Why is gravity not available under the water ?

Question

When we jump in to the pool we come up without our force Does the water have more force than us ? and When a fish dies it does not go down it floats up . Why is this so ? Doesn't the fish have mass or weight ?

Please give correct naswers becuase I am very confused with this . The impressive answer will get 10 points.

When a stone is carried under water is has less weight why is this so ? and When we get out of the pool we feel a bit heavier than we were in the water . Why is this so ?

Answer 1

A great brain teaser question .

Gravity is there underwater but every thing you say has less dense than water .

So , everything floats . When a drop of water is added to a big jar of oil what happens ? The drop of water goes way to the bottom just because water has more GRAVITY than oil .
Fishes are very light . So are we , We contain air .
Balloons always go up on the water because they contain air.

Anything weighs less in the water . So , you feel heavy when you come out and this is the same principle for a stone(Big ones that is). And when you throw the same stone we talking about, It goes down becuase it is more dense that water . This also means they have more GRAVITY than water .

Water surely has gravity . But the gravity has less strength . Which means water has more dense than its gravity.

Answer 2

Many answers keep mentioning buoyant force, but do no offer and explanation. Here it is:

Say you drop a marble into a glass of water. Because of gravity, the marble will want to go down to the botton of the glass. However, dropping the marble into the liquid, displaced up some of the water. This water that was displaced is also affected by gravity, and because of that, it will also want to go to the botton of the glass - in other words, it wants to displace the marble up. That's called the buoyant force.

How do you know who displaces who? You use the density formula:
M = d*v
Water will always have a density of 1, so
Mwater = Vwater
but the density of the marble can be anything.
The amount of water displaced will always be equal to the volume of the marble. So
Mwater = Vmarble
Mmarble = dmarble*Vmarble
In the end, the one with more mass will end up displacing the one with less mass.
So if the displaced water was heavier than the marble, then the marble would float -that means, the water displaced the marble-
If the marble was heavier than the water, then the marble would sink -that means the marble displaced the water-.

Now you can imagine what would happen if the marble was only slightly heavier than the amount of water displaces: the marble will sink because of gravity, but since it's also fealing the force of the water trying to displace it, it will sink at a very slow rate.

Hope that helped.

Answer 3

Gravity is still at work underwater. Archimedes’ Principle that an object in a liquid is buoyed up (pushed up) by a force equal to the weight of the liquid the object displaces (pushes aside). So, if the weight of the object is less than the weight of the water it displaces, the object will float. With air in your lungs, you will weigh less than the water you displace; therefore you will float. If your lungs were full of water, or you expelled all your air, you would most likely weigh more than the water you displaced; thus you would sink.

For one, fish have a swim bladder which helps them maintain different depths. When the fish dies it no longer has control over the bladder and will float on the surface if sufficient air remains in the organ.

Secondly, after death the body's tissues and immune defenses degrade. Bacteria living in the gut (and from the environment too) enter these tissues and take to feasting on everything in site. Most of these bacteria are *anaerobes* (can't live in the presence of O2). They release gases including CO2, H2, and methane, among others, as they digest fats, proteins, and carbohydrates from the fish. The entrapment of gas in dead tissues can also cause the fish to float on the surface. Note however, that it make take some time for sufficient gas to build up.

Answer 4

Gravity is available in water just as there is gravity everywhere on earth. Water is just more dense than air. When you get into water the water pushes on you with the same force as the weight of the water that is displaced by the volume of your body. This is how boats float. And if your body has about the same density as water (fat people float better...) it will feel as if you are weightless. You aren´t really weigthless of course. It´s just that the water pushes you up with the same force as gravity is trying to pull you down.

Air actually does the same thing. A person does not fly of course because a human weighs more than the volume of air the human displaces but hot air and helium does weigh less. This is how blimps and hot air baloons fly.

When something die they begin to decompose. Decompositions sometimes produce gasses. Gasses trapped in a dead fish will cause it to float. The fish becomes more bouyant.

