Pentenes are hydrocarbons with the molecular formula C5H10, saturated acyclic hydrocarbons of the alkane class. They have five carbon atoms in the molecule (from other Greek πέντε - five). Isopentane has a narcotic effect. Hazard class four. Last modified: 2025-06-01 07:06
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Copper acetylenide is a derivative of acetylene in which hydrogen atoms are replaced by copper atoms. According to its properties, this compound is a s alt of a very weak acid - acetylene. Copper(I) acetylide, like most metal derivatives of acetylene, is explosive. Last modified: 2025-01-23 12:01
It is well known that all forms of living matter, from viruses to highly organized animals (including humans), have a unique hereditary apparatus. It is represented by molecules of two types of nucleic acids: deoxyribonucleic and ribonucleic. In these organic substances, information is encoded, which is transmitted from parent individuals to offspring during reproduction. Last modified: 2025-06-01 07:06
RNA is an essential component of the molecular genetic mechanisms of the cell. The content of ribonucleic acids is a few percent of its dry weight, and about 3-5% of this amount falls on messenger RNA (mRNA), which is directly involved in protein synthesis, contributing to the implementation of the genome. Last modified: 2025-01-23 12:01
Scientists believe that the last dinosaur died 65 million years ago. We were taught this at school, all respected and serious scientific publications repeat this. But is it really so? Why is the number of researchers growing every year who unanimously claim that dinosaurs died out much later, and our ancestors still saw huge reptiles alive and unharmed?. Last modified: 2025-01-23 12:01
With the growth in the size of large cities and the number of large industries, we are increasingly confronted with such concepts as sound and noise. Many do not suspect the impact these phenomena have on human he alth. But the damaging factors of sound cannot be ignored. Knowing how to deal with invisible danger is important these days. Last modified: 2025-06-01 07:06
Mythological thinking is the most ancient type of thinking. With its help, a person began to learn events, objects and phenomena. Thanks to the rich imagination and childish naivety of ancient people, in the piggy bank of world mythology, you can find many interesting stories and legends and find out how much our view of the world differs from the worldview of our ancestors. Last modified: 2025-01-23 12:01
Plant cloning is such a natural process that almost everyone involved in agriculture and gardening has done it. There are differences between conventional cloning and microcloning. Their stages are in many ways similar, but each method has its pros and cons, which we will list in this article. Last modified: 2025-01-23 12:01
Gradually, many new things are entering our lives. The development of technology does not stand still, and tomorrow it may be possible what yesterday we did not dare to dream of. The neurocomputer interface (NCI) makes real the connection between the human brain and technology, their partial interaction. Last modified: 2025-01-23 12:01
The concept of "genesis" is used in cases where you need to say about the origin, the origin of something. The word "genesis" in Russian came from the Greek genesis - occurrence, formation and is used as a component of compound words denoting the causes of the birth of a phenomenon. Last modified: 2025-01-23 12:01
Harold Garfinkel, sociologist, born October 29, 1917. He was Distinguished Professor of Sociology at UCLA from 1954 until his retirement in 1987. In the 1950s he coined the term ethnomethodology. Last modified: 2025-01-23 12:01
Complete, adequate representation of knowledge, which is perceived equally unambiguously by both people and machines, is the main problem of modern information exchange. Such information exchange is based on a system of concepts and relationships that make up knowledge. Last modified: 2025-01-23 12:01
In everyday life, a person constantly encounters manifestations of oscillatory motion. This is the swing of the pendulum in the clock, the vibrations of automobile springs and the entire car. Even an earthquake is nothing but vibrations of the earth's crust. High-rise buildings also sway from strong gusts of wind. Let's try to figure out how physics explains this phenomenon. Last modified: 2025-01-23 12:01
Organosilicon compounds: general description, classification, examples of substances. General chemical properties. Characterization of high molecular weight organosilicon compounds. Receiving and analysis. Application in various branches of human activity. Production in Russia. Last modified: 2025-01-23 12:01
Root pressure is a vital parameter for all plants that exist in nature. This is due to the fact that they lack the circulation of juice, in the manner of the movement of blood in the veins of animal organisms. The pressure in the roots causes the sap to move in the "body" of the plant. In this article, we will look at what root pressure means, what is its role in plant life. Last modified: 2025-01-23 12:01
Is there water in the soil? Of course yes! It comes from atmospheric precipitation, the amount of which depends on meteorological conditions and the climate of a particular area. The water regime of soils is the most important characteristic that determines the conditions for the productivity and growth of tree plantations. Last modified: 2025-01-23 12:01
At the end of the 19th century, a theory was formulated, the authors of which were not familiar with each other, but at the same time came to the same conclusion. They were William James and Carl Lange. Their theory described emotions and corresponding manifestations in a person. What are scientists talking about? How can the knowledge described in this theory be applied?. Last modified: 2025-01-23 12:01
Nickel silver is a metallic alloy consisting predominantly of copper with additions of nickel and zinc. In some way, it is an analogue of an older alloy of the same composition - cupronickel, but cheaper than it. Nickel silver is used to make parts of measuring instruments, medical instruments, jewelry, cutlery and much more. Last modified: 2025-01-23 12:01
Mechanical devices are often used in human activities. The reliability of moving parts in any mechanism is ensured by reducing friction and deformation. For this, special materials called antifriction are used. Their main purpose is to reduce the coefficient of friction, facilitating the sliding of the moving surfaces of mechanisms. This article will consider the anti-friction properties of various materials used for these purposes. Last modified: 2025-01-23 12:01
