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The "Pocket Knows" is only the latest in a long history of 'smelling'
devices, and the story of its development is quite remarkable.

In ancient times chemical sensing was more of an art form. When most
people were still hunters and gatherers, they relied on their real noses to
tell them if food was bad, and even where to find it. Later, during Medieval
times, kings had official taste testers whose job it was to make sure the
royal food wasn't poisoned. But this was a pretty risky job until people
could find better ways of detecting chemicals. Luckily, right about this time
the Alchemists, who were working hard at trying to make gold, started the
science of chemistry and chemical sensing. And even though they never
did get rich, we've been benefiting ever since.

Over the next couple of centuries, scientists came up with several ways to
detect chemicals. One of the most important methods is chromotography,
which separates molecules based on their "stickiness". Another is
spectroscopy, which identifies stuff based on the kind of light it absorbs or
gives off. But even though these methods have helped us to detect many
kinds of chemicals in our air, food, and water, a lot of people think that they
are too bulky, expensive, and just not sensitive enough.

That is why we decided to model real noses, especially when we looked at
how sensitive many animal noses are. Also inspired by how real noses
work, several scientists in just the last two months have come out with the
first of these "E-Noses," or "Electronic Noses," which are small enough to
carry around and can detect many different kinds of substances.

However, all of us still have a great deal of work in the next twenty years to
develop a powerful all purpose "electronic nose" that can rival a real nose
like that of Jake, your pet Beagle. In order to make the "Pocket Knows,"
microprocessors have to get much smaller and more powerful. We also
have to find better ways to design and custom make polymers that can
react to a specific odor. And don't forget, all this has to be affordable!

It's only taken a few thousand years, but soon everyone will be using their
"Pocket Knows" to hunt for crayfish and gather blackberries. Ok, maybe
not the adults, but kids will still be out hunting and gathering, and to
someone tracking down a big game chipmunk, a better nose would be
pretty neat.

Don't you wish it was the year 2020 today!