Physical phenomena that occur with physical bodies. Natural phenomena

About the world around us. In addition to ordinary curiosity, this was caused by practical needs. After all, for example, if you know how to lift
and move heavy stones, you will be able to build strong walls and build a house in which it is more convenient to live than in a cave or dugout. And if you learn to smelt metals from ores and make plows, scythes, axes, weapons, etc., you will be able to plow the field better and get a higher harvest, and in case of danger you will be able to protect your land.

In ancient times, there was only one science - it united all the knowledge about nature that humanity had accumulated by that time. Nowadays this science is called natural science.

Learning about physical science

Another example of an electromagnetic field is light. You will become familiar with some of the properties of light in Section 3.

3. Remembering physical phenomena

The matter around us is constantly changing. Some bodies move relative to each other, some of them collide and, possibly, collapse, others are formed from some bodies... The list of such changes can be continued and continued - it is not without reason that in ancient times the philosopher Heraclitus remarked: “Everything flows, everything changes.” Scientists call changes in the world around us, that is, in nature, a special term - phenomena.

Rice. 1.5. Examples of natural phenomena

Rice. 1.6. A complex natural phenomenon - a thunderstorm can be represented as a combination of a number of physical phenomena

Sunrise and sunset, gathering snow avalanche, a volcanic eruption, a horse running, a panther jumping - all these are examples of natural phenomena (Fig. 1.5).

To better understand complex natural phenomena, scientists divide them into a collection of physical phenomena - phenomena that can be described using physical laws.

In Fig. Figure 1.6 shows a set of physical phenomena that form a complex natural phenomenon - a thunderstorm. Thus, lightning - a huge electrical discharge - is an electromagnetic phenomenon. If lightning strikes a tree, it will flare up and begin to release heat - physicists in this case talk about a thermal phenomenon. The rumble of thunder and the crackle of flaming wood are sound phenomena.

Examples of some physical phenomena are given in the table. Take a look at the first row of the table, for example. What can be common between the flight of a rocket, the fall of a stone and the rotation of an entire planet? The answer is simple. All examples of phenomena given in this line are described by the same laws - the laws mechanical movement. Using these laws, we can calculate the coordinates of any moving body (be it a stone, a rocket or a planet) at any point in time that interests us.

Rice. 1.7 Examples of electromagnetic phenomena

Each of you, taking off a sweater or combing your hair with a plastic comb, probably paid attention to the tiny sparks that appeared. Both these sparks and the mighty discharge of lightning belong to the same electromagnetic phenomena and, accordingly, are subject to the same laws. Therefore, you should not wait for a thunderstorm to study electromagnetic phenomena. It is enough to study how safe sparks behave to understand what to expect from lightning and how to avoid possible danger. For the first time such research was carried out by the American scientist B. Franklin (1706-1790), who invented effective remedy lightning protection - lightning rod.

Having studied physical phenomena separately, scientists establish their relationship. Thus, a lightning discharge (an electromagnetic phenomenon) is necessarily accompanied by a significant increase in temperature in the lightning channel (a thermal phenomenon). The study of these phenomena in their interrelation made it possible not only to better understand the natural phenomenon of a thunderstorm, but also to find a way for the practical application of electromagnetic and thermal phenomena. Surely each of you, passing by a construction site, saw workers in protective masks and blinding flashes of electric welding. Electric welding (a method of joining metal parts using an electric discharge) is an example of the practical use of scientific research.

4. Determine what physics studies

Now that you have learned what matter and physical phenomena are, it is time to determine what the subject of physics is. This science studies: the structure and properties of matter; physical phenomena and their relationships.

• let's sum it up

The world around us consists of matter. There are two types of matter: the substance from which all physical bodies are made, and the field.

Changes are constantly taking place in the world that surrounds us. These changes are called phenomena. Thermal, light, mechanical, sound, electromagnetic phenomena are all examples of physical phenomena.

The subject of physics is the structure and properties of matter, physical phenomena and their relationships.

• Control questions

What does physics study? Give examples of physical phenomena. Can events that occur in a dream or imagination be considered physical phenomena? 4. What substances do the following bodies consist of: a textbook, a pencil, a soccer ball, a glass, a car? What physical bodies can consist of glass, metal, wood, plastic?

Physics. 7th grade: Textbook / F. Ya. Bozhinova, N. M. Kiryukhin, E. A. Kiryukhina. - X.: Publishing house "Ranok", 2007. - 192 p.: ill.

