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Q: Weight of Earth's salt water. ( Answered 4 out of 5 stars,   1 Comment )
Subject: Weight of Earth's salt water.
Category: Miscellaneous
Asked by: pdy-ga
List Price: $10.00
Posted: 28 Mar 2006 23:04 PST
Expires: 28 Apr 2006 00:04 PDT
Question ID: 713034
Plus or minus %10 percent what is the total weight, in tons, of all the
salt water on Earth?
Subject: Re: Weight of Earth's salt water.
Answered By: palitoy-ga on 29 Mar 2006 00:46 PST
Rated:4 out of 5 stars
Hello pdy-ga,

Thank-you for your question.

First of all I should note here that it is difficult for these numbers
to be exact because of a number of factors; most notably the volume of
saline water on the Earth is only an estimate and the density of
saline water can also alter (depending on a number of factors).  That
being said we can calculate the mass of saline water on Earth using a
few simple facts.

An estimate of the total volume of saline water on the Earth can be
calculated from this page:

The table gives:
Oceans, Seas, & Bays - 1,338,000,000 km3
Saline Groundwater - 12,870,000 km3
Saline Lakes - 85,400 km3

This is a total of 1350955400 km3 of saline water.

Using we know that 1 km3 is the same as
1000000000 m3.  Therefore the total volume of water in cubic meters is
1350955400 x 1000000000 m3 or 1350955400000000000 m3.

According to the Wikipedia the concentration of sea water (which makes
up the vast majority of the saline water in the world) varies from
1020-1030 kg m-3.

Therefore we can calculate an approximate upper and lower limit from
this density figure.

Lower:  1020 kg m-3 x 1350955400000000000 m3 = 1377974508000000000000 kg
Higher: 1030 kg m-3 x 1350955400000000000 m3 = 1391484062000000000000 kg

One metric ton is equal to 1000 kg.  This gives our lower estimate a
value of 1377974508000000000 tons and the higher estimate a value of
1391484062000000000 tons!

Because of the inaccuracy of these numbers (see my opening comments)
we should probably quote the mass of salty water to be approximately
1.38x10^18 tons.

I hope that this answers your question.  Should you require any
further assistance on this matter please do not hesitate to ask for
pdy-ga rated this answer:4 out of 5 stars
Well done.

Subject: Re: Weight of Earth's salt water.
From: rainbow-ga on 28 Mar 2006 23:15 PST
This may interest you:

What percentage of Earth's water is saline?
Answer: About 97.2% of Earth's water is saline water, located in the
oceans and seas.


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