C A T A P U L T SC A T A P U L T SPhysics, 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

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 brushDead, diseased bodies Heads of tortured victims

Battering Ram

A typical catapult has each of the following:

Arm Base Elastic Force Fulcrum

Catapult Structure & Design

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