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Physical picture of the world

Physical phenomena in nature

Story

Many physical phenomena observed in nature and the life around us cannot be explained only on the basis of the laws of mechanics, molecular kinetic theory and thermodynamics. These phenomena manifest forces acting between bodies at a distance, and these forces do not depend on the masses of the interacting bodies and, therefore, are not gravitational. These forces are called electromagnetic forces.
The ancient Greeks knew about the existence of electromagnetic forces. But the systematic, quantitative study of physical phenomena in which the electromagnetic interaction of bodies is manifested began only at the end of the 18th century. Through the work of many scientists in the 19th century, the creation of a harmonious science studying electrical and magnetic phenomena was completed. This science, which is one of the most important branches of physics, is called electrodynamics.

Solar eclipse

This astronomical phenomenon, which is thatMoon covers (eclipses) completely or partiallySun from an observer on Earth. A solar eclipse is only possible innew moon , when the side of the Moon facing the Earth is not illuminated and the Moon itself is not visible. Eclipses are only possible if the new moon occurs near one of twolunar nodes (the point of intersection of the apparent orbits of the Moon and the Sun), no more than about 12 degrees from one of them.
Observers close to the total eclipse can see it as partial solar eclipse. During a partial eclipse, the Moon passes across the disk of the Sun not exactly in the center, hiding only part of it. At the same time, the sky darkens much less than during a total eclipse, and the stars do not appear. A partial eclipse can be observed at a distance of about two thousand kilometers from the total eclipse zone.
Total solar eclipses make it possible to observe the corona and the immediate vicinity of the Sun, which is extremely difficult under normal conditions (although with1996 Astronomers were able to constantly survey the surroundings of our star thanks to the workSOHO satellite (English Solar and Heliospheric Observatory - solar and heliospheric observatory)).
French scientist Pierre Jansen during a total solar eclipse in India August 18 1868 first explored chromosphere sun and received range new chemical element (however, as it turned out later, this spectrum could have been obtained without waiting solar eclipse, which is what the English astronomer did two months later Norman Lockyer ). This element was named after the Sun - helium .
IN 1882 , May 17 , during a solar eclipse by observers from Egypt A comet was spotted flying close to the Sun. It was called the Eclipse Comet, although it has another name - comet Tewfik (in honor of Khedive Egypt at that time). She was one of the circumsolar comets from Kreutz family .

Rainbow

This atmospheric optical And meteorological phenomenon usually observed in the field high humidity. It looks like a multi-coloredarc or circle , composed ofcolors spectrum (looking from outside - inside the arc:red , orange , yellow , green , blue , blue , violet . These seven colors are the main onesnames of colors , which are usually highlighted in the rainbow in Russian culture (perhaps following Newton,see below ), but it should be borne in mind that in fact the spectrum is continuous, and these colors in the rainbow transform into each other with a smooth change through many intermediateshades .
Rainbows occur because the sunlight experiences refraction V droplets water rain or fog, soaring in atmosphere. These droplets deflect light differently different colors (refractive index There is less water for longer wavelength (red) light than for shorter wavelength (violet), so red light bends less when refracted - red at 137°30’, violet at 139°20’, etc.), resulting inwhite light decomposes intorange . This phenomenon is causeddispersion . It seems to the observer that a multi-colored glow is emanating from space in concentric circles (arcs) (in this case, the source of bright light should always be behind the observer).
Rainbow representscaustics , which occurs whenrefraction And reflection (inside the drop) of a plane-parallel beam of light on a spherical drop. As shown in the picture (formonochrome beam), the reflected light has a maximum intensity for a certain angle between the source, the drop and the observer (and this maximum is very “sharp”, that is, most of the light refracted with reflection in the drop comes out almost exactly at the same angle). The fact is that the angle at which the reflected and refracted ray leaves the drop depends non-monotonically on the distance from the incident (initial) ray to the axis parallel to it and passing through the center of the drop (this dependence is quite simple, and it is not difficult to explicitly calculate ), and this dependence has a smoothextremum . Therefore, the “number of rays” emerging from the drop with angles close to the extreme angle value is “much greater” than the others. At this angle (which is slightly different for different indicators refraction for rays different color) and reflection-refraction of maximum brightness occurs, constituting (from different drops) a rainbow (“bright” rays from different drops form a cone with its apex in the observer’s pupil and an axis passing through the observer and the Sun) .

