Prepared by Mrs' S' Bolyard, Librarian

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How Do Hot Air Balloons Fly

• PowerPoint Presentation
• Prepared by Mrs. S. Bolyard, Librarian

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Floating
In a
Sea
of
Air

• To fly, the balloon has to be lighter than air.

• Air is made of tiny moleculesfar too small to be
  seen.

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AIR
HOT!

• When air is heated, the molecules need more space
  and they move farther away from each other.

Cold Air
Hot Air

• A balloon filled with hot air will have fewer air
  molecules inside and will weigh less.

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To heat the air...

• A heater/burner unit is used to heat the air
  inside the balloon. It is held there by the
  frame.

• The burner uses LP Gas just like a barbecue.

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Air, air, and more air

• Balloons are huge and contain about as much air
  as 4 houses.

• Air inside the balloon must be heated quickly.
  Fast burning gas makes a lot of noisea whooshing
  sound.

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Gas Balloons
Fly because the gas contained inside the balloon
is lighter than air.

• Hydrogen is about 1/7 the weight of air, but is
  highly flammable.

• Helium is almost as light as hydrogen, and it
  doesnt burn but it is very expensive.

To make the balloon climb, water or fine sand is
thrown overboard.

• Gas ballooning is almost completely silent!

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What's What

• air-spilling cordconnected to an opening at the
  top to let out some air

• Aeronautthe pilot of a balloon

Envelopethe fabric part that contains air

• fan/gasoline-powered fan

• Mouthopening at the bottom

• fire/flames

• Burnerdevice used to burn the propane and heat
  air

• Draglineconnected and used by crew on the ground

• Gondola/basketwhere the people ride

• Propane/fuel tanks

• burner cord

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...don't forget the weather
Flights should be planned for days when its cool
or cold outside.
and when the winds not blowing.
and theres a low probability of rain.
Early morning or evening are usually good times.
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Resources
Launch a High Flying Hot Air Balloon Smithsonian
Institution, c1998, p 7, 11. www.flymetothemoon.co
m.au/ www.barrysclipart.com Photographs taken at
the 2001 Mountaineer Balloon Festival