Alan,
Thanks for sending the info on the nutritional and other
benefits of bananas.
Related to this, I've been gathering energy-content
information on various things for an article I hope to write
about energy and power.
Interesting fact: The energy content of a banana is about the
same as that of a hand grenade, about 170 calories, or 7E5
joules.
If, as what you sent points out, a 90-minute workout can be
sustained by 170 calories (7E5 joules), then the total metabolic
power comes to only 130 watts, of which ~25% (~30 watts) might go
to the doing of actual physical exercise with your arms and
legs.
Compare that 130 watts (joules of energy per sec) of power to
the power of 2,000 calories of food energy per day, which is only
100 watts. I.E., OUR SOLAR-POWERED BODIES OPERATE ON AN
AVERAGE AMOUNT OF POWER EQUAL TO THE RADIATED POWER OF A TYPICAL
LIVING ROOM LAMP. To me, that is interesting. To others, it
probably isn't interesting at all -- which relates to the
challenge one faces in trying to write a popular article about
energy and power . . .
I estimate that when I ride my bike at an average speed of 12
mph in the mildly hilly terrain of N.W. Washington, that I'm
pumping about 100 watts to the rear wheel, and my TOTAL metabolic
energy is close to 400 watts. (BTW, and for comparison to that
estimate, an article in a recent issue of Science magazine cited
650 watts of total metabolic energy for a "fast walk," of which
about 25% goes to actually walking, while the rest to pumping air
and blood, thinking [about politics and grocery lists and
cleaning the gutters], and to inevitable thermodynamic losses at
the cellular level.)
As for 'power,' the 170 calories of energy in a banana can
provide 750 watts of TOTAL metabolic power for 16 minutes. That
many watts is 1 horsepower, of which about 1/4th horsepower could
be directed toward doing physical work, such as walking up
stairs.
If that same 170 calories were released in a thousandths of a
second, as with a hand grenade, you get nearly a million
horsepower. (A banana could also be detonated if you used nitric
acid to nitrate its carbohydrate portion. Nitrobanana's could be
made -- which is probably why nitric acid is so difficult to
buy.)
Sort of related to this energy/power thing is this: The energy
content of 10 gallons of gasoline is about the same as 500 lbs of
TNT. Also, the kinetic energy of a bullet coming out of the
barrel of an M16 rifle is about one-quarter of a calorie -- i.e.,
food calorie; the energy in a Krispy Kreme is enough to kill a
thousand people.
Sort of related, too, is this: If our bodies could use the
energy in gasoline at the current local price of $2.32/gallon,
daily food-energy cost would be ~15 cents. The equivalent energy
in health-giving bananas would be several dollars. Count
yourself lucky that you don't have to fuel that big truck of
yours with bananas.
later,
Bob
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