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174 Comments
- davidsmero, on 10/12/2007, -15/+341Or sharks with freaking laser beams attached to their heads.
- superbonbon, on 10/12/2007, -6/+226@stephenwq
There are quite a few types of fish that have a tendency to jump out of their fish tanks. I've had personal experience with a few. My best friend had a pair of Oscars that constantly leapt out of their tank onto her carpet. She had to weigh the tank cover down with heavy books and even then they'd bash their heads against it until it knocked down again. We joked that they were suicidal fish.
and a lingering childhood trauma for me...I had fish tank next to my bed and my Dad brought home some new little fish for my tank, I don't know what kind they were but they kept jumping out of the tank as well. They were tiny little fish so I just put a sheet of paper on top of the tank to keep them in. I guess in the middle of the night the paper slid off because I woke up with lots of tiny dead fish smushed in my bed. bleh. - stephenwq, on 10/12/2007, -40/+229@sishgupta: When was the last time you saw a fish which wanted to be out of the water?
- inactive, on 10/12/2007, -12/+138Fish NEED air to live...that's why you see the airators in the tanks. How can it be sealed and get fresh supplies of air?? Weird!
- tonich03, on 10/12/2007, -9/+116Bad ass vacuum.
- tektalk, on 10/12/2007, -8/+112I'm gonna go out on a limb here and say that air pressure acts as a stopper for the water.
- Eldomir, on 10/12/2007, -3/+97Yep, you're right: I'm guessing the top of the tank is airtight. Since air can't go in, water can't get out through the holes, and the tank isn't emptied, so it's really air pressure holding it in.
- doubleyoube, on 10/12/2007, -4/+85thats nonsence dude... Like Eldomir said, the tank is airtight. Its the same effect as when you put your finger over the top end of a straw with liquid in it. The liquid wont run out untill you take your finger off.
- waveman216, on 10/12/2007, -5/+65Chicks should digg me for trying hard...
- smoothmedia, on 10/12/2007, -1/+61Personally, I think this 6 story tall cylinder tank is more amazing.
http://fogonazos.blogspot.com/2007/01/aquadom-worlds-largest-cylindrical.html - Snarfy, on 10/12/2007, -3/+63@ o0|0o
They could pump aerated water through the tank while still leaving it air-tight. - will180, on 10/12/2007, -0/+50In case of fire, break glass.
- diggmeplease, on 10/12/2007, -4/+53http://duggmirror.com/general_sciences/The_worlds_most_amazing_fish_tank_PICTURES
- jonathanbull, on 10/12/2007, -4/+50I dugg you just for trying hard.
- dummersack, on 10/12/2007, -18/+61
- unknamed, on 10/12/2007, -6/+47Uh... maybe, just maybe... they feed them through the freaking holes in the side of the tank? I dunno, maybe that's too obvious.
- dimatt, on 10/12/2007, -4/+37No need to be a jackass lochness.
- screensnot, on 10/12/2007, -2/+35"This is off topic... could someone explain why one can't suck water through a straw longer than 9.81 m."
OK, I'll do my best. (disclaimer: IANAP)
To begin with, you CAN suck water thru a straw higher than 9.81m, under the right conditions. It's also true that different conditions can make the maximum height less than 9.8m.
It's best not to think of it as sucking the water up the straw. What's really happening is that air pressure is pushing the water up the straw.
Without a suction on one end of the straw, air pressure is pushing the water back down equally as much as the air pressure is pushing it up; therefore, the water does not move.
When you add the suction to one end, it removes the air pressure pushing down, allowing the air pressure to push the water up the straw. If you suck hard enough to lower the air pressure to zero (a perfect vacuum), and you are at sea level, the atmosphere is pushing the water up with a pressure of ~1 bar (14.7psi). With the density of pure water, this translates to 9.81m maximum height.
By changing the density of the water, you can adjust the maximum height attainable. Adding alcohol with lower the water's density, allowing you to raise it higher.
