Chromatography is handy when you have something
that looks like it's one color, but is actually
made of many colors. Most leaves are green,right?
But here in Wisconsin, the leaves are turning
gold, orange, red,and yellow. What's actually
happening is that those reds and yellows were
already in the leaves, but the trees are taking
the most valuable pigments out of the leaves to
store for next year's leaves. The
colors(pigments) that we think we see are actually
made of several pigments.
chromatography separates all of the different
pigments out, so we can see each on by itself.
Water molecules stick to each other. That's why
you can fill a glass to the top, then carefully
add drops of water and make a "hill" of water
above the glass. Water will also stick to
pigments. In chromatography, you let water (or
another solvent)dissolve the pigments, then let
the water slowly move up a piece of paper. Not
all of the pigments move at the same speed, so
they separate out.
Think of a whole crowd
of people getting ready to start a race. They're
all bunched together. After they run for a while,
the fastest will be up front, and the slower
runners will lag behind. If you make everyone
stop at the same time, you can see all of the
runners clearly. (Of course, if you let them
finish the race, they'd all bunch up again,that's
why we stop chromatography before the water goes
all of the way to the top.)
several great sites that show you how to do simple
chromatography. Here's one, and once you are in,
click on "experiments" and type chromatography for
do you think plants are green, anyway? And why do
you think they have several pigments instead of
just green?Hint: read up on light
wavelengths.Thanks for asking,
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