Ask A Scientist Botany Archive

name         Lynna B.
status       educator
age          40s

Question -   Can you tell me an experiment that can be done with
students ages 5 and 6 to show them why leaves change color?  Or that
although the leaf appears green other colors are not yet visible?
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You can have them rub a leaf onto a piece of filter paper.  They must rub
pretty hard with a coin so a dark line appears on the paper.  Have them
immerse the filter paper in alcohol so that the paper is immersed, but the
color is above the alcohol line (otherwise the color will leach into the
alcohol).  As the alcohol is sucked up into the paper, it will carry the
pigment with it.  The different pigments will separate according to their
mass.  They will see that even though the leaf appears green, there are
other
colors there also, usually two types of yellow pigments.  You can also
repeat
this later after the leaves have changed color to show that the green
pigments are gone but the other ones are still there.
vanhoeck
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