easy chlorophyll fluorescence
Virginia.Berg at uni.edu
Mon Mar 27 11:42:14 EST 2000
Here's a low tech way to show chlorophyll fluorescence to even a large
audience. It can be done in your kitchen, if you have good enough ventilation.
In a blender, blend acetone & spinach leaves (blades). [I think we've even
gotten this to work with frozen spinach.] Strain through several layers of
cheese cloth, saving the liquid in a glass container. Hold the container up
in the light path of an overhead projector (after all the hardware, on the
way to the screen). The fluorescing side will face the audience, assuming
the audience is facing the screen. A slide projector would do as well,
again aimed toward the front of the room from the back. It's easy to see as
long as the room lights are out.
You can also hold an Erlenmeyer flask just above the "bed" of the overhead
projector, tilted a bit so the bottom of the flask is visible to the
audience. You just need enough acetone to cover the bottom when tipped.
Actually, a peanut butter jar would work here, too, but the large bottom of
the Erlenmeyer is useful here.
I used to do things with small containers of chlorophyll, and microscope
lamps, etc., but discovered that the fluorescence shows even better with a
large container, as long as there is the bright light source of the OHP. We
even keep the solution for an extra year or two--lazy, I guess.
Of happiness and sorrow it is man who decides.
Only good fortune and the length of life we cannot control.
-- Tibetan proverb
Virginia Berg (bergv at uni.edu)
Biology Department 0421
University of Northern Iowa
Cedar Falls, IA 50614
(319) 273-2770 (phone), 273-2893 (fax)
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