Introduction:
  Have you ever seen a hot air balloon soaring high in the sky?  How did it get so high?  A hot air balloon does not have a combustion engine and a propeller like an airplane, yet it can fly.  An airplane combusts fuel (gas) and air into energy, which it uses to fly.  A hot air balloon, like its name, uses fuel (gas) to create hot air that makes the balloon soar through the air when the hot air rises.
 A hot Air balloon consists of a huge nylon balloon, A hot air engine, and a large basket.  The hot air engine fills the balloon with hot air.  Hot air rises, and once the balloon is filled with hot air, it rises as well.  A valve in the engine controls the amount of hot air allowed into the nylon balloon.  When the balloon’s pilot wants the balloon to soar higher, he opens the valve and lets in more hot air.  When he wants the hot air balloon to descend, he closes the valve.

Objectives:
1. The students will demonstrate their knowledge of hot air balloon’s by making a miniature hot air balloon out of K’nex toys.
2. The students will explain how and why a hot air balloon works.
3. The students will describe the difference between the engine in an airplane and the engine in a hot air balloon.

Procedures:
 After learning all about hot air balloons, how they work, how they differ from other flying machines (airplane), the students will design the structure of a hot air balloon using K’nex toys.  The K’NEX hot air balloon models will be used to review the points learned about hot air balloons and how they work.  The children will then be tested on their acquired knowledge of hot air balloons.

      Source:
                                                            Ramsey, Gabriel and McGuirk, Holt General Science  Holt Reinhart and
                                                                        Winston, publications.  New York. 1983.
 
 

Evaluation:
 If the students are able to:
1. Create a successful model of a hot air balloon out of K’nex toys
2. Explain how a real hot air balloon works
3. Explain how a hot air balloon is different from other flying machines
 They have successfully understood the concepts covered.