Geyser

A spring that periodically releases fountains hot water and a couple. Geysers are one of the manifestations of the later stagesvolcanism , common in areas of modern volcanic activity. Geysers can take the form of small truncated cones with fairly steep slopes, low, very flat domes, small bowl-shaped depressions, basins, irregular shape yam, etc.; in their bottom or walls there are exits of pipe-like or slot-like channels connected to the lava.
The activity of the geyser is characterized by periodic repetition of dormancy, filling the basin with water, gushing of a steam-water mixture and intense emissions of steam, gradually giving way to their quiet release, cessation of steam release and the onset of the resting stage.
There are regular and irregular geysers. For the former, the duration of the cycle as a whole and its individual stages is almost constant, for the latter it is variable, for different geysers the duration of individual stages is measured in minutes and tensminutes , the resting stage lasts from a few minutes to several hours or days.
There are about 30 geysers in Iceland, among which the Jumping Witch stands out (Gryla ), spewing a steam-water mixture to a height of 15 meters approximately every 2 hours. The island is also home to one of the most active geysers in the world -Strokkur
Large geysers in Kamchatka were discovered in1941 in the valley of the Geysernaya River (Valley of Geysers ), near volcano Kikhpinych. Total in Kamchatka before the mudflowJune 3 2007 there were about 100 geysers.

Tornado

An atmospheric vortex that occurs incumulonimbus (thunderstorm ) cloud and spreading down, often all the way to surface of the earth, in the form of a cloud sleeve or trunk with a diameter of tens and hundreds of meters
The reasons for the formation of tornadoes have not yet been fully studied. It is possible to indicate only a few general information, most characteristic of typical tornadoes.
Tornadoes go through three main stages in their development. At the initial stage, an initial funnel appears from a thundercloud, hanging above the ground. The cold layers of air located directly below the cloud rush down to be replaced by warm ones, which, in turn, rise upward. (suchunstable system usually formed by combining twoatmospheric fronts - warm and cold).Potential energy this system goes intokinetic energy rotational movement of air. The speed of this movement increases, and it takes on its classic appearance.

Eruption

It's a release process
etc.................

A phenomenon is any manifestation of something, as well as any change in the world around us. Meaning of this word determined by the context, namely the adjective next to the term “phenomenon”. It is difficult to understand what this phenomenon is without examples, so we will give them.

• A physical phenomenon can be considered a change state of aggregation substances.
• In this area there are such unusual natural phenomena like petrified waves.
• He was frightened by something that could be called paranormal activity.

Let us take a closer look at the term “Phenomenon” depending on the context.

What is a physical phenomenon

First of all, note that a physical phenomenon is a process, not a result of something. This is the process of ongoing changes in the state or position of physical systems. Remember that a physical phenomenon is one in which the transformation of one substance into another does not occur. Its composition will remain the same, but its condition or position will change.

Physical phenomena are classified as follows:

• Electrical phenomena. They participate electric charges. For example, lightning, electric current.
• Mechanical phenomena. The movement will be relative to each other. For example, the movement of cars on the road.
• Thermal phenomena. They are associated with changes in body temperature. For example, melting snow.
• Optical phenomena. They are associated with the metamorphoses of light rays. For example, a rainbow.
• Magnetic phenomena. Occurs when magnetic properties on this or that subject. For example, a compass with an arrow pointing north.
• Atomic phenomena. Occurs during metamorphosis during internal structure substances. For example, the glow of stars.

What are natural phenomena

Natural phenomena are considered to be climatic and meteorological manifestations of nature that occur naturally. Rain, snow, storm, earthquake are all examples of natural phenomena.

It is important to understand what a natural phenomenon is and how it is interconnected with physical phenomena. Thus, in one natural phenomenon one can count several physical phenomena. That is, the concept of “natural phenomenon” is broader. For example, a natural phenomenon such as a thunderstorm includes the following physical phenomena: the movement of clouds and rain (mechanical phenomena), lightning (electrical phenomenon), burning of a tree from a lightning strike (thermal phenomenon).

What is paranormal activity

When they talk about a paranormal phenomenon, they mean any changes in the surrounding reality that are not the norm, an ordinary phenomenon. They do not have scientific explanations, evidence. Their existence goes beyond the understanding of the usual picture of the world. Examples paranormal phenomena serve: crying icons, the biofield of living beings.

Dynamic change is built into nature itself. Everything changes one way or another every moment. If you look around carefully, you will find hundreds of examples of physical and chemical phenomena, which are quite natural transformations.

Change is the only constant in the Universe

Oddly enough, change is the only constant in our Universe. To understand physical and chemical phenomena (examples in nature are found at every step), it is customary to classify them into types, depending on the nature of the final result caused by them. There are physical, chemical and mixed changes, which contain both the first and the second.

Physical and chemical phenomena: examples and meaning

What is a physical phenomenon? Any change that occurs in a substance without changing it chemical composition, are physical. They are characterized by changes in physical attributes and material state (solid, liquid or gas), density, temperature, volume that occur without changing its fundamental chemical structure. New ones are not created chemical products or changes total mass. Additionally, this type of change is usually temporary and in some cases completely reversible.

