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Following up on John Clement's comments about gasoline and oxygen, I
found when teaching a distance education version of Matter &
Interactions for in-service high school physics teachers that many of
them were surprised to discover that they had been carrying around a
view of binding energy that was basically backwards, with the wrong
sign. The view was something like "there is energy stored in the bonds
in the gasoline molecules which we can use" instead of "in combustion
the molecules transition to a lower energy state and become more
bound". To put it another way, they seemed to have thought that "more"
in the bonds (more binding) meant more "bond" energy was available,
instead of more bonding being associated with lower energy, not higher.
I'll admit I can't express the issue very clearly, but the teachers
themselves were convinced that useful energy resulting from
transitions to lower energy levels (greater binding) was a new idea for them.
Bruce
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