Answer 5

It is due to buoyancy. buoyancy is the upward force on an object produced by the surrounding fluid (i.e., a liquid or a gas) in which it is fully or partially immersed, due to the pressure difference of the fluid between the top and bottom of the object. Buoyancy acts against the force of gravity and so makes objects seem lighter with respect to gravity. To represent this effect, which is important for sedimentation, it is common to define a buoyant mass mb that represents the effective mass of the object with respect to gravity
m(b) = m(object)[1-{ρ(fluid)/ρ(object)}]

where mobject is the true (vacuum) mass of the object, whereas ρobject and ρfluid are the average densities of the object and the surrounding fluid, respectively. Thus, if the two densities are equal, ρobject = ρfluid, the object appears to be weightless. If the fluid density is greater than the average density of the object, the object floats; if less, the object sinks.

When you jump into the water Archimedes' principle, or the law of upthrust works against the gravity. Archimedes' principle is,

Any body wholly or partially immersed in a fluid experiences an upthrust equal to, but opposite in sense to, the weight of the fluid displaced. ("Fluid" means liquid or gas.)
In other words, when a body is partially or completely immersed in a liquid, then it experiences an upward buoyant force which is equal to the weight of the fluid displaced by the immersed part of the body.

Answer 6

There is a basic misunderstanding in the conception regarding grativation underwater so far its reveals from the question. Let me try to make it clear if I can.

A material which is weighed say as 5 kg may seem somewhat lighter when it is immersed in the water. Why it happens?

When we handle it in air, it is attracted by the gravitation of the earth and it is the air which can make an effect on it to resist the gravitation. But when it is immersed in the water, it is water which makes an effect to resist the gravitation working on it. The resistance made by water in the matter is much higher than the same made by air because water is much heavier than water due to its higher molecular orientation.

Moreover when something is immersed in water, the material replaced its same volume of water and the said replaced water gives upward thrust on the immersed material (Archimedes Principle : Hydrology - Basic Physics : when a body is immersed partly or wholly in a fluid, it is buoyed up with a force equal to the weight of the fluid displaced by the body. ) which makes the buoyancy. Hence the weight of the immersed body loses its weight (virtually) equivalent to the quantum of thrust given by water to it and the same seems to be lighter.

When fishes die, due to rottening of metabolism in it, various gaseous substances grow in it. It behaves like a baloon and the weight of the volume of water replacement by it is greater than its own dead weight. Hence the died fish behaves like a boat as a boat replaces water while floating more than its own weight.

Is it clear now?

Answer 7

There is a property of fluids called buoyancy (Tendency to float) for all fluids.(that includes gases). This is caused by the difference in density bet ween the fluid and the body immersed.

Since all animals including humans are nearly 80% water the density hovers around water density. If the lungs are expanded the density becomes a little less. If lungs are empty, a little more. If the difference in density(between the body and water) is is negative it floats: if positive, it sinks.

In the case of gases, an air filled balloon sinks slowly in air. It floats if filled with helium. It floats up faster if filled with Hydrogen. The same air filled balloon will float in carbon dioxide.

Answer 8

There is gravity under water but it is a weak force and easily offset by buoyancy. Some fish float when dead if their swim bladders are full of gas, which can come from bacterial decay as well as from their filling it before death. Dead things frequently sink but float later from the added buoyancy from decay gases. Gravity is very weak as a force especially in liquid environment, relatively weak in gas environments, but surprisingly there in space as any mass will have some effect on any other. We don't see that in our back yard.

Answer 9

The situation is this:
If you are in water, and gravity causes you to sink, you will sink to the bottom of the pool and there you will be taking up space that would otherwise be taken up by the water. The water you have displaced has to go somewhere else, effectively increasing the water level- AGAINST gravity. So if gravity pushes you down into the water, in doing so it would push the water level UP. Since you have almost the same density as water, the total amount of water that would have to be lifted, weighs practically the same as you do. Since gravity cannot push you down without pushing water up, or push the water down without pushing you up, neither happens, and you feel weightless.

Answer 10

Gravity is present everywhere. When you jump in a pool, you have air in your lungs. this brings you up to the surface. Hadn't it been for this, you would sink. But a dead person floats... This is because his body has absorbed a lot of water, and is now lesser dense than water.
The same happens with fish.