Menu English Ukrainian russian Home

Free technical library for hobbyists and professionals Free technical library


BIG ENCYCLOPEDIA FOR CHILDREN AND ADULTS
Free library / Directory / Big encyclopedia for children and adults

Where did the word school come from? Detailed answer

Big encyclopedia for children and adults

Directory / Big encyclopedia. Questions for quiz and self-education

Comments on the article Comments on the article

Did you know?

Where did the word school come from?

The word "school" originally originated in ancient Greece, but its meaning was completely different - "leisure, rest." However, this leisure was not idle - it meant philosophical conversations in their free time. Gradually, philosophers had regular students, and this concept began to denote the educational process. And when the need arose for special facilities for teaching children, they were also called schools in tribute to this tradition.

Authors: Jimmy Wales, Larry Sanger

 Random interesting fact from the Great Encyclopedia:

What makes a balloon rise up?

A hot air balloon is the simplest aeronautical apparatus. It usually consists of a light spherical or cylindrical "bag" made of paper, rubber, silk or rubberized material containing hot air, hydrogen or helium inside. A basket, or a gondola, in which passengers and goods are transported, can be attached to the ball using ropes or a net. The ball floats in the air for the same reason a fish swims in water. Each of them displaces from the water or air surrounding them, a mass greater than their own.

As long as the balloon and its gear weigh less than the displaced air, it will rise. If it loses some of the gas that lifts it and its mass increases, it will begin to fall. Hot air, hydrogen or helium is used as the lifting gas because they are all lighter than normal atmospheric air. The released balloon will rise until the weight of the displaced air is equal to its own.

In order to change the flight altitude, the aeronaut must either reduce his lifting forces in order to descend, or reduce his weight in order to ascend. To descend, he must release some gas through a valve at the top of the balloon. To rise higher, he must throw part of the cargo (ballast) overboard. Since neither ballast nor gas can be replenished during flight, it is obvious that the balloonist's ability to control the flight of the balloon is severely limited. At best, it can only rise and fall for a more or less short period of time, depending on the size of the ball.

Rising up, the ball falls into complete dependence on the winds. In flight, the balloon is almost impossible to direct. It can only sail with the wind, and for this reason it is of very little use as a vehicle. These days, hot air balloons are mainly used to explore the upper atmosphere. During the war, they were used as air observation posts, and they also built a kind of air barriers (something like air fences) to protect cities from bomber raids.

 Test your knowledge! Did you know...

▪ Why did people believe in the existence of witches?

▪ When were the first animal protection laws passed?

▪ What was the reason for Giordano Bruno's burning at the stake?

See other articles Section Big encyclopedia. Questions for quiz and self-education.

Read and write useful comments on this article.

<< Back

Latest news of science and technology, new electronics:

Machine for thinning flowers in gardens 02.05.2024

In modern agriculture, technological progress is developing aimed at increasing the efficiency of plant care processes. The innovative Florix flower thinning machine was presented in Italy, designed to optimize the harvesting stage. This tool is equipped with mobile arms, allowing it to be easily adapted to the needs of the garden. The operator can adjust the speed of the thin wires by controlling them from the tractor cab using a joystick. This approach significantly increases the efficiency of the flower thinning process, providing the possibility of individual adjustment to the specific conditions of the garden, as well as the variety and type of fruit grown in it. After testing the Florix machine for two years on various types of fruit, the results were very encouraging. Farmers such as Filiberto Montanari, who has used a Florix machine for several years, have reported a significant reduction in the time and labor required to thin flowers. ... >>

Advanced Infrared Microscope 02.05.2024

Microscopes play an important role in scientific research, allowing scientists to delve into structures and processes invisible to the eye. However, various microscopy methods have their limitations, and among them was the limitation of resolution when using the infrared range. But the latest achievements of Japanese researchers from the University of Tokyo open up new prospects for studying the microworld. Scientists from the University of Tokyo have unveiled a new microscope that will revolutionize the capabilities of infrared microscopy. This advanced instrument allows you to see the internal structures of living bacteria with amazing clarity on the nanometer scale. Typically, mid-infrared microscopes are limited by low resolution, but the latest development from Japanese researchers overcomes these limitations. According to scientists, the developed microscope allows creating images with a resolution of up to 120 nanometers, which is 30 times higher than the resolution of traditional microscopes. ... >>

Air trap for insects 01.05.2024

Agriculture is one of the key sectors of the economy, and pest control is an integral part of this process. A team of scientists from the Indian Council of Agricultural Research-Central Potato Research Institute (ICAR-CPRI), Shimla, has come up with an innovative solution to this problem - a wind-powered insect air trap. This device addresses the shortcomings of traditional pest control methods by providing real-time insect population data. The trap is powered entirely by wind energy, making it an environmentally friendly solution that requires no power. Its unique design allows monitoring of both harmful and beneficial insects, providing a complete overview of the population in any agricultural area. “By assessing target pests at the right time, we can take necessary measures to control both pests and diseases,” says Kapil ... >>

Random news from the Archive

Liquid laser that does not evaporate in air 14.02.2023

Scientists have created a cheap and easy to manage and use liquid laser.

Physicists at the University of Tsukuba in Japan have developed a tunable laser based on liquid droplets. Unlike previously created drop lasers, the new device does not require special conditions. The technology will help create cheap and flexible devices for optical communication.

For their development, the researchers used the "lotus effect". These plants are known for their ability to clear dust. Through microscopic tubercles on the surface of the leaf, water drops do not escape, but form almost perfect spheres that roll down, capturing dust particles with them.

Scientists have used a similar approach to create liquid droplets that can act like lasers while remaining stable until the moon. They used 1-ethyl-3-methylimidazolium tetrafluoroborate ionic liquid and mixed it with a dye. The researchers coated the quartz substrate for the "liquid laser" with fluorinated silica nanoparticles to make the surface repel liquids like a lotus leaf.

In a series of experiments, the scientists showed that when a prepared liquid is applied to a treated silicon substrate using a conventional commercial inkjet printer, tiny droplets form near-perfect spheres.

Such drops can remain stable for at least 30 days. The shape and resistance to evaporation allow the droplet to maintain optical resonance when excited by a laser pump source. And you can control the laser by blowing the surface with nitrogen gas: this shifts the laser peaks in the range from 645 to 662 nm, slightly deforming the shape of the droplets.

The researchers note that all modern droplet lasers require special conditions and cannot work in air because the droplets evaporate quickly. The presented development is the first cheap and affordable liquid laser.

Other interesting news:

▪ Lies change the brain

▪ Created diffraction gratings for the world's most powerful laser

▪ Music from the web

▪ openwork bike

▪ Sony IMX183CLK-J and IMX183CQJ-J image sensors

News feed of science and technology, new electronics

 

Interesting materials of the Free Technical Library:

▪ section of the site for the Musician. Selection of articles

▪ article Selected documents on emergency situations and disaster medicine in the Russian Federation. Basics of safe life

▪ article What disease did the French call Italian, and what did the Italians call French? Detailed answer

▪ Article Chief Director. Job description

▪ article Mobile phone charger repair. Encyclopedia of radio electronics and electrical engineering

▪ article Grounding and electrical safety protective measures. Mobile electrical installations. Encyclopedia of radio electronics and electrical engineering

Leave your comment on this article:

Name:


Email (optional):


A comment:





All languages ​​of this page

Home page | Library | Articles | Website map | Site Reviews

www.diagram.com.ua

www.diagram.com.ua
2000-2024