Secondary education and schools

A lens is a transparent object, most often made of glass. Its main feature is that it is able to refract sunlight. Let us consider how images are constructed in a thin lens. The article will provide the formula and drawings. Last modified: 2025-01-23 12:01

The Republic of Kazakhstan is one of the most promising developing countries in Central Asia. It is located in the heart of the continent and ranks 9th in the world in terms of area. This is a state with a rich history, picturesque landscapes, interesting culture and inexhaustible natural resources. A list of regions of Kazakhstan and a description of each of them can be found later in the article. Last modified: 2025-01-23 12:01

The number of rivers in Kazakhstan exceeds 39 thousand. They are unevenly distributed over the territory, since in Kazakhstan there are desert arid lands, and there are mountains and hills. Last modified: 2025-01-23 12:01

The Ishim Plain is sometimes called the Ishim Steppe in Russia. And in Kazakhstan - the North Kazakh Plain. It is composed of lacustrine-alluvial deposits, as it is located between two large water arteries: the Tobol and the Irtysh. Last modified: 2025-01-23 12:01

Danube is an international river, it is interesting because it flows through many European states, it hosts capitals and large cities. It is the longest river in the European Union. This river was mentioned in ancient Greek and Roman sources. In the writings of the historian Herodotus, the ancient name of the Danube is mentioned. Last modified: 2025-01-23 12:01

Many representatives of the animal world have external digestion, it is not a rare occurrence. It involves the digestion of food not in the intestines or stomach, but outside, that is, when digestive juices are released into the external environment. Last modified: 2025-01-23 12:01

The Andes are one of the most beautiful mountain systems on the planet. And at the same time - this is the longest mountain range in the world, the length of the Andes mountains is 9 thousand kilometers. They stretched through several large states and climatic zones, the nature here is very diverse and unique. Last modified: 2025-01-23 12:01

Reservoirs on the planet have a different origin. Water, glaciers, the earth's crust and wind are involved in their creation. Signs of a lake that appeared in this way can be different. Last modified: 2025-01-23 12:01

The Novosibirsk Islands are an archipelago located in the Arctic Ocean. It is part of the territory of Russia, but has not yet been mastered, but only studied. This article will go into more detail about the Sannikov Strait, named after one of its first explorers. Last modified: 2025-01-23 12:01

Murmansk… Almost all Russians associate this name with something distant, northern and cold. But not everyone will be able to accurately show the location of this city on the map. Where is it located? What is the longitude and latitude of Murmansk? You will find answers to these questions in our article. Last modified: 2025-01-23 12:01

The ocean current is the most important link in the well-oiled mechanism of the entire World Ocean. To date, there are dozens of large flows of water masses. Last modified: 2025-01-23 12:01

The word "desert" alone evokes the appropriate associations for us. This space, which is almost completely devoid of flora, has a very specific fauna, and is also located in a zone of very strong winds and monsoons. The desert zone is about 20% of the entire land mass of our planet. Last modified: 2025-01-23 12:01

This is a topic worthy of a separate monograph. The coalition can play both a positive and a negative role for those who join it. It can bring victory or, conversely, force them to solve not only their own problems, but also the problems of their allies. It can help to withstand a strong enemy, or it can deprive sovereignty. Last modified: 2025-01-23 12:01

One of the foundations of current knowledge is stored in the familiar word "geometry". Most remember him from school and associate complex figures, numbers and endless proofs with him, while some work with geometry on a daily basis. Be that as it may, this science laid the foundation for bold discoveries with centimeter-accurate calculations. Last modified: 2025-01-23 12:01

Among the many quotes of historical figures and political figures, one of the most famous is this: "History does not tolerate the subjunctive mood." Many attribute its authorship to Joseph Stalin, which is confirmed in writing. But he was not the first to use it, and not in the exact wording. It is largely the result of adaptation in translation from German and its modernisation. But the meaning of the expression should be extremely clear to each of its readers. Last modified: 2025-01-23 12:01

Every year, dodgy graduates try to find a way to sneak a phone through a metal detector on the exam, and every year, despite the constant tightening of exam rules, they succeed. Last modified: 2025-01-23 12:01

The final written work is a mandatory exam, the passage of which gives the future applicant the opportunity to pass the exam. The coveted “test” in writing is admission to exams in other subjects. So what does the ideal job look like? Find out in the article. Last modified: 2025-01-23 12:01

The Messoyakhskoye field was discovered in the 1980s, but it was impossible to start mining at that time. The level of scientific and technological progress was insufficient, and it was impossible to increase it during the period of perestroika that had begun. Last modified: 2025-01-23 12:01

Recently, the word "harassment" can be found more and more often on the Internet. Many people who are not familiar with English terminology ask the same question: "What does this word mean?" If you are one of those people, don't worry! The meaning of the word "harassment" is just like 5 kopecks, and even a person who is not a linguist will understand it. Last modified: 2025-01-23 12:01

