Names:_________________________________________________ Date:_____________________
Balloon Rockets and Newton’s Laws
Balloon Rockets = 75 points total
Data = 33 points (1 point for each piece of data and calculation)
Questions = 33 points
Returning materials and cleaning up = 9 pts
Background Information:
Newton used three laws to describe all aspects of motion.
Newton's First Law of Motion states that an object at rest will remain at rest and an
object in motion will remain in motion at a constant velocity unless acted upon by an
unbalanced force.
Newton's Second Law of Motion states that force, mass and acceleration are related. It
is commonly summarized by the formula: Force = mass x acceleration.
Newton's Third Law of Motion states that for every action there is an equal and opposite
reaction. Forces always act in pairs.
Things to Remember:
- Speed is the measure of the rate of motion. Speed = distance time.
Balloon Rockets
Rockets use Newton's third Law of Motion to propel them. The balloon rocket is
powered by escaping air using Newton's Third Law. Its motion is determined by
Newton's First and Second Laws.
Hypothesis: Newton's Laws of Motion can be used to explain a rocket's motion
because Newton's Laws explain all aspects of motion.
Materials:
3 different sized balloons Tape
Drinking straws Meter stick
String Stopwatch
Procedure:
1. Set up your rocket course according to the diagram below… you can use any of the
following to tie the ends of your string to… 2 desks, 2 chairs, 2 drawer
handles
2. Blow up the balloon but don't tie it closed. Carefully tape the balloon to the straw with
the open end of the balloon pointing away from the starting line.
3. Line up the starting point with the front of your straw.
4. The person holding the stopwatch says "Go" and starts the stopwatch as the person
holding the end of the balloon lets go.
5. Stop the stopwatch when the balloon stops. Record the time in the appropriate data
table.
6. Measure the distance from the starting line to where the front end of the straw
stopped. Record the distance in centimeters.
7. Repeat steps 3 through 6 two more times with the same balloon. Try to blow up the
balloon so that it is the same size each time.
8. Repeat steps 2 through 7 with your second balloon of a different size.
9. Repeat steps 2 through 7 with your third balloon of a different size than your first or
second balloon.
10. Calculate the average speed for each trial and then the overall average speed for each
of the three balloon rockets.
First Balloon used: SMALL BALLOON
First Trial #1 Trial #2 Trial #3
Balloon
Distance
Time
Speed
Average Speed of three trials:____________________
Average time of the three trials:___________________
Second Balloon used: MEDIUM BALLOON
Second Trial #1 Trial #2 Trial #3
Balloon
Distance
Time
Speed
Average Speed of three trials:____________________
Average time of the three trials:___________________
Third Balloon used: LARGE BALLOON
Third Trial #1 Trial #2 Trial #3
Balloon
Distance
Time
Speed
Average Speed of three trials:____________________
Average time of the three trials:___________________
Questions:
You must answer the questions using complete sentences. Thorough explanations are
required.
1. What force caused the balloon rocket to move forward? (3 pts)
2. Find the acceleration of each balloon using the acceleration formula: a = (vf – vi)/t
Because the balloons started from rest the initial velocity is 0 m/s. Use the average
speed for each balloon as the final velocity and the average time for the time. Don’t
forget the appropriate units with your answer: (2 pts each)
a. Acceleration of balloon 1:
b. Acceleration of balloon 2:
c. Acceleration of balloon 3:
3. Compare the average acceleration for each balloon rocket. (2 pts each)
a. Which balloon has the greatest average acceleration?
b. Which balloon has the least average acceleration?
c. Why do you think one type accelerated faster than the other?
4. Compare the forces acting on each balloon. (2 pts each)
a. Which balloon had the greatest force acting upon it and causing it to move?
b. Which balloon had the least force acting upon it and causing it to move?
c. Why were the forces acting on each of the different balloons not the same?
5. Explain how Newton’s 3 Laws were observed in this lab: (4 pts each)
a. Newton’s First Law (“Object tend to keep doing what they’re doing (either
moving or resting” until an applied force causes them to do something else”):
(HINT: Think about how Newton’s first law applies to why the balloon started
moving and why it eventually stopped moving)
b. Newton’s Second Law (Gives the relationship between force, mass and
acceleration): (HINT: Think how Newton’s 2nd law applies to why the balloons
had different accelerations from each other.)
c. Newton’s Third Law (“For every action force there is an equal but opposite
reaction force”) (HINT: Think come up with a pair of action and reaction forces
that relate to why the balloon moved forward… don’t forget to compare the
relative strengths and directions of the action and reaction forces.)