Bodies are objects that surround us.

Bodies are made up of substances.

Physical bodies differ in shape, size, have mass, volume.

Matter is what the physical body is made of. The essential property of a substance is its mass.

Material is the substance from which bodies are made.

Define "substance", "material", "body".

What is the difference between "substance" and "body"? Give examples. Why are there more bodies than substances?

Figures and facts

One ton of waste paper can produce 750 kg of paper or 25,000 school notebooks.

20 tons of waste paper save a hectare of forest from cutting down.

inquisitive

In the aviation and space industries, in gas turbines, in plants for the chemical processing of coal, where the temperature is high, composite materials are used. These are materials consisting of a plastic base (matrix) and a filler. Composites include ceramic-metal materials (cermets), norplasts (filled organic polymers). As a matrix, metals and alloys, polymers, and ceramics are used. Composites are much more durable than traditional materials.

home experiment

Chromatography on paper

Mix a drop of blue and red ink (maybe a mixture of water-soluble paints that do not interact with each other). Take a sheet of filter paper, apply a small drop of the mixture to the center of the paper, then water drips into the center of this drop. A color chromatogram will begin to form on the filter paper.

Familiarization with laboratory glassware and chemical equipment

In the process of studying chemistry, many experiments have to be carried out, for which special equipment and utensils are used.

In chemistry, special dishes made of thin-walled and thick-walled glass are used. Products made of thin-walled glass are resistant to temperature extremes; chemical operations that require heating are carried out in them. Thick glassware should not be heated. By appointment, glassware can be general purpose, special purpose and measured. General purpose cookware is used for most jobs.

Thin-walled General Purpose Glassware

Test tubes are used when performing experiments with small amounts of solutions or solids, for demonstration experiments. Let's use the utensils to perform the experiments.

Pour into two small test tubes of 1-2 ml. hydrochloric acid solution. In one add 1-2 drops of litmus, and the second - so much methyl orange. We observe the change in the color of the indicators. Litmus turns red and methyl orange turns pink.

Pour into three small test tubes 1-2 ml of sodium hydroxide solution. Add 1-2 drops of litmus to one, the color becomes blue. In the second - the same amount of methyl orange - the color becomes yellow. In the third - phenolphthalein, the color becomes crimson. So, with the help of indicators, you can determine the environment of solutions.

Place a little soda sodium hydrogen carbonate in a large test tube and add 1-2 ml of acetic acid solution. We immediately observe a kind of “boiling” of a mixture of these substances. This impression is created due to the rapid release of carbon dioxide bubbles. If a lit match is brought into the upper particle of the test tube when gas is released, it goes out without burning out.

Substances are dissolved in flasks, solutions are filtered and titrated. Chemical beakers are used to carry out precipitation reactions, the dissolution of solids when heated. The group of special purpose includes dishes used for a specific purpose. In thick-walled dishes, experiments are performed that do not require heating. Most often, reagents are stored in it. Droppers, funnels, gasometers, Kipp apparatus, glass rods are also made from thick glass.

We dip one glass rod in concentrated r hydrochloric acid, and the second in r ammonia. Let's bring the sticks closer to each other, we observe the formation of "smoke without fire".

In measuring utensils belong pipettes, burettes, flasks, cylinders, beakers, glasses. Measuring utensils accurately determine the volume of liquids, prepare solutions of various concentrations.

In addition to glassware, porcelain dishes are used in the laboratory: cups, crucibles, mortars. Porcelain cups are used to evaporate solutions, and porcelain crucibles are used to calcinate substances in muffle furnaces. Mortars grind solids.

Laboratory equipment

To heat substances in chemical laboratories, alcohol stoves, electric stoves with a closed spiral, water baths, and, in the presence of gas, gas burners are used. You can also use dry fuel, burning it on special stands.

Auxiliaries are of great importance when performing chemical experiments: a metal stand, a stand for test tubes, crucible tongs, asbestos mesh.

Scales are used to weigh substances.

In today's article, we will discuss what the physical body is. this term has already met you more than once during the years of schooling. We first encounter the concepts of "physical body", "substance", "phenomenon" in the lessons of natural history. They are the subject of study of most sections of the special science - physics.

