Could a fish swim faster than sound?

  • Context: Undergrad 
  • Thread starter Thread starter haael
  • Start date Start date
  • Tags Tags
    Sound
Click For Summary

Discussion Overview

The discussion explores whether it is possible for fish or birds to swim or fly faster than the speed of sound using only their natural means of propulsion, such as fins or wings, without any external aids like rockets. The conversation touches on theoretical considerations, practical limitations, and specific examples from nature.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Some participants argue that it is not possible for any animal to break the sound barrier without mechanical assistance, citing the speed of sound as comparable to that of a bullet.
  • Others note that the speed of sound is significantly faster in water, approximately 4.5 times faster than in air, which raises questions about the feasibility of swimming at such speeds.
  • A participant mentions that dolphins can swim faster by riding the wake of a ship, suggesting that external factors could allow for higher speeds, though this is conditional on the ship's speed.
  • There is a discussion about the Pistol Shrimp, which can create a cavitation bubble with its claw that travels faster than the speed of sound, although some participants challenge the relevance of this example to the original question of swimming or flying.
  • Some participants express curiosity about the theoretical implications of swimming faster than the speed of sound in a medium, questioning the mechanics of pushing against a fluid at such speeds.

Areas of Agreement / Disagreement

Participants generally disagree on the possibility of animals swimming or flying faster than sound, with multiple competing views presented regarding the conditions under which this might occur.

Contextual Notes

The discussion includes assumptions about the mechanics of swimming and the nature of sound propagation in different mediums, which remain unresolved. There are also references to specific speeds and conditions that may not be universally applicable.

haael
Messages
537
Reaction score
35
Is it possible for a fish or a bird to swim/fly faster than sound? I mean: no rockets, no free fall, no cheating by tying a string to the ground and using it to violate the conservation of momentum.

Is it possible to accelerate over the speed of sound using only fins, wings or screws?
 
Physics news on Phys.org
haael said:
Is it possible for a fish or a bird to swim/fly faster than sound? I mean: no rockets, no free fall, no cheating by tying a string to the ground and using it to violate the conservation of momentum.

Is it possible to accelerate over the speed of sound using only fins, wings or screws?

Not possible, the speed of sound is around the speed a bullet is ejected from a gun.
 
Another thing to consider...the speed of sound is much much faster in water, isn't it?

Edit: looked it up. Approximately 4.5x faster in water.
 
Last edited:
well actually a dolphin can't swim that fast, but put it behind a cruise liner or another ship and they can go pretty darn fast. Faster then they're supposed to, by riding on the wake, as there is less drag due to the ship doing the work for the dolphin. So i wouldn't be surprised if they could do it if they were behind a ship that traveled sufficiently faster than the speed of sound. Assuming, that the terminal velocity of water, like that of air, isn't lower than the speed of sound itself.
 
no there's no animal that can break the sound barrier without attaching rockets to it and that would be pretty cool/cruel. I wonder if we could genetically engineer one some day to do that though, maybe convert food into rocket fuel or instead of flapping wings eject streams of air out the back. I was watching a documentary based on possible animals that could exist on alien planets, they had an animation of a bird firing streams of air behind it to propel itself but I don't think they said it was possible for it to break the sound barrier.
 
Of course it's possible in theory to go faster than the speed of sound under water, but in practice its nowhere near possible for an animal to get going that fast.

Simon Malzard, but then the water would be traveling, so the dolphin would just be inside water which is traveling faster than the speed of sound.
 
Well, this guy wants to break the sound barrier with no motors...

http://dnainfo.com/20100122/manhattan/skydiver-will-attempt-break-speed-of-sound-with-freefall-from-space
 
I think the point of the question is can you theoretically swim faster than the speed of sound in the medium.
If swimming involves pushing against a fluid can you do this faster than a 'push' can travel through the fluid?
 
cstoos said:
Another thing to consider...the speed of sound is much much faster in water, isn't it?

Edit: looked it up. Approximately 4.5x faster in water.

Yes, the molecules are closer together in water, so disturbance travels faster.

Simon Malzard said:
well actually a dolphin can't swim that fast, but put it behind a cruise liner or another ship and they can go pretty darn fast. Faster then they're supposed to, by riding on the wake, as there is less drag due to the ship doing the work for the dolphin. So i wouldn't be surprised if they could do it if they were behind a ship that traveled sufficiently faster than the speed of sound. Assuming, that the terminal velocity of water, like that of air, isn't lower than the speed of sound itself.

The ship would have to be traveling at 720 Knots to surpass the speed of sound.
 
  • #10
Maybe not swim faster than sound, but the 'Pistol Shrimp' can move faster than the speed of sound. Its claw closing travels faster than the speed of sound, taking the local pressure to below the vapour pressure of water, causing a cavitation bubble, which it uses to hunt prey.

Actually, people think this kind of thing could have applications in future fusion technology, the temperatures created as the cavitation bubble collapses are pretty impressive.

Perhaps not what you were looking for, but quite interesting I think.

,Simon
 
  • #11
SimonRoberts said:
Maybe not swim faster than sound, but the 'Pistol Shrimp' can move faster than the speed of sound. Its claw closing travels faster than the speed of sound, taking the local pressure to below the vapour pressure of water, causing a cavitation bubble, which it uses to hunt prey.

Actually, people think this kind of thing could have applications in future fusion technology, the temperatures created as the cavitation bubble collapses are pretty impressive.

Perhaps not what you were looking for, but quite interesting I think.

,Simon

I don't think it moves faster than sound because of this action. The entire mass of the shrimp would need to be accelerated to this velocity and the force of the action is not enough to do this.
 
  • #12
I meant that its claw travels faster than the speed of sound. The cavitation bubble is somewhat similar to a sonic boom in air. The shrimp remains stationary.
 
  • #13
I think the point of the question is can you theoretically swim faster than the speed of sound in the medium.
If swimming involves pushing against a fluid can you do this faster than a 'push' can travel through the fluid?
Yes, that's exactly my point. Does anyone know the answer?
 
  • #14
cstoos said:
Another thing to consider...the speed of sound is much much faster in water, isn't it?

Edit: looked it up. Approximately 4.5x faster in water.


Which must explain why thinks sound different underwater?

I remember what it sound like but it does sound different.

Or maybe it is because you can't hear the low frequencies because they are reflected away?
 

Similar threads

Undergrad Question about Sound Waves: Faster Than Speed of Sound?
  • · Replies 7 ·
Replies
7
Views
2K
Undergrad Focussing on the Treadmill of Veritasium's Blackbird faster than wind
  • · Replies 15 ·
Replies
15
Views
4K
Undergrad Rocket-Powered Dragsters: Faster than Wheel-Driven?
  • · Replies 30 ·
2
Replies
30
Views
5K
High School How Does Blackbird Leverage Wind Power to Move Faster Than the Wind?
  • · Replies 69 ·
3
Replies
69
Views
17K
Undergrad What if the Universe expands faster than the speed of light?
  • · Replies 19 ·
Replies
19
Views
5K
Ionizing Atmosphere on the nose of a rocket, missile or aircraft to reduce drag
  • · Replies 3 ·
Replies
3
Views
4K
Undergrad Fragmentation of a drop in a miscible fluid
  • · Replies 2 ·
Replies
2
Views
1K
Undergrad Traveling at a speed faster than light
  • · Replies 5 ·
Replies
5
Views
2K
Squid swimming in water fluids problem
  • · Replies 3 ·
Replies
3
Views
2K
Undergrad Faster Than Light Particle: Could it Create the Universe?
  • · Replies 3 ·
Replies
3
Views
1K