This week's experiment comes from
a question that was sent to me by Hashi, one of the members of the
Experiment of the Week list. He noticed that smells were stronger while taking
a shower and asked why. To investigate, you will need:
salt pepper dust your hot water faucet other things that smell
Lets begin with some pepper.
Sprinkle some pepper onto your hand. Hold it about a foot from your nose and
sniff gently. Do you smell the pepper? If not, move it a little closer and
try again. Be careful not to sniff the pepper up your nose, as that is
very unpleasant.
Now lets try it again, but this
time go to the sink. Turn on the hot water and let it run until it gets nice
and hot. Leave the water running and place your hand above the sink. Now
sniff the pepper again, starting at least a foot away. You should find that
you the smell of the pepper is much stronger and can be smelled farther away.
Try this again using salt instead
of pepper. Unless your nose is much better than mine, you will have to get
VERY close (Read that as my nose in the salt) to smell the salt under normal
conditions. When I tried it with the hot water, I was surprised at how
much stronger the smell was.
Why? Several weeks ago, we saw
that if your tongue is dry, you cannot taste things. Some liquid is required
to carry the flavor to your taste buds. Our sense of taste and sense of smell
are closely related. The increased humidity in the air "wets" the
molecules, making it easier for you to smell them. The smell of the salt was
in the air, wet or dry, but you needed the help of the humidity to smell it.
This also plays a part in the
"smell of rain." Searching the internet, this lead me on a merry chase. I found
references saying that this smell was due to everything from ozone produced
by lightning (which you should smell after the storm, not before) to oils
released by plants in response to changes in air pressure. These to sometimes
play a part, but most people seem to miss the impact of the suddenly
increased humidity.
Go out and get some dust from the
front yard. Find a patch of nice, dry dirt and scoop up a little. Smell it,
just as we did with the salt and pepper. Now take it inside and try it
with the hot water running. You should smell a very familiar smell which most
people associate with rain. Much of the smell that people call the "smell of
rain" is actually the smell of dust in the air. The increased humidity of
the coming rain just suddenly makes the smell stronger, allowing you notice it.
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