And by changing the atmospheric pressure, the maximum height is changed also. Doing the experiment on a mountain (with lower atmospheric pressure) will lower the maximum height. Doing it in a pressurized chamber will raise the max height.
BTW, this is the principal that a barometer works on. - Catchpen, on 10/12/2007, -4/+36Wow this is amazingly similair to the pics I submitted 2 weeks ago http://digg.com/offbeat_news/Impossible_Fish_Tank
- Quakes, on 10/12/2007, -0/+32Four semicolons in one sentence? This is madness!
- spamzor, on 10/12/2007, -8/+37Tip: get a hose and blow air into the tank..... lol
- MOJIRA, on 05/17/2008, -16/+44I would love to just drill a little hole somewhere and what the pressure get screwed. Then those little openings would act like fish cannons!
- YHCIR, on 10/12/2007, -5/+30Another 'Amazing' fish tank...
http://digg.com/design/Awesome_photos_of_aquarium_built_at_home
http://knuttz.net/hosted_pages/Home-Aquarium-20061031 - Hologram0110, on 10/12/2007, -3/+27To answer the question about can't suck through a straw 9.81 m.... Thats obviously not true since there are many hoses which are longer and a straw is just a rigid hose... However If you mean in the vertical direction there is some truth to that. Vaccume don't pull, its just everything else pushes... Atmospheric pressures is about 101 kPa. When rho * A * g * h = P * A (h is height of water column, A is cross sectional area it cancels anyways, and rho is density of water fresh water is about 1000kg/m^3) solving for h yeilds 10.296m meaning if your mouth made a perfect vacume the highest you could drink water at is 10.296m above your cup. (assuming 101 kPa pressure around you) This also assumes water is incompressible
- PlasmaSnk, on 10/12/2007, -0/+21They most likely seal the feeding holes temporarily, or just take out the fish and clean it like that.
- keveStyles, on 10/12/2007, -6/+27reflections indicate this tank (and those inlet holes) are exposed to open air (approx 1 ATM pressure depending on elevation). For air pressure external to the tank to be responsible for keeping the water from escaping through the holes the entire volume of water above the inlets would have to exert pressure less than or equal to 1 ATM through the cross section of the inlets (combined). The fact that the fish can break the surface tension of the water without letting too much water escape indicates that Pwater < P air....That is, if this is the case.
More than likely the volume of water would exceed this pressure if exposed to the downward force of gravity alone. The air pocket at the top of tank is probably evacuated creating a vacuum. The tank can be designed in such a way that the upward force exerted on the water cancels out the excess downward gravitational force of the water creating an equilibrium between Pwater and Pair. - czechman86, on 10/12/2007, -2/+21You have full bitching rights!
- FTLJohnson, on 10/12/2007, -2/+20you didn't use the word amazing in your title....
- chingy1788, on 10/12/2007, -11/+29Lucky there aren't any piranhas in there
- Prefection, on 10/12/2007, -0/+17I imagine the water is pumped out of the tank and aerated in a separate container, and then pumped back in. As for cleaning, that's what sucker fishies are for. Adding fish would be as simple as dumping them in the feeder holes. The most important aspect of the tank would have to be an atmosphere skimmer to remove accumulated bubbles. If bubbles were allowed to build up, they would expand, the displaced water would move into the feeding holes, and eventually "burp" its way out onto the floor. And that would make for some VERY sad fishies indeed.
- eoncire, on 10/12/2007, -2/+19http://www.digg.com/design/How_to_punctuate_a_sentence
- joejoeknows, on 10/12/2007, -0/+16It's holy water
- Blowupologist, on 10/12/2007, -2/+18You mean by surfacing before they open the hatch? Not really.
- callinthelaw69, on 10/12/2007, -4/+19Madness? THIS IS SPARTA!
- MAdaXe42, on 10/12/2007, -0/+14I think he's referring to Moon Pools, and he's correct - moon pools rely on the pressure within being the same as the pressure without - commonly used in underwater habs for entry points.