According to "physical body" means a certain material object that has a form and a clearly defined outer boundary that separates it from the external environment and other bodies. In addition, the physical body has such characteristics as mass and volume. These parameters are basic. But there are others besides them. We are talking about transparency, density, elasticity, hardness, etc.

Physical bodies: examples

To put it simply, we can call any of the surrounding objects a physical body. The most familiar examples of them are a book, a table, a car, a ball, a cup. The physicist calls a simple body that whose geometric shape is simple. Composite physical bodies are those that exist in the form of combinations of simple bodies fastened together. For example, a very conditionally human figure can be represented as a set of cylinders and balls.

The material of which any of the bodies consists is called substance. At the same time, they can contain in their composition both one and a number of substances. Let's give examples. Physical bodies - cutlery (forks, spoons). They are usually made from steel. A knife can serve as an example of a body composed of two different kinds of substances - a steel blade and a wooden handle. And such a complex product as a cell phone is made from a much larger number of "ingredients".

What are the substances

They can be natural or artificially created. In ancient times, people made all the necessary items from natural materials (arrowheads - from clothes - from animal skins). With the development of technological progress, substances created by man appeared. And now they are in the majority. A classic example of a physical body of artificial origin is plastic. Each of its types was created by a person in order to ensure the necessary qualities of a particular object. For example, transparent plastic - for glasses lenses, non-toxic food - for dishes, durable - for car bumpers.

Any object (from to a high-tech device) has a number of certain qualities. One of the properties of physical bodies is their ability to attract each other as a result of gravitational interaction. It is measured using a physical quantity called mass. By definition of physicists, the mass of bodies is a measure of their gravity. It is denoted by the symbol m.

Mass measurement

This physical quantity, like any other, can be measured. To find out what is the mass of any object, you need to compare it with the standard. That is, with a body whose mass is taken as a unit. The international system of units (SI) is the kilogram. Such an "ideal" unit of mass exists in the form of a cylinder, which is an alloy of iridium and platinum. This international design is kept in France, and copies are available in almost every country.

In addition to kilograms, the concept of tons, grams or milligrams is used. Body weight is measured by weighing. This is a classic way for everyday calculations. But in modern physics there are others that are much more modern and highly accurate. With their help, the mass of microparticles, as well as giant objects, is determined.

Other properties of physical bodies

Shape, mass and volume are the most important characteristics. But there are other properties of physical bodies, each of which is important in a particular situation. For example, objects of equal volume can differ significantly in their mass, that is, have different densities. In many situations, characteristics such as brittleness, hardness, resilience or magnetic qualities are important. We should not forget about thermal conductivity, transparency, homogeneity, electrical conductivity and other numerous physical properties of bodies and substances.

In most cases, all such characteristics depend on the substances or materials of which the objects are composed. For example, rubber, glass and steel balls will have completely different sets of physical properties. This is important in situations where bodies interact with each other, for example, in studying the degree of their deformation when colliding.

About accepted approximations

Certain sections of physics consider the physical body as a kind of abstraction with ideal characteristics. For example, in mechanics, bodies are represented as material points that do not have mass and other properties. This branch of physics deals with the movement of such conditional points, and for solving the problems posed here, such quantities are of no fundamental importance.

In scientific calculations, the concept of an absolutely rigid body is often used. Such is conditionally considered a body that is not subject to any deformations, with no displacement of the center of mass. This simplified model makes it possible to theoretically reproduce a number of specific processes.

The section of thermodynamics for its own purposes uses the concept of a completely black body. What is it? A physical body (a certain abstract object) capable of absorbing any radiation falling on its surface. At the same time, if the task so requires, they can emit electromagnetic waves. If, according to the conditions of theoretical calculations, the shape of physical bodies is not fundamental, it is considered by default that it is spherical.

Why are the properties of bodies so important?

Physics itself, as such, originated from the need to comprehend the laws by which physical bodies behave, as well as the mechanisms for the existence of various external phenomena. Natural factors include any changes in our environment that are not related to the results of human activity. Many of them are used by people to their advantage, but others can be dangerous and even catastrophic.

