The ray of Archimedes

February 28, 2012 21:56

Mirrors of ArchimedesThe ancient Greek scientist Archimedes made so many discoveries in mathematics, astronomy and mechanics, that in the last century, a lot of myths about his accomplishments …

Everyone knows the story of how Archimedes discovered the law named after himself, jumped out of the bath without a tunic with a cry of "Eureka!" Is Sage running down the street without clothes, today is hard to say. But the discoveries have been documented, it is not disputed.
But the legend of the burning of the Roman fleet is somewhat different.
For sure to find out whether Archimedes burnt the Roman fleet or is it only an invention of historians, is now impossible.

What are silent witnesses

Reached us several descriptions storming of Syracuse, in which Archimedes, according to legend, the Romans burned the ships. In 212 BC, during the Second Punic War, the Romans laid siege to the Greek city of Syracuse. Enemy ships were from the shore at a distance of 300 cubits (about 150 meters), and because Archimedes constructed a catapult firing stone balls and incendiary shells, could not hurt them.
Archimedes then ordered the soldiers to a high gloss polished shields and take the mirror and then focus the sun's rays on Roman ships. The Warriors did as instructed scientist and wooden trireme — the so-called military Roman ships — immediately erupted into flames.
According to another version, the women helped Archimedes of Syracuse. They call him up to the ramparts with polished to a high gloss copper utensils, sending sunlight on Roman ships.
A third theory scientist has built a large machine that included a system of mirrors. In the center was a large hexagonal mirror, probably consisting of a number of sections. Next to it were attached quadrangular. System is regulated by a chain mechanism. Turning the lever unit focused solar radiation at different distances. This mechanism was set on fire several vehicles. Then the fire began to spread to other vessels. Romans had to retreat.
Unfortunately, in the chronicles of the time there is no word on the use of fire in this battle. It was only 400 years after the battle of writers and scholars of the time in his writings and then casually mention of her as the fact known to all. Then there are the first attempts to test how it all happened.

Death of Archimedes

Who lived in the VI century BC. e. mathematician, architect and sculptor Anfimov (who built the famous temple in Constantinople Sofia) created a system of twenty-four mirrors. Researchers used an unknown source, that outlines the mirror of Archimedes. Confirmation of combat efficiency of the mirror was held back: his house burned by Anfimov long pester him neighbor.
Attempts such reconstructions were made and after Anfimov, but the solution is not dramatically different — yes, in general, and could differ materially, as the principle Anfimov found the right.

The famous philosopher and mathematician Rene Descartes in his "Dioptrics" has proved that to reduce the sun's rays to a point impossible. "Only people who are not too well-versed in optics, convinced of the reality of many tales, these mirrors in which Archimedes allegedly burned the ships from a distance, or were extremely large, or, more likely, does not exist" — wrote the famous French scientist.
After calculations and conclusions of Descartes story mirrors and Navy were considered a myth, and reputation, if not of Archimedes, the ray-mongers, was dealt a serious blow. However, a hundred or so years, in 1747, Descartes compatriot Georges-Louis Leclerc de Buffon made a bold assumption that the amount of heat is proportional to the amount of scattered light. It followed that, even if the mirror is not too large, the heat may be enough to set fire to the wood.
In 1747, he built a system consisting of 128 flat mirrors. George not only ignited so tarred board at a distance of fifty yards, but was able to melt the silver and lead.
Experiments Buffon rehabilitated Archimedes — was no doubt that such a system could be set up and in the II century AD But the work of the Frenchman eventually forgotten, and the question was still open.

Modern pyromaniac

MIT scientists conduct experiments, confirming the discovery of Archimedes

Create hyperboloid Archimedes tried and modern scientists. So, in 1973, Ioannis Sakas, Greek mechanical engineer, and scored 70 assistants, placed them on the bay 91h50 mirrors, see the engineering team assistants lifted the mirror, focusing sunbeams on the boat with the resin. Finally, when the sun's rays are aligned at one point, the boat began to smoke for a few minutes broke!
And in 2005, had a similar experience of professors and students at the Massachusetts Institute of Technology.
The leaders of the experiment, studying the ancient sources, we decided to act according to the simplest option.
They bought 129 square mirror tiles with a party of about 30 cm, and without relying on the diligence of the students to set them on a semi-circular design team at a distance of about 50 meters away from the three-meter layout of the ship. One of the mirrors were papered with adhesive tape so that the reflected light had to go to a tilted cross.
According to the plan, he served as an eye. Putting an end to the galley cabinet, mirrors gradually consolidated.
Cope with targeting 129 mirrors needed for ten minutes, otherwise it would take the sun away.
Installation debugged few people. In addition, light clouds covered the sky, which somewhat reduces the light output. Finally, when the sun came out in full, the coordinators from the mirrors pulled off the curtains.
On the bow appeared bright spot of light. After a few minutes seemed to light smoke, traces charring, and then flash and open flame. Layout of the ship flared like a sliver. As measured by reflected sunlight spot temperature reached 593 ° Celsius.
Later, the experiment was repeated already in the water — and over the ship broke.
It turns out that Archimedes could really use a system of mirrors to set fire to Roman ships.

In a laser sight

Laser gun Archimedes

According to Italian researchers, mirror system still existed. But its effect on actually was not quite so, as is commonly believed. Their light blinded oncoming enemy ships and then really broke out like candles. But not a "laser" was the reason, but all the same Greek fire — incendiary mixture of resin, sulfur and saltpeter, is not yet known if the Romans. "Lighters" hurled from catapults on the city wall remarkably accurate and efficient.
According to the Italians, the huge bronze discs, blinding enemies reflected sunlight, served … telescopic sights. More precisely, it can be called a "laser sight". As a thriller about a hired assassin.
The killer, sitting a few hundred yards from his victim, brings her red laser point … and pulls the trigger.
To develop such a system in antiquity, Archimedes was necessary to know two things: flight-shot from a catapult, and the optimal distance at which the human eye can distinguish between light disc, cast by the mirror on the sail. The first was perfectly well known to any soldier, the second was easy to determine experimentally the streets of the city. Next Archimedes constructed thrower in which the shooter took his bow at a time when there was a combination of axle shafts in the sunbeams. All weapons have been calculated taking into account the curvature of the arrow's flight to a distance of 300 cubits. When the fleet of Marcellus close to this distance from the mirrors fell off covers, throwers have put guns on the "target designation," broke arrowheads and rattled pull the string …
Here, too, would like to quote the words of Plutarch: "Archimedes was so proud to science, what about those of his discoveries, through which he gained fame … he has not left any writings." This is not quite accurate, but many works of Archimedes, we really do not know, but because there is no guarantee that in the future there will still some mystery of the great scientist.


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