CATAPULTS
Physics, Background and History
Definition
 A machine that converts POTENTIAL
ENERGY into mechanical motion or
KINETIC ENERGY”
 Comes from the Greek word
“Katapultos,” meaning “shield
crusher”
 AKA: Siege Engine or Siege Machine
The Invention
 The catapult, as we would recognize it
today, was invented by the Greeks about
399 BC but various forms were found in
central Asia much earlier than that
 During the war with Carthage, Dionysius
of Syracuse produced the Gastraphetes or
“belly bow” catapult
The Invention continued…
 By 330 BC two distinct types of
catapults emerged
 One fired javelins (spears) called a
Euthytonon
 The other was the stone throwing
Palintonon
How was it used in Medieval times?
 First we need to understand the society
of the Middle Ages
 Fear was rampant (AKA: Dark Ages)
 There was huge disparity between the
rich and poor (Feudalism)
 Castles were constructed to protect
nobles (& peasants but only during
crisis)
Castle construction
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
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Moat
Draw bridge
Portcullis
Guard tower/ Barbican
Murder holes
Portcullis
Catapult AKA
Siege Machine or Siege Engine
 What is a siege?
 One army surrounds an enemy,
keeping help, goods and water from
leaving or entering the castle
Medieval warfare
 Infantry (usually the poor)
 Archers (trained/ paid military)
 Battering Ram
 Psychological warfare
 Flaming shrubbery and brush
Dead, diseased bodies
Heads of tortured victims
Battering Ram
Catapult Structure & Design
A typical catapult has each of the
following:
 Arm
 Base
 Elastic Force
 Fulcrum
 Most catapults were made of wood
 The elastic force provided by twisted
rope, springs, saplings
 The fulcrum is the point of support
for a lever- which in the case of a
catapult is the arm
Factors Affecting Distance
 Mass of object being hurled
 Strength & flexibility of arm
 Mass of arm
 Length of the arm
 How far the arm is pulled back
 Angle of base or release (best angle?)
 Small transfer of energy into distortion
Types of Catapults
 Roman design and others found
during the Medieval period
Ballista
 Roman
 Double
armed – like
a bow
 Shot large
spears or
javelins
Mangonel or Onager
 French
 “Engine of War”
 Typical catapult
Trebuchet
 French meaning “to stumble”
 Used a sling with the arm
 Extremely accurate
 Most advanced of all catapults
Fixed
Counterweight
Trebuchet
Swinging or Hinged
Counterweight Trebuchet