A balloon provides a simple example of how a rocket engine
works. The air trapped inside the balloon pushes out the open
end, causing the balloon to move forward. The force of the
air escaping is the "action"; the movement of the balloon
forward is the "reaction" predicted by Newton's Third
Law of Motion.
The distance that a balloon will travel when restricted to
a straight line is related to the amount of air trapped inside
the balloon when it is released. Similarly, the distance a
rocket will travel is related to the amount of fuel trapped
inside the rocket engine and the properties of that fuel.
This experiment will allow us to investigate how filling
balloons with different amounts of air affect how far they
will travel along a straight path. In order to do this, we
need a few equations....
Volume of a sphere: (the amount of air
in the sphere)
Volume = 1/6 x PI x (Diameter)3
Circumference of a sphere: (how far around
the sphere is )
Circumference = PI x Diameter
Diameter, as computed from the Circumference:
Diameter = Circumference/PI
PI = 3.14 (a constant value)
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