Activity: Controlled
Propulsion Experiment  Balloon
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)
