miles radius.

The potential energy of an upright tree was converted to kinetic energy. And this kinetic energy was converted to disturbance in the air and ground, and the sound hitting the ground would propagate through the earth. If the question is interpreted as “did” the tree make a sound vs. “does” the tree make a sound. It definitely did make a sound. But nobody was there at the time to perceive the sound. However, if a scientist is allowed on to the scene and is asked whether the tree made a sound. He would be able to ascertain from examining the changes in the sand, and the tree, that indeed the tree must have fallen, and made a sound.

Let’s make the tree free floating in space with no air and no ground. Since there is no medium such as air or ground to carry the sound, the kind of sound that we humans or animals or living things on earth may recognize did not get made. So, it made no known sounds that we are aware of.
#arvinash
#ifatreefalls
But did it make a different kind of sound? By moving the mass, we have made a change in the gravitational bending of space that surrounds this tree. And we have added kinetic energy to the tree, which also affects space time. If we had sensitive enough instruments, we could detect this difference in the gravitational disturbance made by the tree. This instrument would allow us to “hear” the tree even in space.

[FobbitMike]

Nice job on a deceptive subject. Next video: "If a man makes a statement and his wife is not around to hear it, is he still wrong?"

[wjckhamradio]

Does the refridgarator light really turn off when you close the door?

[dfilion]

I believe the question was "translated to modern language" if a tree falls and there is no player characters around will the "matrix" process the scene or just display the end result and save "computer power". This is how you have to consider the question.

[ArvinAsh]

I want to hear your comments after watching this video. Can you think of a way that sound could absolutely never be made if a tree falls? Challenge me.

[stevenicholson]

As A kid growing up I always hated hearing that question. I will offer my analogy of the question with my own question: Keep in mind that you can't change the parameters of the question itself by saying " No One" as in a person, includes animals. Ok, so.. tree falls, frightens a deer and the dear runs out of the forest and on to a highway. Your driving you car, you hits the deer, deer goes through the windshield and starts kicking your teeth out. At this point, I ask you, do you think the tree made a sound when it fell? I would have loved to had been able to respond to my teacher in that fashion when I was a kid, lol

[senseidiary]

I am just thinking how many tree are falling right now all around the Earth..

[MicMrp]

There is a cause and effect. The tree falls ... the concussion with the ground sends out waves through the air with various frequencies unique to that trees impact. Imagine invisible waves travelling outward from the tree. The "sound" takes place when the uniquely shaped wave STRIKES your eardrum.
You "HEAR" the wave hitting your ear. Without a "hearing apparatus" (like an ear) it would just be waves flying through the air quietly.

[herrsonic]

the falling tree in a forest causes a wave form (vibration) which can be interpreted as a "sound" by an instrument that detects it as a "sound." A deaf person has no such workable instrument, and as such can not experience sound, but if the vibration(s) are forceful enough, he may "feel" such vibrations via his touch senses.

[sang-jinri]

The lesson I get from this video episode is: Every action and thought we take and perceive has the potential to be heard and known by someone or something with intelligence, now, in the past, or in the future or in different time dimensions. There is no such thing as secret. More importantly, every action we take has an impact on this universe (or in another one). Our action does matter even if we think it was done in privacy / secrecy. This video touches me religiously more than scientifically.

[carbon_no]

Lmao! I love the animation at the 9:06! That tree literally “just gave up and quit life!” Haha.

[granddesign]

I thought the main question in this problem would be the observer paradox. If a tree falls in a forest (provided there be no living thing there, including microbes), there would be no observers, and thus the particles of the tree would remain in superposition. If that's true, then how can a sound be emitted? Does that mean that a living observer needs to be around in order for a tree to fall and produce sound? I thought you would've mentioned this in the video, I'm surprised to see you didn't. The answer to that question is, of course, no, there doesn't need to be an observer for a tree to emit sound as it falls. A conscious being doesn't need to be present for an "observation" to happen, the term is wrongly coined. It's the biggest misconception in all of quantum mechanics. Two particles interacting with each other can also cause an "observation". Therefore, all the particles interacting with each other within and around the tree will cause it to snap out of superposition and make a sound. The belief that consciousness is needed for something to exist is called Biocentrism, and I think that it is totally wrong. The Universe can exist without consciousness. If consciousness is needed for something to exist, then how come the Universe was existing for many billions of years, and doing just fine, before we living beings came along? The same is true for the tree, it can do just fine without us humans.

[TheFinalStanza]

it's as simple as asking if someone deaf were near the tree when it falls, does that mean that the fall didn't have any sound associated with it simply because the person was deaf? is the tree gonna ask the person "excuse me can you hear anything? no? alright boys, sound's off this time"

[meandnoother]

The answer to the title: Yes. End of video.

[drewlovelyhell]

I always thought that this was a silly question. Sound is just the word we use to describe a vibration that we can detect wih our ears. Take the ears out of the equation and the vibration still occurs.

[george]

YES . If a tree falls in a forest with no one around,
a cricket, deer, squirrel, some critter will hear
and react to it. We are not alone on this planet people.

[read]

At 1:30 you are already wrong. A sound doesnt need a receiver. A sound wave is a type of energy. It exists whether an animal can hear it or not

[garyfidler]

The answer is yes.. of course it “makes a sound”. The question is not “is the sound heard. That’s like asking, if it rains in a forest, but nobody sees it, does the ground get wet?! That’s a slight exaggeration, but still in the same ball park.

[saggychhetri]

If the tree fell in space and it was made to be perceived that it fell by adding a opposite force even without any medium present the sound must travel within the tree as it itself becomes a medium for sound to travel. Does that sound energy remain in the tree to be detected at a later time is something that needs to be reaearched.

[ldentifiable]

"Scientific method for dummies"?
It could be also based on the "Is there a reflection in the mirror if there is none in the room?" question.

[rippelfamily]

To me, answering this question mostly requires clarifying the terms, such as: what is "sound"? If sound is merely vibration of a medium, then falling trees make sound even when nothing living hears it. If "sound" requires being perceived, then falling trees don't make a sound if nothing living hears it. Doesn't really matter whether the answer is "yes" or "no". What matters is that we know what "yes" or "no" means.