The study of the behavior and various properties of physical bodies is necessary for people in order to predict adverse factors and prevent or reduce the harm they cause. For example, by building breakwaters, people are accustomed to dealing with the negative manifestations of the sea. Mankind has learned to resist earthquakes by developing special earthquake-resistant building structures. The load-bearing parts of the car are made in a special, carefully calibrated form to reduce damage in accidents.

About the structure of bodies

According to another definition, the term "physical body" means everything that can be recognized as really existing. Any of them necessarily occupies a part of space, and the substances of which they are composed are a collection of molecules of a certain structure. Its other, smaller particles are atoms, but each of them is not something indivisible and completely simple. The structure of an atom is rather complicated. In its composition, one can distinguish positively and negatively charged elementary particles - ions.

The structure, according to which such particles line up in a certain system, for solids is called crystalline. Any crystal has a certain, strictly fixed shape, which indicates the ordered movement and interaction of its molecules and atoms. When the structure of crystals changes, a violation of the physical properties of the body occurs. The state of aggregation, which can be solid, liquid or gaseous, depends on the degree of mobility of elementary components.

To characterize these complex phenomena, the concept of compression coefficients or volumetric elasticity, which are mutually reciprocal, is used.

Molecule movement

The state of rest is not inherent in either atoms or molecules of solids. They are in constant motion, the nature of which depends on the thermal state of the body, and the influences to which it is currently exposed. Part of the elementary particles - negatively charged ions (called electrons) moves at a higher speed than those with a positive charge.

From the point of view of the state of aggregation, physical bodies are solid objects, liquids or gases, which depends on the nature of molecular motion. The whole set of solids can be divided into crystalline and amorphous. The motion of particles in a crystal is recognized as completely ordered. In liquids, molecules move according to a completely different principle. They move from one group to another, which can be figuratively represented like comets wandering from one celestial system to another.

In any of the gaseous bodies, the molecules have a much weaker bond than in liquid or solid. Particles there can be called repulsive from each other. The elasticity of physical bodies is determined by a combination of two main quantities - the shear coefficient and the coefficient of volume elasticity.

Body fluidity

Despite all the significant differences between solid and liquid physical bodies, their properties have much in common. Some of them, called soft ones, occupy an intermediate state of aggregation between the first and second ones with physical properties inherent in both. Such a quality as fluidity can be found in a solid body (an example is ice or shoe pitch). It is also inherent in metals, including rather hard ones. Under pressure, most of them are able to flow like a liquid. By joining and heating two solid pieces of metal, it is possible to solder them into a single whole. Moreover, the soldering process takes place at a temperature much lower than the melting point of each of them.

This process is possible provided that both parts are in full contact. It is in this way that various metal alloys are obtained. The corresponding property is called diffusion.

About liquids and gases

Based on the results of numerous experiments, scientists have come to the following conclusion: solid physical bodies are not some isolated group. The difference between them and liquid ones is only in greater internal friction. The transition of substances to different states occurs under conditions of a certain temperature.

Gases differ from liquids and solids in that there is no increase in the elastic force even with a strong change in volume. The difference between liquids and solids is in the occurrence of elastic forces in solids during shear, that is, a change in shape. This phenomenon is not observed in liquids, which can take any of the forms.

Crystalline and amorphous

As already mentioned, two possible states of solids are amorphous and crystalline. Amorphous bodies are bodies that have the same physical properties in all directions. This quality is called isotropy. Examples include hardened resin, amber products, glass. Their isotropy is the result of the random arrangement of molecules and atoms in the composition of matter.

In the crystalline state, elementary particles are arranged in a strict order and exist in the form of an internal structure, periodically repeating in different directions. The physical properties of such bodies are different, but in parallel directions they coincide. This property inherent in crystals is called anisotropy. Its reason is the unequal force of interaction between molecules and atoms in different directions.

Mono- and polycrystals

In single crystals, the internal structure is homogeneous and repeats throughout the volume. Polycrystals look like a lot of small crystallites chaotically intergrown with each other. Their constituent particles are located at a strictly defined distance from each other and in the right order. A crystal lattice is understood as a set of nodes, that is, points that serve as centers of molecules or atoms. Metals with a crystalline structure serve as a material for the frames of bridges, buildings and other durable structures. That is why the properties of crystalline bodies are carefully studied for practical purposes.

