Archimedes and his discoveries briefly. Archimedes' law: the history of discovery and the essence of the phenomenon for dummies. Archimedes - life and scientific works

Insects don't have lungs. Main respiratory system they have tracheae. Insect tracheae are communicating air tubes that open outward on the sides of the body with spiracles. The finest branches of the trachea - tracheoles - permeate the entire body, braiding organs and even penetrating inside some cells. Thus, oxygen is delivered with air directly to the place of its consumption in the cells of the body, and gas exchange is ensured without the participation of the circulatory system.

Many insects living in water (aquatic beetles and bugs, larvae and pupae of mosquitoes, etc.) must rise to the surface from time to time to capture air, i.e. they also breathe air. The larvae of mosquitoes, weevils and some other insects, for the time of renewal of the air supply in the tracheal system, are "suspended" from below to the surface film of water with the help of non-wettable greasy hairs.

And aquatic beetles - hydrophiles (Hydrophilidae), swimmers (Dytiscidae) and bugs, for example, smoothies (Notonectidae) - breathing near the surface, carry an additional supply of air with them under the water under the elytra.

In insect larvae living in water, in moist soil and in plant tissues, skin respiration also plays an important role.

The larvae of mayflies, stoneflies, caddisflies and other insects, well adapted to life in water, do not have open spiracles. Oxygen in them penetrates through the surface of all parts of the body where the covers are thin enough, especially through the surface of leaf-shaped outgrowths pierced by a network of blindly ending tracheae. In larvae of mosquitoes (Chironomus), respiration is also cutaneous, with the entire surface of the body.

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Archimedes is an ancient Greek inventor, mathematician, mechanic and engineer who lived in the 3rd century BC (287 - 212 BC).

Not much is known about his life, since almost all the authors who transmitted his biography lived much later.

As a result, the biography of Archimedes is full of legends, some of which have become very popular.

Biography of Archimedes briefly

Archimedes was born in Syracuse - this is one of the first Greek colonies on the island of Sicily. It is possible that his father was the famous Phidias, an astronomer and mathematician. Putarch also reports that Archimedes was a close relative of Hiero II, tyrant of Syracuse.

Being related to such celebrities, Archimedes was able to receive an excellent education: he studied in Alexandria, which at that time was famous as a center of learning. After training, he returned to his homeland and could fully engage in science, as he did not need funds.

Inventions of Archimedes

• Archimedean screw, or auger - serves to lift and transport goods, scoop out water. This device is still used today (for example, in Egypt).
• Different types of cranes based on pulleys and levers.
• The Celestial Sphere is the world's first planetarium, with the help of which it was possible to observe the movement of the sun, moon and five planets known at that time.
• A number close to the number P is the so-called "Archimedean number": 3 1/7; Archimedes himself indicated the accuracy of the approximation of this number. To solve this problem, he built a circle into 96-gons inscribed and circumscribed around it, the sides of which he then measured.
• Discovery of the fundamental law of physics in general and hydrostatics in particular. This law is named after him and consists in the ratio of the buoyancy force, volume and weight of a body immersed in a liquid.
• Being the first theoretician of mechanics, Archimedes introduced into it thought experiments. The first such experiments were his proofs of the law of the lever and the law of Archimedes.

Defense of Syracuse

In 212, the Romans besieged Syracuse. But they could not capture the city for a long time. Legends say that a long defense was made possible thanks to one resident of the city - Archimedes. He built throwing machines that destroyed the Roman army with heavy shells, and cranes that lifted enemy ships and sank them.

Archimedean screw photo

It is also reported how Archimedes, using mirrors and shields polished to a shine, set fire to Roman ships, focusing on them. Sun rays. There is an opinion that the ships were set on fire by burning shells thrown with the help of the same throwing machines, and the focused sun's rays served only as an aim.

blocks and levers of Archimedes photo

Mentions of this weapon are just legends, but in last years experiments were carried out to establish whether these inventions could actually exist. In 2005, scientists reproduced cranes that turned out to be quite efficient. And in 1973, the Greek scientist Ioannis Sakkas set fire to a plywood model of a Roman ship using a combination of mirrors.

inventions of Archimedes defense of Syracuse photo

Nevertheless, scientists continue to doubt the existence of "mirror" weapons at Syracuse, since none of the ancient authors mentions it; information about him appeared only in early middle ages- from the author of the VI century Anthimius of Tralles. Despite a heroic - and ingenious - defense, Syracuse was finally subdued, and Archimedes died the same year.

