Outdoors Catapult
By: Ben Wynett and Garrett Lusk
Purpose
 Our objective was to build a catapult out of
materials that you could typically find in the
outdoors.
Materials

Thick sticks for the base and thin sticks for the legs

Masking tape

Thread and yarn

Scissors

Leaves

Rubber bands

Small rock

Life Saver gummy

Ping Pong ball
Yarn for stability
The Final Product
Side Note:
The red
rubber bands
serve as the
catapult, and
the orange
yarn provides
stability.
Rubber bands
Diagram
This is one of
six joints. The
joints are
connected by
yarn and
masking tape.
One of the four
base structures
Basket for
projectile
One of four
leg
structures
Launcher. What
we pull back to
launch projectile
Sample Launch Video
This was not one of our
best launches, in fact it
was one of the first, but
this can allow you a look
into the basic mechanics
of how it works.
Procedure
1.
Gather necessary materials
2.
Construct the base by using thread and tape
3.
Connect the legs to the base by using thread and tape
4.
Attach yarn to all of the joints to increase the structure
5.
Place the rubber bands on the legs to prepare for the launching
motion
6.
Place our projectile on the catapult, launch it, then collect the
data to predict our total kinetic and potential energy produced
by the Catapult.
Data Collection
 We launched 3 different objects: life saver, small
rock, and a ping pong ball.
 With these data, we will find the Kinetic and
Potential energy using the equation: KE=1/2mv2
 Once we find the Kinetic Energy, we know that the
Kinetic energy is equal to the Potential Energy, so
once we know one we know the other.
Data
Item
Launch
Degree
Range of
Flight
Small
Rock
50
Degrees
LifeSaver
Gummy
50
Degrees
Ping Pong 50
Ball
Degrees
Time of
Flight
Mass
Velocity
Kinetic
Energy
5.3 meters 2.15
seconds
.00107 kg
2.46 m/s
.017
Joules
2.3 meters 1.61
seconds
.000145
kg
1.43 m/s
9.2x10-4
2.03
meters
.00009 kg
1.34 m/s
1.52
seconds
Joules
8.1x10-5
Joules
Life Saver
 Launch Angle: 50 degrees
 Range of Flight: 5.3 meters
 Time of Flight: 2.15 seconds
 Mass: .000145
 KE= .017 Joules
Small rock
 Launch Angle: 50 degrees
 Range of Flight: 2.3 meters
 Time of Flight: 1.61 seconds
 Mass: .00107 kg
 KE= 9.2x10-4 Joules
Ping Pong Ball
 Launch Angle: 50 degrees
 Range of Flight: 2.03 meters
 Time of Flight: 1.52 seconds
 Mass: .00009 kg
 KE= 8.1x10-5 Joules
Analysis
 Our objective was to figure out what the kinetic and
potential energy would be if we launched 3 different
objects: life saver gummy, small rock, and ping pong ball.
 We used the equation: KE = ½ mv2
Life Saver
 KE = ½ (.00009)(2.52)2
 KE = 9.2x10-4 Joules
 The potential energy is equal to the kinetic energy
 PE = 9.2x10-4 Joules
Small Rock
 KE = ½ (.00107)(1.43)2
 KE = .017 Joules
 The potential energy is equal to the kinetic energy
 PE = .017 Joules
Ping Pong Ball
 KE = ½ (.00009)(1.34)2
 KE = 8.1x10-5
 The potential energy is equal to the kinetic energy
 PE = 8.1x10-5
Conclusion
 We ultimately figured out how to make our catapult, and we
were satisfied with our progress.
 We faced many problems while we were working on our
project:
1.
We struggled with using materials out of the woods, so we had
to resort to materials such as yarn and tape to connect the
different parts together.
2.
The basket that we made for placing the object into kept falling
apart, so we had to reconstruct our basket a few times.
Bibliography
 The only resource that we used was this YouTube video
 Builds, Josh. "How to Make an Easy Catapult." YouTube.
N.p., 7 Oct. 2013. Web. 11 Dec. 2014.