One of the important laws of light wave propagation in transparent substances is the law of refraction, formulated at the beginning of the 17th century by the Dutchman Snell. The parameters that appear in the mathematical formulation of the phenomenon of refraction are the indices and angles of refraction. This article discusses how light rays behave when passing through the surface of different media. Last modified: 2025-01-23 12:01

Images in lenses, the operation of instruments such as microscopes and telescopes, the rainbow phenomenon and the deceptive perception of the depth of a body of water are all examples of the phenomenon of refraction of light. The laws describing this phenomenon are discussed in this article. Last modified: 2025-01-23 12:01

Table s alt has been known to mankind for several thousand years, in ancient times the substance was considered "white gold". Geologists call the mineral, which includes sodium chloride, "halite". Its composition reflects the formula of table s alt - NaCl. In industry, the outdated name for this compound is often used - "sodium chloride". Last modified: 2025-01-23 12:01

Feeding algae is a typical example of how they obtain energy for life. For example, plants use solar energy, and animals eat plants that are eaten by other predators. The food chain is a sequence of who eats whom in an ecosystem (biological community) to acquire nutrients and the energy that supports life. Last modified: 2025-01-23 12:01

Very often throughout the world you can find numerous different accumulations of water. As a rule, they are formed in depressions of the earth's surface. Therefore, the questions arise: “Reservoirs - what is it? What is the cause of their occurrence? In order to answer them, you need to get acquainted with such a science as hydrology. Last modified: 2025-01-23 12:01

Natural reservoirs filled with fresh water are becoming increasingly valuable for humanity over time, since vigorous economic activity causes too much damage to the environment. Last modified: 2025-01-23 12:01

Today, robotics classes are becoming very popular. For schoolchildren, such lessons help form and develop critical thinking, learn how to creatively approach the process of solving problems of various levels of complexity, and also gain teamwork skills. Last modified: 2025-01-23 12:01

All the diversity of organisms on our planet is inextricably linked. There is no such creature that could exist in isolation from everyone, strictly individually. Last modified: 2025-01-23 12:01

Hydrogen oxide - what is this compound? Physical and chemical properties of water, distribution in nature, biological role. Hydrogen and its importance for the formation of water. Last modified: 2025-01-23 12:01

The function of the root cap, its structure. Calyptra cells, plant geotropism. Types and types of roots, functions of the plant root. Types of root systems. Root zones: table. Last modified: 2025-01-23 12:01

Single-celled fungi: general characteristics, representatives. Features of the structure, reproduction, lifestyle. Significance in human life and role in nature. Classification of unicellular fungi. Last modified: 2025-01-23 12:01

Physical and chemical properties of natural gas, its production and deposits. Types of natural gas, composition and quality. Main areas of natural gas use. Last modified: 2025-01-23 12:01

Smooth muscle tissue: structural features, properties, main functions. Myocytes of smooth muscles, their structure, composition and properties. Classification of the muscles of the animal body. Origin and regeneration of smooth muscles, localization in the body. Last modified: 2025-01-23 12:01

A very important cycle of subjects in the framework of the school curriculum is natural science. After all, it is he who gives an idea of nature, its phenomena, living beings, their relationship with man. Geography, biology, physics and chemistry are the foundation that allows children to enter into life, begin to understand the things that are happening around, navigate and manage them. Last modified: 2025-01-23 12:01

Origin of natural gas, its characteristics. Composition, properties, features. Industrial production and world reserves of this product. Deposits in Russia and the world. Last modified: 2025-01-23 12:01

Polymers and materials made from them, household items, equipment are an important part of industry and human life in general. Natural resources, unfortunately, have been greatly depleted during their use. Therefore, people had to learn how to synthesize artificial materials that have a number of important technical characteristics. Last modified: 2025-01-23 12:01

Salair Ridge - part of the region of Southern Siberia, a low-mountain upland. It is a spur of the Kuznetsk Alatau. The ridge begins in the region of the river. Neni, in its upper reaches. Then it descends in a northwestern direction between the rivers Chumysh and Kondoma, flows along the water flow of the Ob. Last modified: 2025-01-23 12:01

The largest river in the Chelyabinsk region is considered to be the Miass River. It is the main water artery of the Southern Urals. Its source is considered to be a key located in Bashkortostan on the Bolshoi Nurali ridge. It flows through the city of Miass, Argayashsky, Sosnovsky and Krasnoarmeisky districts, Chelyabinsk. Last modified: 2025-01-23 12:01

Not everyone knows what mosses are (the name of the species, genus). At best, from a school biology course, everyone remembers the familiar cuckoo flax or sphagnum. In reality, a fairly large group of these plants stands completely apart from other currently existing. Last modified: 2025-01-23 12:01

Pyramid is a polyhedron based on a polygon. The definition of "height of the pyramid" is very often found in geometry problems in the school curriculum. In the article we will try to consider different ways to find it. Last modified: 2025-01-23 12:01

Beijing is one of the largest cities in the world with a population of about 20 million people. The vast majority of the city's residents are ethnic Chinese. Only 11 million people living in the city are registered, the rest are visitors, tourists and illegal workers. Last modified: 2025-01-23 12:01