THE CATAPULT PROJECT
In ancient and medieval times, a catapult was a mechanism used to throw missiles. At first,
catapults were specifically designed to shoot spears or other missiles at a low trajectory. They
were originally distinguished from ballistae and trebuchets, both of which were large military
engines used to hurl stones and other missiles, but these distinctions later blurred. Soon after,
larger catapults mounted on a single arm also hurled stones, pots of boiling oil, and incendiaries
at a high trajectory. They were used to attack or defend fortifications. Catapults were widely
employed in siege warfare, but with the introduction of artillery they passed from use. In the
20th century catapults using hydraulic pressure were reintroduced to launch aircraft from warships.
OBJECTIVES:
The goal of this project is to increase your understanding of projectile motion by building a
catapult (to launch a ping-pong balls), and by collecting and analyzing data.
ASSIGNMENT:
(The teacher will pre-select teams of 5 to 6 students.)
Each team must construct a catapult that can launch a ping-pong ball at various angles on
a consistent basis. You must use the materials given to your team (i.e. you may not add
other materials to your catapult.) To learn how to construct a catapult you may either do
your own research or check out the links provided below.
DATA COLLECTION:
Launch your ping-pong ball at three different angles – one less than 45o, one equal to 45o, and
one greater than 45o. For each launch angle, collect and record the following data in a table:
- launching angle
- range of flight
- time of flight
Data Table
Launch Angle (o)
Range of Flight (m)
Time of Flight (s)
ANALYSIS:
Using the data your team has collected, determine the following:
-
the initial velocity of the ball
the initial horizontal and vertical components of velocity
the time to the maximum height
the maximum height
the velocity of the ball upon impact
DIAGRAMS:
Use a drawing tool to draw a neatly labeled diagram showing:
1. the ping pong ball’s acceleration at its initial, maximum and final heights.
2. the force(s) acting on the ball at its initial, maximum and final heights.
3. the ping pong ball’s velocity (and its components) at its initial, maximum
and final heights.
PRODUCT:
Your final product must be a PowerPoint, Prezi, PreZentit or some other format approved by
your teacher. It must contain:
-
-
a title slide
a picture of your team with your and catapult
a slide showing the 3 neatly drawn diagrams
3 Data Table slides
a slide showing the calculation of each of the following (initial velocity, the initial
horizontal and vertical components of velocity, the time to the maximum height, the
maximum height, and the velocity of the ball upon impact)
a reference slide
Note:
PreZentit can be used to create presentations in a few clicks, wherever you are. You can work with
your team in the same presentation at the same time. Your presentations can be private or public.
Each presentation has its own web address. Download your presentations and show them even without an Internet connection. The presentations are web pages (HTML) so they can be edited manually.
http://prezentit.com/
LINKS:
How does a Catapult work?
How to Build a Catapult
Trebuchet Physics
Catapults
The Catapult
NOVA: Medieval Siege
History of Trebuchet
Catapult Simulation
Scoring Rubric:
Requirements
Points Possible
Title Slide
Team Picture with Catapult
3 Data Table Slides
Initial Velocity Slide
Components of Velocity Slide
Time to Reach Max Height Slide
Maximum Height Slide
3 Neatly Labeled Diagrams
Reference Slide
1
1
3
3
4
3
3
3
1
22
Total
Points Received