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Hot Air Balloonists... Scientists in Action

• Created By
• Amy Taylor
• Hazelwood Central High School

To Teacher Page
To Activity
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Teacher Page

• Grade Level 10
• MAP Content Standards
• The learner will be able to describe how the
  arrangement and motion of molecules cause
  different biological, chemical, and physical
  phenomena.

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• Tips for Classroom Use
• Preview the activity before using it with your
  class
• This activity is recommended for use after the
  concepts of density and kinetic molecular theory
  have been introduced.
• Journaling
• This activity is intended to be used in
  conjunction with journaling.
• The notebook icon will prompt the students when
  to journal in their notebooks.

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If you would like to construct a miniature hot
air balloon with your class, there is an
excellent website athttp//www.overflite.com/rose
bud.htmlthat gives directions, safety
precautions, and even the calculations involved
to make ballooning a memorable learning event.
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Focus on the process of problem solving with
your students they need to understand not only
the facts, but the reasoning behind them. Have
them write their thoughts on paper and then
discuss them as a class.
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Hot Air Balloonists... Scientists in Action
What makes a hot air balloon float?
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You have recently been studying the gas laws...

• In your own words, what does Boyles Law mean?
• What does Charles Law mean?
• Daltons Law?

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• These laws are applied in our daily
  livesalthough we are usually completely unaware
  of their significance.
• One of them can be used to explain how a hot air
  balloon works.

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A Brief History of Ballooning

• 1783 several Frenchmen sent up balloons, and
  French physicist Jean François Pilâtre made the
  first human balloon ascent.
• During both the Franco-German War of 1870 and
  World War I (1914-1918), balloons were used for
  military observation.

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Lets look at the mechanics involved...

• A propane heater is used to heat the air in a
  large sack.
• When this happens, the balloon is filled.
• The filled balloon becomes buoyant and is able
  to float on air.
• By heating or cooling the air inside the balloon,
  the balloonist can control the altitude of the
  balloon.

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Form a hypothesis to explain why a hot air
balloon floats.
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Double

• Is your hypothesis written as an ifthen
  statement?
• Does your hypothesis briefly describe the problem
  and offer an explanation to explain the
  situation?
• Discuss your hypotheses with your class.

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The Answer...

• CHARLES LAW! As the TEMPERATURE of the air
  inside the balloon rises, the VOLUME increases.
  When the air particles spread out, the DENSITY of
  the air inside the balloon is less than that of
  the surrounding air and the balloon floats.
• How did your hypothesis compare?