Transcript of Ancient Greek Mechanics and Medicine
Greek Medicine and Mechanics Levi Wetherington Ryan York Jared Howard Early Medicine Asclepius was the Greek god of healing. The Greeks prayed to Asclepius in times of sickness or plague. According to mythology, he learned the art of healing from his father Apollo. The temples of Asclepius were partly health spas and partly houses of worship where the sick visited in order to be healed. These temples were often built near mineral springs, and the people believed that bathing in or drinking the waters would cure their illnesses. Early Mechanics Often depicted as rough and dirty, Hephaestus was the Greek god of fire and metalworking. Hippocrates The first to take a scientific approach, Hippocrates taught medical students to observe each patient's symptoms and then select the appropriate treatment. His work later earned him the nickname "The Father of Medicine." The Hippocratic collection was a series of about seventy essays by unknown authors that are collectively referred to as the Hippocratic Collection because of their association with Hippocrates. These essays are the most significant source of information regarding medicine of ancient Greece. Hippocrates kept detailed case histories on each of his patients, establishing the practice of maintaining written records of diagnoses, treatments, and results. Hippocrates made each of his students take an oath, promising to practice medicine in an ethical way. Today, this is called the Hippocratic oath, and modern doctors must take a similar oath. Mental Illness Ancient peoples believed that mental illness was caused by witches or evil spirits. In ancient Greece, doctors recommended that mentally ill patients be kept in dark rooms. Asclepiades, considered the first shrink, took a new approach to mental illness and encouraged the ethical and humane treatment of the mentally ill. The Four Humors The ancient Greeks believed that sickness resulted when the body was out of balance. Greek physicians decided that four fluids, called humors, controlled human health. Each humor was associated with a different natural substance, moisture, temperature, body part, and season, and it was the job of the physician to balance the humors. Origins of Anatomy The word "anatomy" comes from the Greek word meaning "to cut up." In order to balance the humors, ancient Greek physicians would try to release excess humors. The practice of bleeding patients came from the ancient Greeks. Alcmaeon was the first person to dissect human bodies for scientific study. He wrote the first descriptions of the Eustachian tube inside the air and the optic nerve inside the eye. Herophilus, another Greek anatomy pioneer, established a medical school in Alexandria, Egypt. He is the author of the first detailed description of the human brain, and he recognized the brain as the source of human intelligence. The study of anatomy allowed the Greeks to do major surgery. They were able to amputate limbs, repair hernias, and remove stones from the bladder. The Syringe The early Greeks developed syringes made of animal bladders and thin metal pipes. Ctesibus was a Greek engineer from Alexandria who invented a new syringe around 280 B.C. This new syringe consisted of two pieces of metal: a piston, sliding valve, and hollow cylinder. The first description of Ctesibus's syringe is in a book called Pneumatics, written by Hero of Alexandria. Although a very learned society, most Greeks felt that mechanics was a lowly craft beneath their level of education, but that did not keep builders and engineers from creating impressive machines such as the screw, press, aeolipile, catapult, repeating catapult, water clock, an universal joint. The Screw and Press Greek engineers invented the sixth simple machine: an inclined plane wrapped helically around an axis, or a screw. The screw's main use other than fastening things was in an olive or grape press called a screw press. The screw press produced much more oil or juice than the original press which was operated by winches. In the first century a Greek inventor named Hero improved the screw press by removing the levers. Hero Besides the improved screw press Hero invented many other machines. He invented the ancient equivalent of the water hose with a complex system of valves, chambers, and parts for water flow. Hero also invented the aeolipile, a simple steam engine. Another invention of Hero's was a small windmill used to blow air into a toy organ. One remarkable invention was a miniature moving theater which was powered by weights, strings, and rotating drums. The negative side to Hero was that he cared little for practical applications so his devices were never used in real life. Ancient Research and Development Dionysius the Elder ruled Syracuse on the island of Sicily from 405 to 367 B.C. A legend says he oversaw research in weaponry for the coming war with Carthage in Africa. He gave small teams parts of a larger assignment and paid cash bonuses for a job well done. These teams invented the catapult. The accuracy of this legend is actually debatable as King Uzziah in the Hebrew Bible was recorded using catapults in sieges. Regardless of the origin, catapults were used in the war with Carthage. Engineers The ancient Greeks quit looking down on engineers, and began relying on them and mathematicians to design and build accurate catapults. The Greek army trained an elite group of soldiers to operate catapults, and were not easily replaced if killed in battle. Innovations Although it never caught on due to its short range and the waste of ammunition, Dionysius' repeating catapult marked a huge advancement in ancient mechanics because it was the first time flat-linked chains and universal joints emerged. Full transcript
The flat-linked chain, similar to a bicycle chain, was used to turn a chamber to drop arrows into firing position. The universal joint was used to quickly aim the catapult in any direction, and is currently found in modern machines such as cars. Warfare Catapults were used to siege cities by repeatedly firing on city walls until they came down. Because of this, cities could be taken over within a few days rather than years, as it had been in the past. Military engineer Philo of Byzantium calculated city walls would need to be 15 feet thick to survive catapult attacks.
Feared because of the terror imposed by the day and night attacks, soldiers and citizens often ran at the sight of catapults, thus developing the use of psychological warfare by the Greeks.
Before catapults, ships against the Greeks were usually rammed and boarded for battle. Because of the danger and cost of this technique, Greek naval ships began being equipped with catapults which allowed for long-range attacks. Archimedes Most famous for his discovery of buoyancy during the 200s B.C., Archimedes was a great mathematician, inventor, and engineer. Arguably Archimedes' biggest success, however, was laying the foundation for calculus, and discovering how to find the area and volume of many shapes which he all wrote down in his book "The Method."
Archimedes is credited for the invention of the compound pulley. The compound pulley, or block and tackle, is a combination of a fixed pulley with moveable pulleys which allowed for a mechanical advantage of changing the direction of force and increasing the force of a person's pull. Archimedes also proved the law of levers that explained how a lever could lift loads of any weight depending on the position of the fulcrum. Archimedes proved his machines and laws when he alone lifted a loaded ship of men and cargo with a system of compound pulleys. Archimedes' War Machines Connected to the sea, the city of Syracuse was attacked in 214 B.C. by Romans. The siege, however, was a failed attempt when Archimedes designed cranes equipped with a system of ropes and pulleys and powered by oxen. These cranes were used to lift boulders and led balls weighing up to to 600 pounds, swivel over city walls, and drop huge objects on approaching Roman ships.
A crane of very similar structure was also used to defend Syracuse. This weapon was called the Claws of Archimedes, a crane with a rope and hook attached to the end used to grab Roman ships by the hull and lift them from the water.
Although the Greek writer Plutarch lived many generations after Archimedes, he wrote of his inventions often and described the scene of the Roman ships being shaken free of soldiers and smashed from great heights. Gears Gears are machines that transfer motion from one turning shaft to another turning shaft. Unknown of their origin or inventor, gears were originally wooden wheels fit together with small spokes. Ancient Greek engineers used gears to transfer motion, and change the direction, force and speed of motion.
Written in the 300s or 200s B.C. by an unknown author, the book "Mechanica" is the oldest known engineering textbook, and gives the first written description of gears and gear trains.