Canada and the World
Current Events with a Canadian Perspective
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08 December 2010
Science Timeline Part Two
From thoughts about atoms in Ancient Greece
to the brilliant mathematics of Archimedes
in the third century BCE
In the 5th century BCE, Leucippus said that every event in the world had a natural cause. This contradicted the popular belief of the time that such events as volcanic eruptions or thunderstorms were the handiwork of the gods.
Thinking about Small Particles
One of Leucippus’s students was Democritus (left). He speculated that matter was
composed of tiny particles that were so small they could not be divided. He called
these particles “atoms” from a Greek word meaning “indivisible.”
Of course, Democritus, who lived from 460 BCE to 370 BCE was only guessing, but it was a pretty darn good guess. It would be more than 2,000 years before particle physicists were able to prove the existence of atoms.
While Democritus was thinking about tiny particles, other Greek scholars were working on other branches of science.
This was a golden age of discovery. The philosopher and scientist Theophrastus became the founder of botany and the astronomer Hipparchus developed trigonometry.
Medicine Gets a Patriarch
Hippocrates (460 BCE – 377 BCE) is called the father of medicine. Until he came along,
diseases were thought to be caused by gods in a grumpy mood. So, cures were based
on praying and casting spells to cheer the gods up a bit.
Hippocrates came up with the idea of examining a patient and recording symptoms. He kept notes about his successes and failures; the backbone of proper scientific research.
However, Hippocrates was a bit off the mark when he put forward his theory that disease was caused by an imbalance of the four humors (or fluids) of the body: blood, phlegm, bile, and black bile.
The anatomists and physicians Herophilus and Erasistratus based anatomy and physiology on dissection. They were both particularly interested in the brain and developed a rudimentary understanding of its function.
Herophilus and Erasistratus did their cutting up of bodies at the Museum of Alexandria, in Egypt. It was a poor location to pick. The Egyptians believed the human body must be kept intact for it to enjoy an afterlife.
When they found out the two Greek scientists were carving up their dead loved ones they got rather annoyed. All dissection at the Museum was halted. The study of the human body ceased for more than fifteen centuries as a result.
Archimedes: a Great Mathematician
Another Greek scholar, Archimedes (298 BCE – 212 BCE), developed fundamental notions about mechanics and hydrostatics (the behaviour of liquids). He found ways of calculating the area and volume of spheres and other curved surfaces.
His methods anticipated integral calculus 2,000 years before it was “invented” by Sir Isaac Newton and Gottfried Wilhelm von Leibniz.
But, for so great a scientific mind it’s a little humiliating that everybody remembers him for yelling “Eureka!” leaping out of his bathtub, and running naked into the street to announce a new discovery. Sorry! But, it didn’t happen. There is absolutely no credible evidence that Archimedes ran around wearing nothing but a grin and shouting “I have it.”
He did discover the physical law of buoyancy; still known today as Archimedes’ Principle. An explanation of which that: any body completely or partially submerged in a fluid (gas or liquid) at rest is acted upon by an upward, or buoyant, force the magnitude of which is equal to the weight of the fluid displaced by the body. So, a ship that is launched sinks until the weight of the water it displaces is just equal to its own weight.
Ray Jones
Archimedes invented a screw device for lifting water out of a river or lake to irrigate fields. The Archimedes Screw Principle is still used today for irrigation, but here in Wales the concept is applied in reverse to generate electricity.
People had used levers since long before recorded time, but it was Archimedes who figured out why a lever could move heavy weights. So what! Why so much fuss over working out the mathematics of something that had been in practical use for thousands of years?
The point is that understanding the principle helps development. Knowing how and why something works means its principle can be applied elsewhere. The device can be studied and improved. With a theory to explain practice, advances are speeded up enormously.
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747 BCE
Mesopotamians begin keeping a continuous record of lunar and solar eclipses.
530 BCE
Pythagoras, comes up with a “general formula for finding two square numbers the sum
of which is also a square, namely (if m is any odd number), m2+{1/2(m2-
This only one of many Pythagorean discoveries that would cause misery to countless later generations of schoolchildren.
About 470 BCE
Zeno of Elea devised a number of tricky statements that are designed to tie philosopher’s minds in knots.
His most famous paradox is the one which swift-
440 BCE
Anaxagoras of Athens states that the Moon shines because of light reflected from the Sun.
Somewhere between 360 BCE and 350 BCE
Chinese astronomers were the first to record a supernova (exploding star), although at the time they didn’t know what it was. Fifty years later, Shih Shen, Gan De, and Wu Xien compiled star maps that would be used for hundreds of years. And, in 230 BCE, Chinese skywatchers were the first to record Halley’s Comet.
250 BCE
The first recorded use of zero is attributed to the Babylonians. Kristen McQuillin writes in a Brief History of Zero (January 10, 2004) that “the Mayans, halfway around the world in Central America, independently invented zero in the fourth century CE. The final independent invention of zero in India was long debated by scholars, but seems to be set around the middle of the fifth century.”
About 240 BCE Eratosthenes of Cyrene used geometry to measure the circumference of the Earth. His calculation was 45,600 kilometres, close to the actual figure of 40,075 km. It wasn’t until 1736 that a more accurate measurement was made.
200 BCE
Concrete is used for the first time to build the town of Palestrina near Rome
85 BCE
No doubt waterwheels were invented earlier, but the first known mention of one is in a poem written in 85 BC.
“Anatomy” comes from Greek words meaning “to cut up.”
THE END OF SCIENCE
-
By the 3rd century BCE, the Roman Empire was growing and this spelled doom for science. The Romans were brilliant militarists, builders, and governors, but they were poor theoretical scientists. They had crushed the Greeks by 146 BCE. The Roman Empire itself was trashed in 476 AD, and Europe was plunged into what some call the Dark Ages.