There are many versions of the death of a scientist, but most of them agree that Archimedes was killed by a Roman soldier when he was sitting near his house and pondering over the drawings.

We have outlined in general the life of the inventor, his scientific and inventive achievements. In this article we will try to list the inventions of Archimedes with a more detailed explanation.

Here is a list of inventions of Archimedes for quick navigation:

Lever Upgrade

"Be at my disposal another land to which
I could get up, I would move ours.
(c) Archimedes

Archimedes, of course, was not the one who invented the lever, since this is a fairly simple device, but he was the one who theoretically described the principles of its work and, understanding these principles, was able to develop and improve it. He also explained the principle of multistage transmission.

In his work On the Equilibrium of Planes, or the Centers of Gravity of Planes, Archimedes writes the following:

Bodies of the same weight, which are equidistant from the center, will be in equilibrium, but if the distance of one of them is changed, then the balance will be disturbed in favor of the body that is located at a more distant distance from the center.
If we take two bodies of the same weight, which are equidistant from the center, and add additional weight to one of them, then the balance will be disturbed in favor of the greater weight.

Lever Principle and Mathematical Relationship

Worm-gear

Many historians believe that Archimedes also managed to invent the worm gear. Considering that Archimedes invented the screw that lifts water, there is no doubt that he could have guessed before this invention. Later he described a screw with a special slider that slid along the screw along its thread. But for the era of Heron, this mechanism seems outdated, since screws and nuts already existed in his time. It is possible that Heron described exactly the invention of Archimedes by reading some of his writings that have not come down to us.

Connecting pulley

A pulley is a wheel along which a rope or chain can be installed. A person pulling on one end of a rope can lift a weight on the other end of the rope. The pulley wheel acts as a fulcrum, reducing the force needed to lift the load. Archimedes invented a whole system of pulleys to lift and move loads

The pulley system can be further complicated in order to obtain a greater gain in strength.

The successive complication of the pulley system and calculations for them show that it is possible to achieve a reduction in the required force by a factor of 4.

King Hieron, having heard that Archimedes could move any heavy objects, did not believe him and asked him to prove it. The timing was good, because in Syracuse there was just a problem with a huge ship (the ship was named after the city), which could not be taken out of the harbor. It should be noted that the ship was stunningly beautiful and reached a length of 55 meters. According to Plutarch, Archimedes managed to get the ship out of the harbor of Syracuse using a complex system of levers and pulleys.

Archimedes screw

"Eureka!"
(c) Archimedes

Also, this invention is sometimes called "Archimedes' snail" or a water screw. The device is designed to lift water, for example, to irrigate fields. The Archimedes screw is a spiral that rotates inside the pipe, transferring water upwards on the screw blades. The rotation of the helix was set by rotating a special handle from above. The handle itself could be rotated by both a person and cattle or horses, and in later times a water wheel or a windmill could be used. In addition to water, granular materials such as ash or sand can be transported to the top with a screw.

Perhaps this is one of the oldest devices known for lifting water. The screw is still used today in small power plants and even on farms. Since 1980, eight Archimedes screws with a diameter of about 3.6 meters have been used in the state of Texas in the USA to combat stormwater. The screw is driven by a 551 kilowatt engine and can pump out up to 500,000 liters of water per minute.

Archimedes screw used in Texas in the USA

The main advantage of the Archimedes screw is that the ingress of debris into the mechanism does not lead to disruption of the device. For example, with the help of a screw, you can even lift the fish along with the water, while the screw will continue to work.

A detailed explanation of the working principle of the Archimedes screw:

A huge Archimedes screw installed at a hydroelectric power plant:

And in this video, the Archimedes screw was made from Lego:

Iron hand or claw of Archimedes

The claw of Archimedes was a weapon that the inventor invented during the siege of his hometown Syracuse. The city had to be defended from the fleet of the Roman Empire, so it was necessary to develop effective methods to sink the fleet directly from the fortress walls.

