Name: James M.
Status: educator
Age: 40s
Location: N/A
Country: N/A
Date: 2001-2002
Question:
What is an example of a mechanical to chemical energy
conversion I could demonstrate to my students?
Replies:
Some examples come to mind: 1. Stirring is a mechanical action that
promotes countless chemical reactions. It is so common we do not even think
about it. 2. The friction caused by scratching causing a match to ignite. A
similar application is the spark igniter used to light propane torches.
3. More sophisticated, pressure applied to a membrane separates pure water
from saline water. 4. Numerous chemical reactions where the number of moles
of gaseous reactants and products are not zero respond to a changes in
pressure.
Vince Calder
James,
I can think of a fairly simple one involving a hand generator and a
rechargeable battery. Be sure the generator puts out DC current. A diode
inserted wisely can be a quick solution if you have AC generators. Start
with the battery uncharged. Convert mechanical(hand) to electrical(current)
to chemical(battery).
If you do not want the electrical part, I would look toward toys. I have
seen toys that respond to pressure by changing color. By exerting the
pressure to squeeze the toy, you exert mechanical energy. This in turn
changes the color of a material: a chemical reaction of some sort. When
the material is allowed to expand, the chemical energy changes back to
mechanical energy (the toy pushing your finger away).
Dr. Ken Mellendorf
Physics Instructor
Illinois Central College
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