This Week's Experiment - #229 Old Water
Recently, I have been working on a new project involving water. An exhibit
design firm asked me to help them develop some unique, interactive exhibits
for a new museum that will focus on the science and history of water. I am
having a blast and we are coming up with all sorts of fun ideas. I am
currently playing with several different approaches to interactive exhibits
on the water cycle and thought that it would make an interesting Experiment
of the Week. For this one, you will need:
a glass of water
Go to the kitchen and get a glass of water. Look at it for a minute. Not
very interesting? That is because we are so familiar with the stuff. When
you begin to study water, you realize that it is an amazing chemical that is
unlike any other substance. For example, its chemical formula is H2O. That
tells us that each molecule of water is made up of two atoms of hydrogen and
one atom of oxygen. Now, hydrogen is a gas that burns very well, and can
produce quite an explosion. Oxygen is also a gas, and it also burns. In
fact, most things will not burn if there is no oxygen present. When you
combine these two flammable gases, you get a liquid that puts out fires!
One thing about water that fascinates me the most is that it recycles. Go
outside and pour a little of the water onto your driveway or sidewalk. You
get a nice big, wet spot. If you leave and come back later, the wet spot
will be gone. Where did it go? The water evaporated. It changed from a
liquid into a gas. The water vapor is now part of the air around you. If a
rising current of air carries the water vapor up high enough, it will
condense back into tiny droplets of water, forming a cloud. If there are
enough of these droplets, they can stick together enough to form drops large
enough to fall as rain. That rain water could wind up back in your water
supply, and one day some of the same water molecules might come out of your
faucet again.
Now take a big swallow of the water. Water is very important for our bodies.
As part of your blood, it helps carry nutrients and oxygen to the cells of
your body. Inside the cells, water plays an important role in the chemical
reactions that keep you going. It also carries the waste products of these
chemical reactions away from the cells. Eventually, it carries these waste
products out of your body, when you go to the restroom. Then what happens?
The water is carried through the sewer system and winds up back in the water
cycle. It evaporates, condenses, falls as rain, etc. One of these days,
some of those same water molecules may make the cycle all the way back to
your faucet, giving you a chance to drink them a second time. Now, I can
hear all of you saying "Gross!" and "Yuck!" Just wait. It gets better.
Most of our water is very old. To make new water, you need to form it
chemically, combining hydrogen atoms and oxygen atoms to make new molecules.
That does happen, but the vast majority of the water molecules in your water
system have been around for a VERY long time. They have been through the
cycle MANY, MANY times. They have been through MANY, MANY other creatures.
Before you start saying "Gross" again, pause for a minute and think about all
of the water molecules in your glass. Think about all of the history
involved. Some of the water molecules in your glass of water may have been
consumed by Benjamin Franklin or by Nikola Tesla. Some of them may have
passed through a blue whale or a Tyrannosaurus rex. Think about that for a
while. Think about what a wonderful thing the water cycle is. Then have
another big drink of water.
From Robert Krampf's Science Education Company
PO Box 60982
Jacksonville, FL 32236-0982
904-388-6381
krampf@aol.com
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