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Buoyancy
Force = r g V
Charles
Law: V1
/ T1= V2 / T2
Pressure
= Force/Area
Pressure
from a fluid = rgh
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Buoyancy
force is the push upward on a ( partly or completely)
submerged object in a fluid. This force from the fluid derives from
pressure differences at different levels in the fluid. Did you know
that
air is a fluid?
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Hot air
in the balloon is less dense than the colder air outside the
balloon. Thus the balloon floats as if it were a piece of wood in
water.
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A standard
hot air balloon has a volume of 1590 cubic meters
(56,000 cubic feet) which is larger than the average house.
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The propane
burner used to inflate the balloon has a power
rating typically between 2 and 3 MWatts.
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Important
instruments onboard are the altimeter (essentially a
barometer that measures height) and a variometer (this
measures the rate of climb or descent).
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A balloon
follows the wind and on board there is no wind. Your hair
will not become ruffled.
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Surface/volume
ratios are important. For a given surface, mass
density and temperature, there exists an optimum size needed for lift.
It's a matter of scaling.
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On March
20, 1999, Bertrand Piccard & Brian Jones became the first
aviators to circle the globe in a hot air balloon. Time: 19 days,
1 hr, 49
minutes. Distance traveled: 42,810,000 meters!
See Pictures of Hot Air Balloons My Students Made
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