I’m sure you’ve heard of this: If a tree falls in a forest, and there’s no one around to hear it, does it make a sound?
I was reminded of this riddle as I investigated the sources of noise pollution in the ocean. After all, as humans who live on land, we hardly venture underwater long enough to understand and be affected by the noise there. As someone living in a modern city, I am also physically distanced from forests, so I thought it would be interesting to discuss this!
To answer this question, we might first need to take a philosophical approach and answer: what do we define sound as?
Scientifically, the falling of the tree would result in energy conversion from the potential energy of the tree to the kinetic energy of the moving tree, and this would be converted into sound energy (Ash, 2020). In my introductory post, I introduced noise as unwanted sound, sound being energy transferred through vibrations. Indeed, these vibrations produce sound, and our ears detect these vibrations. However, sound could also be defined as what we hear, or rather, what our brain perceives (Bobrowsky, n.d.).
Hence, if we perceive sound to be merely vibrations, then yes. The falling tree would make a sound! However, if we define sound to be what we hear, then being a distance away from the forest, the answer to this question is no.
Watching the video above also prompted me to think about this: who is this “no one” in the question? Does this “one” refer to just human beings? As we know, other creatures on earth can also perceive sound. For instance, flies can hear up to 50,000 Hz (Ash, 2020). Researchers have also discovered that plants detect and respond to sounds (Ash, 2020). If we were to explore the underwater realm, some animals, communicate via echolocation to navigate, find mates, communicate with one another, and evade predators (WWF, 2017). It is evident that animals are also able to perceive sounds.
In that case, we might answer yes to this question, as we can assume that a forest would be filled with creatures or plants at least, that would be able to detect sound (vibrations) that arise from the falling tree, and hear this sound due to their proximity. Whether that one is a human being, remains uncertain.
References
Ash, A. (2020). If a tree falls in a forest. And no one is around to hear it, does it make a sound? Answer! [online] www.youtube.com. Available at: https://www.youtube.com/watch?v=SmoxJFdoHJ4&t=590s&ab_channel=ArvinAsh [Accessed 25 Feb. 2022].
Bobrowsky, M. (n.d.). Q: If a tree falls in a forest, and there’s no one around to hear it, does it make a sound? | NSTA. [online] www.nsta.org. Available at: https://www.nsta.org/q-if-tree-falls-forest-and-theres-no-one-around-hear-it-does-it-make-sound.
World Wildlife Fund (2017). Infographic: Underwater noise. [online] Arcticwwf.org. Available at: https://arcticwwf.org/newsroom/the-circle/underwater-noise/infographic/.