When the balloon is not inflated, it has air in it. There is no pressure. When it is blown up it is filled with
carbon dioxide.
There are three forces that will slow or stop a rocket balloon. These three forces are friction, gravity, and
air resistance.
Friction is a force that resists the motion of one object or surface moving past another object or surface.
The straw rubbing against the fishing line is an example of friction. Another example of friction would be
the air pushing against the balloon.
Air resistance are air molecules pushing against pushing against an object. When the balloon is flying
through the air on a fishing line it is flying "forward" the air is pushing it "backwards" at the same time.
Gravity is the force of attraction between two objects. Gravity says" what goes up, must come down."
Gravity pulls the balloon and straw downwards so it drags against the fishing line.
Sir Isaac Newton made up the three laws of motion. He lived 500 years ago.
The first law of motion is: An object at rest will stay at rest and an object in motion will stay in motion
unless a force makes the object change its state of rest or motion. This means the rocket balloon won't start
until you let go of the closing (hole). It wont stop until it runs out of air or something is in the way of its'
path.
The second law of motion is: The acceleration of an object increases as the amount of force causing the
acceleration increases. This means the more air in the balloon the farther and faster it goes.
The third law of motion is: For every action force there is an equal and opposite reaction force. This
means, if you let go of the balloon, something would slow or stop it eventually.
The balloon slows down when it starts running out of air. It begins quickly. The more air in the balloon
the farther it travels.
Inertia
Inertia is a property of all matter. It makes an object that is not moving continue motionless unless some
force puts it into motion. Inertia also makes a moving object continue to move at a constant speed and in
the same direction unless some force changes the object's motion.
Inertia applies to the third law of motion. If there was no friction, gravity, or air resistance and the balloon
had everlasting air and the string went on forever, inertia would keep the rocket balloon moving.