We do not know the exact design of the device, but we have a rough idea of ​​the principles on which it was based. If you carefully read about the invention of pulleys and the lever, then it will not be difficult to understand the principle of the claw.

The principle of operation of the claw of Archimedes

The claw of Archimedes was a system of pulleys, ropes and beams. At one end of the rope was a hook that was thrown onto an enemy ship and hooked under the belly of the ship. On the reverse side the ropes behind the wall were already at the ready, the bulls and the people who began to pull the rope. As a result, multi-ton ships were turned over or thrown onto stones, scattering the enemy fleet and crew around the walls.

The pitiful Roman fleet is nothing against the mind of Archimedes!

In our time, as many as two groups of people have tried to build the claw of Archimedes and flood the ship. We suggest that you look at both attempts and make sure that the device was operational.

Catapults, ballistae and scorpions

Painting depicting the siege of Syracuse.

During the siege of Syracuse, Archimedes built artillery that could cover a range of ranges. While the attacking ships were at a great distance, he fired from catapults and ballistas, throwing huge stones and logs at the enemy ships. If the ships approached the fortress walls for an assault, then they were met by a whole stream of arrows from "scorpions" (small catapults throwing steel darts). By the way, it is worth noting that it was Archimedes who proposed to make loopholes, which was an innovation in the fortification of that time. From small openings, archers successfully fired at the advancing Romans. Thus, the Romans could not approach the walls of Syracuse, and if they did, they suffered huge losses.

True, from a historical point of view, Archimedes was not the one who first invented all these structures, but he clearly made his own modifications to them (for example, improved accuracy) and successfully used them for defense.

Igniting mirrors

Well, this invention for its time definitely amazes any fantasy. Archimedes thought of burning enemy ships with the help of the sun. In some articles, this invention is even called "death rays". How was it organized?

The Romans stood near the city with their 60 quinqueremes. Archimedes was educated enough in terms of optics to make convex mirrors. Presumably it was not a single mirror, but a whole system of mirrors heading to one place to focus the rays. The system most likely consisted of 24 mirrors, which were combined into one frame and rotated with the help of hinges, changing the angles of rotation.

How mirrors work

In fact, it is not completely clear why Archimedes used the mirrors. It is likely that he did not burn the fleet with them, but only blinded the archers on the ships. There is also a version according to which, with the help of catapults, special shells were thrown onto ships, which were then set on fire with the help of mirrors, so one might think that these mirrors are burning ships. And there is also a version that mirrors were used only for pointing catapults.

In 1973, the Greek scientist Ionnis Sakkas became interested in the possibility of burning the fleet with the help of mirrors, so he set up an experiment. 60 Greek sailors held 70 mirrors, each of which had a copper coating and measured 1.5 meters by 1 meter. The mirrors were directed to the plywood model of the ship, 50 meters away. The mirrors calmly set fire to the model, which proved the practical possibility of setting fire to the fleet with the help of mirrors.

In 2005, the MythBusters repeated the experience, albeit in a slightly different way. They used convex mirrors in the amount of 500 pieces and with a smaller area. They managed to burn the sail on the layout only after 1 hour, so their experiment showed that burning the fleet with mirrors is not very convincing.

Odometer

Odometer of Archimedes

Aristotle creates the odometer around 330 BC. This device made it possible to measure the distance traveled, which was indispensable when creating maps or when building large structures.

The principle of operation of the odometer is simple. The wheels turn and drive two gears. After certain distances, the gears release a small ball that falls into a special container. At the end of the path, you can count the balls and find out which path you have traveled.

As a result, the Romans took Syracuse through bribery. Traitors opened the gates for them, and Archimedes was killed. Cicero later described the return of the Romans to Rome, saying that among the spoils of war was the beautiful mechanical planetarium invented by Archimedes. The planetarium demonstrated the movement of the five planets and eclipses. This reconstruction showed the daily movement of stars around the Earth, the eclipses of the Sun and Moon and their movement along the ecliptic.