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Q: Ocean salt water and density of a boat ( Answered,   3 Comments )
Subject: Ocean salt water and density of a boat
Category: Science > Physics
Asked by: kingkyle1179-ga
List Price: $10.00
Posted: 22 Nov 2004 14:22 PST
Expires: 22 Dec 2004 14:22 PST
Question ID: 432521
Why is there so much salt in the ocean?
Where does it come from?
Why does a ship float better in salt water than in fresh water?
How does a ship float if it is made of steele?
Subject: Re: Ocean salt water and density of a boat
Answered By: tutuzdad-ga on 22 Nov 2004 17:52 PST
Dear kingkyle1179-ga;

Thank you for allowing me an opportunity to answer your interesting question.

?Why is there so much salt in the ocean? Where does it come from??

Both of these questions can be answered at the same time, because the
reason why the ocean is so salty is relative to where the salt comes
from. Salt found in the ocean is actually a result of erosion. Salt is
a natural part of the earth?s crust and there happens to be so much of
it that it accumulates in our oceans. Rain water has somewhat of an
acidic affect upon the dry land. It erodes the land and rocks and what
is left is minerals such as salt. This salt washes toward the lowest
places when happens to be our oceans. Here the salt accumulates and
since it does not break down it makes the ocean salty. Shifting tides
in the oceans also contribute to this kind of erosion on the sea
floor. Salt is eroded from the earth beneath the sea and this too adds
to the salinity of the ocean waters. If all the salt in the sea could
be removed and spread evenly over the Earth's land surface it would
form a layer more than 500 feet thick, about the height of a 40-story
office building.

?Why is the Ocean Salty??

?Why does a ship float better in salt water than in fresh water??

Salt changes the density of water. Fresh water is not nearly as dense
as salt water because the salts dissolved in the water make it
?thicker? than pure water. Objects float better in water that is dense
and since the way things float is dependent upon how dense the fluid
is, things float better in salty water. Imagine how a small slice of
fruit might float better in your oatmeal than in a bowl of tap water.
This is the same basic principle that allows things to float better in


Here is a little experiment you can do at home to see how things float
better in saltwater than in pure water.


?How does a ship float if it is made of steel??

To understand what makes a heavy steel ship float, you have to think
of ?floating? as the point at which an object stops ?sinking?. An
object floats on water because it displaces ? or takes the place of ?
the amount of water equal to it?s own weight. The more water the ship
displaces the bore ?boyant?, or floatable, it becomes. A ship (or
anything else that floats) sinks into the water until it has displaced
its own weight of water, then it will not sink any further. If a ship
weighing 100 tons is placed in the water, it will move aside up to,
but no more than 100 tons of water. Because a ship is a lot like an
empty bowl ? relatively thin steel on the outside and nothing but air
on the inside ? its actual density is less than that of the water it
displaces. So, a 100 ton ship will not displace so much water that it
goes down into the water below the sides of the boat. This causes the
ship to float on the water. This explains why a solid block of steel
will sink and a hollow bowl of steel that weighs the same will not.

?Why can boats made of steel float on water when a bar of steel sinks??

Below you will find that I have carefully defined my search strategy
for you in the event that you need to search for more information. By
following the same type of searches that I did you may be able to
enhance the research I have provided even further. I hope you find
that my research exceeds your expectations. If you have any questions
about my research please post a clarification request prior to rating
the answer. Otherwise, I welcome your rating and your final comments
and I look forward to working with you again in the near future. Thank
you for bringing your question to us.

Best regards;
Tutuzdad ? Google Answers Researcher


Defined above



Google ://









Subject: Re: Ocean salt water and density of a boat
From: guzzi-ga on 22 Nov 2004 18:23 PST
A Researcher answered before I posted but I?ll send it anyway.

Salt dissolves out of rocks by rivers and ends up in the sea. Sea
evaporates, raining on land dissolves more salt....... In enclosed
lakes, with no exit other than evaporation, salt builds up to
saturated solution and can eventually crust over. The reason that salt
(NaCl) predominates is because it is very common, dissolves well and
doesn?t get taken up by marine organisms to be converted into
insoluble compounds. Another factor is that the solubility of salt is
almost constant with temperature so it doesn?t precipitate out. The
solubility of most compounds goes up quite markedly with temperature
(though a few go down). There are actually a lot of other ?salts? in
the sea, but much lower concentrations.

Ship float ?better? in salt water because the water is more dense so
the ship floats higher in the water. One of the easiest places to swim
is The Dead Sea (landlocked) because you almost bob on the surface. A
beautiful illustration is that solid lead floats happily on mercury
because even lead is much less dense (lighter) than mercury.

A steel ship floats on water because it?s not made of solid steel,
which would sink. The term used to describe floating is ?displacement?
and the precise mechanism is explained on a molecular level but that
needn?t concern you. Think of an example though -- a hollow steel
ball. If the ball has a volume of one litre and it weighs less than a
kilogram it?ll float because one litre of water weighs one kilogram.
Does that help? Maybe I can put it more simply -- if the weight of an
object is less than the weight of the same size of water, it?ll float.

Subject: Re: Ocean salt water and density of a boat
From: racecar-ga on 23 Nov 2004 12:16 PST
I'm not sure that the density of oatmeal is greater than that of
water.  The reason a slice of fruit "floats" on top of oatmeal is that
oatmeal isn't really a liquid.  A slice of fruit will "float" on top
of a dry bowl of rice crispies too.
Subject: Re: Ocean salt water and density of a boat
From: tutuzdad-ga on 23 Nov 2004 15:40 PST
I guess it really depends on how runny YOUR oatmeal is as opposed to
mine, doesn't it?



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