Real strength characteristics are negatively affected by crystal lattice defects, both surface and internal. A separate section of physics, called solid body mechanics, is devoted to similar properties of solids.

"How the world works" - Inanimate nature RAIN CLAY CLOUD GOLD. How the world works. What is nature? The sky is light blue. The sun shines golden, The wind plays with leaves, A cloud floats in the sky. Live nature. Types of nature. Living and non-living nature are connected with each other. Living nature is studied by science - biology. Can man do without nature?

"Colorful rainbow" - The sun shines and laughs, And the rain pours down on the Earth. The work of the primary school teacher Kucherova I.V. And the seven-colored arc goes out into the meadows. Know Sitting. Where. Colors of rainbow. Pheasant. Why is the rainbow multicolored? Hunter. Desires. The sun's rays, falling into the sky on raindrops, break up into multi-colored rays.

"Inhabitants of the soil" - And people said: "Land to live!". The boots said, "Land to walk on." Medvedka. The soil. Toad. Earthworm. A bucket of potatoes in a wonderful pantry turns into twenty buckets. Soil dwellers. A. Teterin. Ground beetle. Scolopendra. The shovel said, "Earth to dig." Ticks. May beetle larva.

"Protection of nature" - We ourselves are a part of Nature, And small fish ... I want to be transported here ... We all live on the same planet. And our green forest. And a man without nature?... LET'S PRESERVE NATURE Completed by: Ilya Kochetygov, 5 "B". Nature can exist without man, Man! Let's protect and preserve our nature! Insects also need protection

"The composition of the soil" - Contents. There is water in the soil. Sand settles to the bottom, and clay on top of the sand. The soil. Water. Experience number 2. There is humus in the soil. Experience number 3. The soil contains salts. Experience number 1. There is air in the soil. Experience number 5. Soil composition. Humus. Fertility is the main property of the soil. Experience number 4. Sand. Air.

"A game about nature" - The Cape. Bullfrog. Raspberry. The sound of what amphibian is heard at 2-3 km? Cherry. Primary school teacher MAOU secondary school No. 24 Rodina Victoria Evgenievna. Chamomile. Hedgehog. Turtle. Celandine. Porcupine. A game. Medicinal plants. Clover. Lily of the valley. Cicada. But since childhood I have respected the Heart remedy. Leafy sea dragon.

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In life, we are surrounded by various bodies and objects. For example, indoors it is a window, a door, a table, a light bulb, a cup, on the street - a car, a traffic light, asphalt. Any body or object is made up of matter. This article will discuss what a substance is.

What is chemistry?

Water is an essential solvent and stabilizer. It has strong heat capacity and thermal conductivity. The aquatic environment is favorable for the occurrence of basic chemical reactions. It is transparent and practically resistant to compression.

What is the difference between inorganic and organic substances?

There are no particularly strong external differences between these two groups of substances. The main difference lies in the structure, where inorganic substances have a non-molecular structure, and organic substances have a molecular structure.

Inorganic substances have a non-molecular structure, therefore, they are characterized by high melting and boiling points. They do not contain carbon. These include noble gases (neon, argon), metals (calcium, calcium, sodium), amphoteric substances (iron, aluminum) and non-metals (silicon), hydroxides, binary compounds, salts.

Organic substances of molecular structure. They have fairly low melting points and decompose rapidly when heated. Mostly composed of carbon. Exceptions: carbides, carbonates, oxides of carbon and cyanides. Carbon allows the formation of a huge number of complex compounds (more than 10 million are known in nature).

Most of their classes belong to biological origin (carbohydrates, proteins, lipids, nucleic acids). These compounds include nitrogen, hydrogen, oxygen, phosphorus and sulfur.

To understand what a substance is, it is necessary to imagine what role it plays in our life. Interacting with other substances, it forms new ones. Without them, the vital activity of the surrounding world is inseparable and unthinkable. All objects are made up of certain substances, so they play an important role in our lives.