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Chapter 2: The
Answer, My Friends, Is Blowin in the Wind
Whoa, Smelly, whoa!
Here we are on the outskirts of a big city. A big city means lots of
people and lots of people means lots of garbage. I know there’s a big
ol’ garbage dump just over that hill ‘cause I can smell it. Peee –
yewww!
Now how is it that I
can’t see the garbage dump, but I can still smell it? Well sir, if
we’re going to answer that question, we’ll need to learn a thing or two
about chemicals and molecules.
Let’s start with the
chemicals. Everything from a peach to a pillow is made of chemicals.
Some chemicals are smelly or odorous. For example, both ripe
bananas and rotten eggs contain odorous chemicals. However, ripe
bananas contain a chemical that smells sweet and pleasant while rotten
eggs contain a chemical that smells gross and disgusting.
Well now, odor
molecules are the smallest parts of odorous chemicals. This is true
for all things containing smelly chemicals, from fragrant peaches to
reeking sneakers. Invisible to the eye, tiny odor molecules float off
stinky things and are carried into the air.
Although you can’t
see air, that doesn’t mean it’s empty. On the contrary, the earth’s air
is made up of tiny gas molecules too small to be seen. That’s right,
they’re invisible! Sneaky little things, aren’t they?
Well folks, the air
around us contains billions and billions of gas molecules. Perhaps
you’ve heard of gases like oxygen and carbon dioxide. In the air around
a garbage dump there are also millions of invisible odor molecules
rising up from stinky chemicals in spoiled milk, dirty diapers and moldy
meatloaf. Constantly moving gas molecules in the air spread the odor
molecules around, and on a hot summer day like today, the odors sure are
strong. Pee-yew!

One stinky chemical
found in a dump is ammonia. Ammonia comes from old baby diapers
and used kitty litter, among other things. Its odor molecules smell
very unpleasant. It’s a good thing we perceive its smell as unpleasant
because ammonia is harmful to your health. Tiny amounts of ammonia in a
wet diaper can irritate a baby’s skin. This is known as diaper rash!
When there’s lot’s of it around, ammonia irritates your eyes and makes
them water. It can even burn your lungs if you inhale it. So an old
diaper’s stinky smell is like a flashing yellow light signaling
“caution, danger ahead!” Let’s high tail it out of here! Giddy-up,
Smelly!
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