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no planes and no conveyer belts but.....
what would happen to fish during a rocket launch?
would they get flattened at the bottom of the tank or would they remain floating/swimming at the same level?
flattened, same momentum change as everything around them
Floating. As they are at the same buoyancy as the water, they have the same momentum change as everything around them.
Fish have no plaice on a space mission.
Unless it's just to look at some sort of cod science or something.
they would die surely.... doesn't liquid change consistency in space meaning it would float away and the fish too?
these puns are only just turbot to start and I'm already feeling a bit seasick..
Sink. The fish is neutrally bouyant because of the swim bladder, which is a small gas filled bladder. As the rocket accelerates, the pressure in the water increases and the bladder will shrink. Since it's the volume of the bladder that dictates how bouyant the fish is, as the volume decreases the fish becomes less bouyant.
Those super deep free divers experience the same thing. They have to pull themselves down using the rope at first, but the pressure shrinks their lungs after a certain depth and they start to sink.
Oh.. just had a thought though.. The fish must be able to inflate or deflate its bladder according to its depth, mustn't it? So if it were relatively mild acceleration it would probably actively be able to stay floating.
[quote=molgrips ]
Oh.. just had a thought though.. The fish must be able to inflate or deflate its bladder according to its depth, mustn't it? So if it were relatively mild acceleration it would probably actively be able to stay floating.
That
Oh.. just had a thought though.. The fish must be able to inflate or deflate its bladder according to its depth, mustn't it? So if it were relatively mild acceleration it would probably actively be able to stay floating.
fish do have some control, although considering you can make a cods swim bladder pop by reeling it up to the surface too quickly i think a rocket launch might be considered slightly more than a 'relatively mild acceleration' 😆
Well what's the depth range of typical fish? Pressure goes up pretty quickly as you go down even 10m or so, and the effect of a goldfish bowl's worth of water even under 5g isn't going to be as much.
In fact, since F = mgh the pressure is simply proportional to the depth, and to g which is what's going to change in the rocket's frame of reference. So 5g is like being under 5 times as much water. Well if a goldfish is in a tank at say 6" depth, it'll only be like being less than a meter under water. Well within the range of even a shallow water species I'd have thought. And the rate of change of pressure would be much lower than a quick dart to the bottom of a pond when the heron turns up.
as much as i appreciate your maths, and would be interested in the addition of the average acceleration of a rocket being launched....
i was merely pointing out that a rocket launch isn't mild acceleration 🙂
as for a 'typical fish' without being as straightforward as to describe the physical attributes of the species, there are a lot of different fish out there living in very different conditions and depths...
they took frogs up into space, i've touched the frog pods that used to be in the ISS 😀
Float. Wouldn't the force pushing up on the bottom of the tank be transferred through the water equally?
I can't believe how difficult we're finding this, it's not exactly rocket sci- oh.
And I was pointing out that even significant acceleration would not produce significant pressure in a fish tank, compared to diving to even small depths in open water.
Ooh, ooh, I actually met someone recently that really is sending fish up into space.
He's the head of Japanese research group looking at bone mineral density amongst other things. He told me that the Japanese space agency approached him with a vague idea and that it has actually turned into reality. It was originally planned for sometime in October, launching aboard a Russian Soyuz (sp?) craft which will transport a container (tank?) of fish to the International Space Station.
The experiment is designed to look at the effects of zero gravity on bone mineral density. Funnily enough, he told me that fish are actually the only animals that can feasibly (ethically) be sent into space now (without being permanently restrained the entire time).
Is this a sequel to 'Pigs in Space'?
Found a link. They left on the 23rd.
[url= http://www.msnbc.msn.com/id/49510553/ns/technology_and_science-space/t/soyuz-rocket-sends-us-russian-crew-fish-space-station/ ]Fish in Spaaaaaaaaaace[/url]
they would be pressed against the bottom of the tank.
A quick google search shows up 29.4m/s/s which is approx 3G
The real question is; battered or breaded?
They float!
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A quick google search shows up 29.4m/s/s which is approx 3G
No, it's approx 3g, and that's in addition to the 1g from gravity.
The problem with photos of fish of course is that they may be actively swimming up or down, rather than simply floating or sinking inertly.
Anyway - how are they going to aerate the tank? Those bubbly things won't work properly at all, they'll just create a sort of mad foam.
So if it were relatively mild acceleration
You must accelerate at a certain speed to reach escape velocity so there is no 'mild acceleration'
However they would float.
You must accelerate at a certain speed to reach escape velocity
Not so. Escape velocity is the speed at which a ballistic projectile would need to be launched from Earth's surface to break out of its gravitational pull. You could reach space at 1mph if that's what your rocket did. Just keep going up.
The real question is; battered or breaded?
You can't ask that! What if it was something like trout, and those were the only two options? People would be floundering around for ages, trying to work out which was the least horrid on their scale of taste.
But what would happen if the rocket was on an escalator?
Yes you wouldn't have to reach escape velocity if you wanted to orbit the earth. But you still have to overcome the acceleration due to gravity to leave the earths surface surely?
Just going up at 1mph isn't getting into orbit, it's like the chap in the balloon last week.
We should ask...
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No, it's approx 3g, and that's in addition to the 1g from gravity.
Yeah, the acceleration of the rocket is 3g. However the force exerted by the rocket is equivalent to 4g acceleration to overcome gravitational pull, hence the reduction in thrust as the rocket escapes earths atmosphere and gravitational pull. Any mass connected to the rocket will be exerted to 4g.
But that is buoyancy in a fluid and can only work within a fluid.
The question is if you put a fish on a rocket and fired it into space would it be squashed or continue to float?
Show me a rocket that uses buoyancy to fly.