- Bean945, on 10/12/2007, -5/+17@ puttockc
OKIE DOKIE. - Monkeyhoot, on 10/12/2007, -0/+11I like the airtight top explanation, but then how do they clean the tank, or add and remove fish, water, plants, etc.? If the top is a lid (as every fish tank I've ever seen is) then there would be a layer of air above the water and below the lid, and the water would escape through the feeding holes.
I don't get it. - threemagic, on 10/12/2007, -0/+10I don't think he asked HOW they fed the fish since in the pictures of the tank it clearly shows that. He asked how the water was changed, how the tank was cleaned.. that sort of thing.
- CocoaPuffs23, on 10/12/2007, -0/+9Or maybe the one at the Boston Aquarium? That has an unbelievable amount of fish, sea turtles, sharks, rays, and eels in it. I believe it is three or four stories high.
- charlesroldan, on 10/12/2007, -0/+81) cut a hole in a box...
- screensnot, on 10/12/2007, -1/+8I declare moron. (or a lame attempt at sarcasm)
- rossmcd, on 10/12/2007, -3/+10@nepawoods
not only are you late to the smartass party (stephenwg beat you to the punch), but you're also wrong (see superbonbon's response to stephenwg).
i've maintained a fish tank and have also seen fish jump out (usually when changing the water). i thought it was pretty common knowledge that if the water is too close to the top of the tank, you have to make sure it's properly covered. - dyslexicsUNTIED, on 10/12/2007, -1/+8They do that with a compartment that is sealed from the rest of the sub. it fills with water so they can open the hatch and leave in a diving suit. when they want to come in they seal it and it empties the water from the compartment so they can open the door to the sub.
- sishgupta, on 10/12/2007, -29/+36I'm pretty surprised the fish don't jump out.
I wonder if the owner specifically chose fish that tend not to jump? - mousy, on 10/12/2007, -0/+6All that punctuation, and you forgot the period.
- linksus, on 10/12/2007, -2/+8yup airtights the cuplrit here.
like punching a small hole in a bottle of water with some scissors... it will only come out when the top is opened.
--
They probably clean it by blocking those holes before doing it.
dont forget even if it did empty it would only go as shallow as those holes aswell. so i spose the fish ( remaining in the tank lol ) would still be ok. - rossmcd, on 10/12/2007, -1/+7I like the pictures better in your submission
- shellacked, on 10/12/2007, -2/+8The height that a water column can be lifted is limited by two things: 1) Atmospheric Pressure and 2) The vapor pressure of the liquid you're lifting.
A perfect example is this: imagine trying to drink boiling water through a straw (I know you'd burn your mouth, but just run with it). You suck on the straw but you don't get any water, all you get is water vapor.
Check out this table of the vapor pressure of water as a function of temperature:
http://www.chemistrycoach.com/vapor_pressure_of_water.htm
notice that at 100C (boiling point of water) the vapor pressure is 760 mmHg (atmospheric pressure). When the vapor pressure of the liquid equals / exceeds the air pressure above it, the liquid vaporizes (boils).
Notice that at 20C the vapor pressure of water is 17.5 mmHg. This means that if you drop the pressure below 17.5 mmHg the water will spontaneously boil at room temperature. This may sound amazing, but it's true.
Also remember that atmospheric pressure is NOT constant. It varies with elevation and weather systems (high pressure vs low pressure systems).
So the correct formula for the height of a water column is:
delta_P = (atmospheric pressure) - (liquid vapor pressure)
Height of water column = (delta_P) / (Density * acceleration_of_gravity)
so in the example of drinking boiling water out of a straw, the liquid vapor pressure = atmospheric pressure so delta_P = 0, and the height of the water column you can draw is = 0.
I spent a number of years working on liquid ring vacuum pumps.. the amount of vacuum they can pull is highly dependent of the temperature of the seal water (see vapor pressure as a function of temperature linked above..) - echoforever, on 10/12/2007, -2/+8This is off topic... could someone explain why one can't suck water through a straw longer than 9.81 m.
- greenjohnsmith, on 10/12/2007, -3/+9B/c you can't create enough suction to move that volume of water. No?
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