Torpedoes, Missiles, and Cannons: Physics Goes to War
BOWS AND CATAPULTS Bows and arrows were first used in the Stone Age Native peoples in the Americas Asia and Africa continued to use bows as weapons until the nineteenth century Fhe bow is a simple but efficient weapon It I consists of a bowstring tied tightly between two ends of a curved piece of wood The ends of the bow act as levers The archer's hand acts as the fulcrum The archer draws the arrow back in the bowstring to create tension English archers right meet French soldiers armed with crossbows left at the Battle of Crécy in
SCIENCE FILE When the archer releases the string it propels the arrow forward Bows create kinetic energy so the arrow travels quickly and creates a powerful force In the Middle Ages when soldiers began to wear armor an arrow with a steel tip could penetrate even thick metal armor ARROWS IN BATTLE In ancient times groups of archers on foot or on horseback fired hundreds or thousands of arrows at the same time The rain of arrows they created devastated enemy troop formations Then in the fifteenth and sixteenth centuries in Europe archers used a new weapon the longbow oo000 FILE 0000000 Arrow Flights In ancient times people tried to design arrows that would fly straight They learned to attach tail feathers to the arrow These feathers or fletchings caused the arrow to spin as it flew That helped to make the arrow's line of flight straighter The study of objects that fly through the air is a branch of physics called aerodynamics Ooooooooooooooo The tail feathers at the back of an arrow help it to straighter fly
SCIENCE ooooo FILE FILE Catapults Like bows catapults use tension to fire projectiles A catapult is like a long lever Soldiers pulled down on the back to create tension in ropes at the front When the throwing arm was released tension whipped the end of the catapult forward and up Catapults could throw rocks or burning materials against or over the walls of enemy cities The longbow was a weapon about 6 feet 1 8 meters long Its additional length allowed it to produce even more force than normal bows Longbows took more skill to fire than regular bows because it was more difficult to pull back the bowstring Skilled archers could hit targets from more than 220 yards 200 m away Longbows killed many knights on horseback because the arrows pierced their armor The long arm of a catapult was pulled down to create tension in the crosspiece at the front When the tension was released the missile was launched into air the
The crossbow was far easier to use than the longbow Nearly anyone could go into battle and fire a crossbow toward the enemy without much training THE CROSSBOW Another common type of bow was the crossbow which was invented in China in about 700 BCE The crossbow consisted of a piece of wood with a short curved metal crosspiece at the front The crossbow had a mechanism to draw back the bowstring and to create tension in the ends of the crosspiece The user fired the crossbow by pulling a trigger The crossbow fired a bolt a short metal projectile with a pointed tip Unlike longbows soldiers needed little training to use a crossbow The weapon was also easier to fire while riding a horse The crossbow made it possible for commanders to move large numbers of unskilled soldiers who fought in huge masses By the thirteenth century the rise of mass armies marked the end of the era of knights mounted