Daniel Bell (born May 10, 1919, New York, New York, USA - died January 25, 2011, Cambridge, Massachusetts) was an American sociologist and journalist who used sociological theory to reconcile what , in his opinion, were the inherent contradictions of capitalist societies. He introduced the concept of a mixed economy, combining private and public elements. Last modified: 2025-06-01 07:06
The human body is a very complex system that is engaged in the implementation of a variety of processes. One of them is mineral metabolism. It is worth noting that this process is a combination of several separate smaller procedures occurring inside the body. Last modified: 2025-01-23 12:01
It must be admitted: a significant part of the population is not interested in pseudoscience and the fight against it. However, pseudoscience is currently one of the most serious problems facing the scientific community. Its occurrence, signs and examples, as well as methods of dealing with it are described in this article. Last modified: 2025-01-23 12:01
Despite the long tradition of studying the universe, man does not know much about it. Most of the information was obtained within a relatively small region of space called the Local Group of Galaxies. This article talks about what this area is. Last modified: 2025-01-23 12:01
Since the 19th century, conservative ideology has been an element of political life and a factor in social development. How the principles of conservatism arose, what evolution they went through, as well as their application in law is described in this article. Last modified: 2025-01-23 12:01
Crisis is an unpleasant inevitability. Any system, one way or another, faces serious problems, the fight against which is a test of strength. What types of crises exist are described in this article. Last modified: 2025-01-23 12:01
At the turn of the 19th-20th centuries, a new branch of scientific knowledge arises - the psychology of management, and one of the most popular is the theory of scientific organization of labor developed by Frederick Taylor. Taylor outlined his main ideas in the book "Principles of Scientific Management", published in 1911. Last modified: 2025-01-23 12:01
The article will discuss what an explosive device is, what it is for, how it appeared, varieties and applications. Last modified: 2025-01-23 12:01
Today, more than 7 billion people live on our planet. Scientists predict that by 2050 this figure could increase to 9 billion. We are all alike - and each of us is unique. People differ in appearance, skin color, culture and character. Today we will talk about the most obvious difference in our population - skin color. Last modified: 2025-01-23 12:01
The article describes a s alt such as manganese (II) sulfate. Here, its methods of obtaining, chemical and physical properties are analyzed. The use of this substance in agriculture as a fertilizer is disclosed in detail. Last modified: 2025-01-23 12:01
Scientists believe that people have observed alien ships since ancient times. This is confirmed by numerous myths, legends and stories that describe amazing objects flying across the sky, as well as creatures that came out of them. Last modified: 2025-01-23 12:01
Habitable Earth-like planets - is it a fantasy? The researchers suggest that those in the universe are not uncommon. Last modified: 2025-01-23 12:01
Crick Francis Harry Compton was one of two molecular biologists who unraveled the mystery of the structure of the genetic information carrier deoxyribonucleic acid (DNA), thereby laying the foundation for modern molecular biology. Last modified: 2025-01-23 12:01
At present, the historical path traversed by mankind is divided into the following segments: the primitive era, the history of the Ancient World, the Middle Ages, New, Modern times. It should be noted that today among scientists who study the stages of human development, there is no consensus on periodization. Last modified: 2025-01-23 12:01
UFO over Omsk appears regularly, according to eyewitnesses, strange flying objects are frequent visitors to the skies. It is foolish to deny the existence of another, more developed universal mind. Someone is leading us, because someone is always leading someone. But isn't it naive to believe that this reason wants to be noticed by us? Or does it not matter to them?. Last modified: 2025-01-23 12:01
Scientists have always been the most important people in history. Who should know every person who considers himself educated?. Last modified: 2025-01-23 12:01
The first people, their appearance and development is the mystery, the interest in which will never fade away. The appearance of a wide variety of versions - from divine origin to the arrival of aliens - poses a problem for scientists to search for new human remains and attract methods and means from various fields of knowledge to explain them. Last modified: 2025-01-23 12:01
Any object, being tossed up, sooner or later ends up on the earth's surface, be it a stone, a piece of paper or a simple feather. At the same time, a satellite launched into space half a century ago, a space station or the Moon continue to rotate in their orbits, as if they were not affected by the force of gravity of our planet at all. Why is this happening? Why does the Moon not threaten to fall to the Earth, and the Earth does not move towards the Sun? Isn't gravity acting on them?. Last modified: 2025-01-23 12:01
The question of what time is, has long worried mankind. Partly for this reason, Einstein's theory of relativity, which talks about relativistic time dilation, has become one of the most resonant and discussed in the history of physics. Last modified: 2025-01-23 12:01
Alpha Centauri is the closest star to us. Fantasists inhabit her life, scientists seek to find them near the planet. Most of the data on the star was obtained by indirect observation methods. It will become possible to reveal all its secrets only after a flight to Alpha Centauri, which, according to scientists, will not be possible earlier than in 200 years. Last modified: 2025-01-23 12:01
The question of the structure of the Universe and the place of the planet Earth and human civilization in it has been of interest to scientists and philosophers since time immemorial. For a long time, the so-called Ptolemaic system, later called geocentric, was in use. According to her, in the center of the world was the Earth, around which other planets made their way, as well as the Sun, stars and other celestial bodies. Last modified: 2025-01-23 12:01