But you still have to overcome the acceleration due to gravity to leave the earths surface surely?
Only by a tiny amount. And you need to consider forces, because acceleration is as a result of force.
F = ma
So for a 85kg person, you need 85 * 9.81 Newtons of force ie 834N So if your rocket motor provides 835N of force, you'll accelerate upwards, pretty slowly. At 0.011 m/s/s, meaning that after 5 mins of that you'd be going upwards at 3.5m/s or roughly 8mph.
Just going up at 1mph isn't getting into orbit
Define up!
To get into AN orbit around the earth you need to end up moving in an ellipse or a parabola, which will involve some sideways motion. What happens to you (ie if you fall back down, continue into space, swing around one or more times, end up in a stable elliptical orbit, or a nice circular one) depends on how much sideways and how fast you were going up.
Don't you also have to take into account the mass of the rocket.
This thread sums up why I enjoy this forum so much. The science related randmoness of it all doesn't half put a smile on my face. I know, I'm easy pleased.
As you were...
hence the reduction in thrust as the rocket escapes earths atmosphere and gravitational pull.
The gravitational pull doesn't reduce much even when in orbit.
The gravitational pull doesn't reduce much even when in orbit.
No, but if you're taking your goldfish to Mars it will.
EDIT: wrote your instead of you're, pedantry corner.
Is that a deep fried mars to go with the fish?
The gravitational pull doesn't reduce much even when in orbit.
He is right. In orbit, you are falling to Earth same as if you fell out of a window. It's just that you are moving forward so fast that the ground is always falling away from you at the same rate. You are falling around the Earth.
I knew this thread would be a winner 🙂
it was that story about the Russians that got me thinking, I wondered if they'd need little seats for the cosmofish.
personally i reckon they stay where they are butI can't prove it, I'm banned from keeping fish. rockets.... I have a plenty in the underground lair but after the incident with the sharks and the lasers, no more fish!!!
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I don't mean to carp, but this thread started so promisingly and then began to flounder when you got all "scientific"
Just to recap, so are fish unaffected by acceleration because they are floating in a liquid?
If so, why don't they fill fighter pilots cockpits with water (apart from the fact they would drown)?
Observation:
Those fish are all the same way up. Why is that in (next to) zero gravity?
No-one's said they are 'unaffected'.
The pressure in the water increases. And their blood would flow down to their.. er.. belly.. just the same as with fighter pilots.
Why is that in (next to) zero gravity?
It's not an answer, but it's not zero gravity. It's nearly the same as on earth.
The acceleration acts only on the water not on the fish so as long as the fish is neutrally bouyant (or able to maintain bouyancy) then it will feel little in the way of an effect.
Maybe I'm missing something but why look at the effects of weightlessness on fish when they inhabit a zero gravity habitat on earth?
The acceleration acts only on the water not on the fish so as long as the fish
Rubbish.
Maybe I'm missing something but why look at the effects of weightlessness on fish when they inhabit a zero gravity habitat on earth?
Floating is not the same as zero gravity. Take a hot air balloon ride, then pour a glass of champagne, see which way the drink falls.
The water around the fish supports it, but gravity still affects it.
The acceleration acts only on the water not on the fish so as long as the fishRubbish.
Ok - explain this please.
Maybe I'm missing something but why look at the effects of weightlessness on fish when they inhabit a zero gravity habitat on earth?Floating is not the same as zero gravity. Take a hot air balloon ride, then pour a glass of champagne, see which way the drink falls.
The water around the fish supports it, but gravity still affects it.
Not sure what your point is? Of course the chanpagne would fall into the glass gravity still acts on the champagne as air is not a dense medium. The effect of gravity on water pressure is minimal compared to water depth. You cannot compress water so along as the tank that holds the water that holds the fish accelerates at the same speed as the rocket the effect on the fish is tiny. If the fish were forced to the bottom of the tank there is no way they would survive the journey into space let alone swim around to have experiments performed on them.
as air is not a dense medium.
So if it was dense, it would some how be a gravity shield?
The effect of gravity on water pressure is minimal compared to water depth.
so what causes the increase in pressure when you go deeper?
As has been said, gravity is much the same in orbit as it is on earth.
What will happen if an absent minded astronaught knocks over the fish bowl and spills the water and fish into a giant floating orb of water.....will the fish continue to swim around inside the blob?
Do any of the fish know how to drive the tank?
Maybe I'm missing something but why look at the effects of weightlessness on fish when they inhabit a zero gravity habitat on earth?
?
There is still gravity under water. Drop a brick into a pond to check if you wish.
The brick will fall more slowly than it would through air as the drag casued by the water is more than that casued by air but it will still fall. Some stuff which is less dense than water floats in the same way as stuff which is less dense than air floats in air. Helium baloons are not unaffected by gravity, they are just less dense than air and so make their way to the top in the same way that wood is less dense than water and makes it way to the surface of water, wood is not imune to gravity.
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Anyway, back to the OP.
To apply my logic above has anyone looked at what happens to stuff which was in the air inside a spaceship when it takes off? Does all the dust for example make it's way to the back (bottom?) of the rocket or does it remain stationary within the air? Does dust/air serve as a suitable (and observable) analogy for fish/water? It might be a better model is cannot power itself to remain near the top as a fish can.
Dunno, but the Pilot Fish can fly the spacecraft.
Observation:
Those fish are all the same way up. Why is that in (next to) zero gravity?
Id guess the tank is fully sealed with a forced flow from front to back of the tank. Few reasons for that, to maintain a constant flow of oxygenated water for them to breath and ensure there are no 'pockets' of dexoygenated water, to get rid of any fishy 'waste' products, to ensure no big air-bubbles form which the fish could float into and suffocate.
Do any of the fish know how to drive the tank?
^ genius!