What Objects Can Survive the Deepest Water?

  • Thread starter Rafael Aiguzhinov
  • Start date
  • Tags
    Water
In summary: This means that the gravitational force decreases by a factor of 10 as the pressure increases from 1 atm to 10 atm."This is because the pressure increases the density of the air/water mixture. The higher the pressure, the more collisions there are between molecules, and the more force is exerted on each molecule.
  • #1
Rafael Aiguzhinov
2
2
I wonder, what object can be drown to the deepest water ? I mean, the object where gravity is a lot more bigger than force of Archimedes
 
Physics news on Phys.org
  • #2
Welcome to PhysicsForums. :smile:
Rafael Aiguzhinov said:
I wonder, what object can be drown to the deepest water ? I mean, the object where gravity is a lot more bigger than force of Archimedes
Unfortunately your question didn't translate very well. Are you asking about how a sinking object is affected by stronger gravity as it sinks deeper? If so, I don't think the gravitational force increases with depth, since the gravitational attraction of the mass of the water above the sinking object decreases the net downward force on the object.

Is that what you were asking about, or is your question different? Can you give some examples of what you are thinking about? And is the sinking object compressible or not compressible?
 
  • Like
Likes russ_watters
  • #3
Rafael Aiguzhinov said:
I wonder, what object can be drown to the deepest water ? I mean, the object where gravity is a lot more bigger than force of Archimedes

Anything denser than the densest water in your imagination. If it's the ocean that's not particularly dense and lots of things -- LOTS OF THINGS -- will sink to the bottom.

Being that this is your very first post be prepared for it to sink to the bottom. :-)
 
  • #4
Yes, I meant this
 
  • #5
Rafael Aiguzhinov said:
Yes, I meant this
You mean what? Please give much more detail about your question, or this thread will be closed as substandard.
 
  • #6
berkeman said:
Unfortunately your question didn't translate very well. Are you asking about how a sinking object is affected by stronger gravity as it sinks deeper? If so, I don't think the gravitational force increases with depth, since the gravitational attraction of the mass of the water above the sinking object decreases the net downward force on the object.
If the density of the Earth were uniform and the same as water then the acceleration of gravity would indeed decrease linearly with depth. As you point out, this follows from Newton's spherical shell theorem: The mass of water above the object's depth "does not count" toward the attraction.

Wiki has a nice graph showing how local gravity would scale with depth on:

a. An Earth whose density is uniform.
b. An Earth whose density increases linearly with depth.
c. A model Earth that we believe most closely matches our own.

As one can see from the graph, the real Earth's gravity gets stronger with increasing depth under the ocean's surface. This goes counter to one's untutored expectation.

Both weight and buoyancy ("the force of Archimedes") scale with the local acceleration of gravity. If all other things remain constant, an object that sinks in water at the surface of the ocean where gravity is normal will continue to sink in water at the bottom of the ocean where gravity is slightly higher than that.

Of course, all other things do not remain constant. There are variations in temperature and salinity. There are also pressure effects. Due to increased pressure at great depths, the density of water increases at those depths. This increases buoyancy. But the sinking object is exposed to this same increased pressure. This compresses the object, reducing the buoyant force on the object. Which effect "wins" depends on the compressibility of the object compared to the compressibility of water.

A lump of iron will sink in the deepest water. It will also sink in molten rock. That is essentially the reason why the Earth has an iron core.
 
Last edited:
  • Like
  • Informative
Likes Limebat, Delta2 and berkeman
  • #7
Rafael Aiguzhinov said:
I wonder, what object can be drown to the deepest water ? I mean, the object where gravity is a lot more bigger than force of Archimedes

Ah, maybe my intuition is a tad off, but gravity in simplified classical physics is:
XDZrEDyBodyX5BkqR847VHgvQGaETDTHNPP1e6HZ1pqEzM08u8.png


Assuming we're going as deep sea as possible (Mariana Trench is about ~7 miles) and the Earth is ~3950 miles, the two masses (mass one at sea level and mass two at ~7 miles lowered) are going to have roughly similar accelerations due to gravity.

For reference, the space station at ~422km apogee, experiences ~90 percent of Earth's gravity. So the roughly ~7 mile difference wouldn't really affect much.

However, this formula is a gross oversimplification of gravity. It doesn't account for the stipulations the post above made^. I would highly encourage further study of the stuff the dude above me posted!

A question similar to yours:

https://physics.stackexchange.com/questions/132935/gravity-beneath-sea-level

*I would recommend you look at the last post on bottom of site to see an elaboration on the shell theorem.

On that note, maybe you're thinking deep sea pressures? I mean, it sounds like you are wondering why extreme forces are acting on an object below sea.

If that's the case:

"Your figure for being below water is not correct. As you descend in the ocean the ambient pressure increases by about 1 atm/10 meters. In a uniform sphere, the gravitational field is linear in the radius, zero at the center. Making the incorrect assumption that the Earth is a uniform sphere, being down 1 km would decrease the gravitational acceleration by about 1637116371, not much change."

- The first post in reply to the link I sent
 
  • #8
But the pressure is sufficient to compress the neoprene in your wetsuit. Back in the days before buoyancy compensators were the norm, the 15 lbs of counterweights made you pretty heavy when you got down to 10 meters...dancing off the bottom on flipper tips. Now that was a long time ago!
 

1. What is the deepest point in the ocean?

The deepest point in the ocean is the Challenger Deep, located in the Mariana Trench in the Pacific Ocean. It has a depth of approximately 36,037 feet (10,971 meters).

2. Can any object survive the pressure at the bottom of the Mariana Trench?

Yes, some objects have been found to survive the extreme pressure at the bottom of the Mariana Trench. For example, deep sea creatures such as the Mariana snailfish have been found living at these depths.

3. What materials are best suited for surviving the deep ocean?

Materials that are best suited for surviving the deep ocean are those that can withstand high pressure, extreme cold temperatures, and corrosion from saltwater. Some examples include titanium, ceramics, and certain types of plastics.

4. How do scientists test the survival of objects in the deep ocean?

Scientists can test the survival of objects in the deep ocean by recreating the conditions of the deep ocean in a laboratory setting. This can include subjecting objects to high pressure, cold temperatures, and saltwater exposure to see how they hold up.

5. Are there any man-made objects that have successfully survived the deep ocean?

Yes, there have been several man-made objects that have successfully survived the deep ocean. These include deep sea exploration vehicles, such as the Deepsea Challenger, and oil and gas drilling equipment.

Similar threads

Replies
12
Views
4K
Replies
13
Views
641
Replies
1
Views
926
Replies
46
Views
3K
Replies
6
Views
2K
Replies
9
Views
804
Replies
18
Views
2K
Replies
31
Views
2K
Replies
13
Views
4K
Replies
18
Views
1K
Back
Top