The Water in your Glass -- What's it Been Up To this Past 4 Billion Years?
Scientific proof that the water in your glass has been through Cleopatra, Julius Caesar....and the dinosaurs!
Recently I filled myself an 8-inch drinking glass full of water. So what, you
might think. But just before beginning to drink it, I paused for thought. Am I
the very first person this water has ever been through? In the 4 billion years
that the oceans have been there? Out
of all the water in the vast oceans? Surely I must be the first. Surely! But
nevertheless, curiosity got the better of me and I decided to do a few
calculations.... and the results were staggering. You will never believe where
in its life this water has been!
Now almost all the water on Earth has been here since the planet first formed or
shortly thereafter, and it circulates around the world not just in the ocean
currents but also in the rain cycle, as the sun evaporates the topmost layer of
the oceans and creates clouds, which then float over the continents and condense
into falling rain, which then in turn runs down through the streams and rivers,
and back into the sea.
But is there so much water in the ocean that my glassful has never been consumed by another animal or plant?
And what are the chances that even a single molecule of my water has been
through, let's say, Julius Caesar? Let's work this out!
Well, to do this we must first calculate how much water old Julius drank in his
lifetime. Then we have to divide this amount into the total amount of water in
the oceans and lakes of the world. When we do this, we will obtain a tiny,
microscopic fraction -- the fraction of all the water there is, that Julius drank.
Next, we have to multiply this tiny fraction by the number of molecules in my glass, and that will be the number of molecules in my glass that have been through Julius. Of course, if the answer is something like 0.00001 of a molecule, then none of the water has been through him. But suppose the answer is 100 molecules. Or 1000? Or a million? Then, there will definitely be some water in my glass that has been through the old dictator.
Ok...let's begin.
First, how much water did Julius drink? Well an average sized male should drink 3.7 litres of water a day. This includes the water that makes up 90 per cent of the food he eats. Now he lived for 55 and a three quarters years, which is 20,363 days, give or take a gnat, and therefore the old guy swigged and troughed his way through 75,343 litres of water.
But what fraction is this, of the total amount of water on Earth? We need to
calculate the amount of water in the sea.
Well the surface area of the earth is 509 million million square metres, and 71
per cent of this is ocean. So the total area of the oceans is therefore 361
million million square metres.
But to calculate the volume of the oceans, we have to multiply this figure by the average ocean depth, which is 3,688 metres. This gives us a total volume of 1.3 million million million cubic metres! Now a cubic metre is 1,000 litres, so the volume of the oceans is therefore 1,330 million million million litres!
Now old Julius drank 75,343 litres in his lifetime. So what fraction of the oceans did he drink? We have to divide 75,343 by 1,330 million million million -- and the answer is.... 5.66 x 10 to the power of (-17), which is 0.0000000000000000566 of the ocean!
Next, we have to multiply this tiny fraction by the number of molecules of
water in my glass, to see how many of these molecules have been through Julius.
So we now have to calculate how many molecules of water there are in my glass.
Well an 8 inch glass which is 3 inches wide will contain 925 cc of water, which is 0.925 kg. And 1 kg of water contains 3.35 x 10 ^25 molecules. So my glass has 0.925 of this number, which is 3.1 x 10 ^25 molecules.
But Julius only drank 0.0000000000000000566 of this number, and therefore there
are 0.0000000000000000566 x 3.1 X 10 ^25 , equals 1,756 million molecules of
water in my glass, that have been through Julius Caesar !!! Whoa!!!
Now this is so incredibly large a number, that we can definitely say that some
of the water in my glass has been through Julius. No doubt about it.
At this point we also need to remember that all the water in the oceans, even
the water from deep down, will circulate completely around the world in about
950 years, and so over centuries all the water molecules from every place on Earth have completely mixed
together.
This means that the water that went through Julius will now have diluted all
around the globe, and so yes there is very definitely some water from him in my
glass.
Now we only chose Julius Caesar at random. There is nothing special about him. So
it's now a much simpler matter to work this out for other historical people too,
because all we have to do now is compare their body size and longevity with
Julius.
Here are a few results.
In my 8 inch glass of water....
Cleopatra ..... 1000 million molecules
Jesus Christ .... 1200 million molecules
The Viking, Ragnar .... 2900 million molecules
And --- wait for it -- the dinosaurs were so numerous, and were
around for so long -- 170 million years -- that half an inch of water in
every 8 inch glass has been in a dinosaur!
So the next time you pour yourself a glass of water, just look at it for a
second and pause to think.... it's been the tears of children, the sweat of
slaves, some of it has been in the dark depths of Loch Ness while some has been
drunk by a Tyrannosaurus Rex. All in the very same glass of water.
Cheers!
---- Michael Alan Marshall