When you mix chemicals in a laboratory, it's easy to see the reaction, but there's a lot going on in the world around you. chemical reactions every day. A chemical reaction changes molecules, while a physical change only rearranges them. For example, if we take chlorine gas and sodium metal and combine them, we get table salt. The resulting substance is very different from any of its components. This is a chemical reaction. If we then dissolve this salt in water, we are simply mixing salt molecules with water molecules. There is no change in these particles, it is a physical transformation.

Examples of physical changes

Everything is made of atoms. When atoms combine, different molecules are formed. The different properties that objects inherit are a consequence of different molecular or atomic structures. The basic properties of an object depend on their molecular arrangement. Physical changes occur without changing the molecular or atomic structure of objects. They simply transform the state of an object without changing its nature. Melting, condensation, volume change and evaporation are examples of physical phenomena.

Additional examples of physical changes: metal expanding when heated, sound transmitted through air, water freezing into ice in winter, copper being drawn into wires, clay forming on various objects, ice cream melting into a liquid, metal heating and changing into another form, iodine sublimation when heating, the fall of any object under the influence of gravity, ink being absorbed by chalk, magnetization of iron nails, a snowman melting in the sun, glowing incandescent lamps, magnetic levitation of an object.

How do you differentiate between physical and chemical changes?

Many examples of chemical and physical phenomena can be found in life. It is often difficult to tell the difference between the two, especially when both can occur at the same time. To determine physical changes, ask the following questions:

• Is the state of an object's state a change (gaseous, solid, and liquid)?
• Is the change purely limited physical parameter or a characteristic such as density, shape, temperature or volume?
• Is the chemical nature of the object a change?
• Do chemical reactions occur that lead to the creation of new products?

If the answer to one of the first two questions is yes, and the answers to subsequent questions are no, it is most likely a physical phenomenon. And vice versa, if the answer to any of the two latest questions positive, while the first two are negative, this is definitely a chemical phenomenon. The trick is to simply observe clearly and analyze what you see.

Examples of chemical reactions in everyday life

Chemistry happens in the world around you, not just in the laboratory. Matter interacts to form new products through a process called a chemical reaction or chemical change. Every time you cook or clean, it's chemistry in action. Your body lives and grows through chemical reactions. There are reactions when you take medication, light a match and sigh. Here are 10 chemical reactions in Everyday life. This is just a small sampling of the physical and chemical phenomena in life that you see and experience many times every day:

1. Photosynthesis. Chlorophyll in plant leaves converts carbon dioxide and water into glucose and oxygen. It is one of the most common daily chemical reactions, and also one of the most important because it is how plants make food for themselves and animals and convert carbon dioxide into oxygen.
2. Aerobic cellular respiration is a reaction with oxygen in human cells. Aerobic cellular respiration is the opposite process of photosynthesis. The difference is that energy molecules combine with the oxygen we breathe to release the energy our cells need, as well as carbon dioxide and water. The energy used by cells is chemical energy in the form of ATP.
3. Anaerobic respiration. Anaerobic respiration produces wine and other fermented foods. Your muscle cells perform anaerobic respiration when you deplete the oxygen supply, such as during intense or prolonged exercise. Anaerobic respiration by yeasts and bacteria is used for fermentation to produce ethanol, carbon dioxide and other chemicals that produce cheese, wine, beer, yogurt, bread and many other common foods.
4. Combustion is a type of chemical reaction. This is a chemical reaction in everyday life. Every time you light a match or a candle, or start a fire, you see a combustion reaction. Combustion combines energy molecules with oxygen to produce carbon dioxide and water.
5. Rust is a common chemical reaction. Over time, iron develops a red, flaky coating called rust. This is an example of an oxidation reaction. Other everyday examples include the formation of verdigris on copper and tarnishing of silver.
6. Mixing chemicals causes chemical reactions. Baking powder and baking soda perform similar functions in baking, but they react differently to other ingredients, so you can't always substitute another. If you combine vinegar and baking soda for a chemical "volcano" or milk and baking powder in a recipe, you are experiencing a double displacement or metathesis reaction (plus a few others). The ingredients are recombined to produce carbon dioxide gas and water. Carbon dioxide forms bubbles and helps "grow" bakery products. These reactions appear simple in practice, but often involve several steps.
7. Batteries are examples of electrochemistry. Batteries use electrochemical or redox reactions to convert chemical energy into electrical energy.
8. Digestion. Thousands of chemical reactions occur during digestion. As soon as you put food in your mouth, an enzyme in your saliva called amylase begins to break down sugars and other carbohydrates into more simple shapes, which your body can absorb. The hydrochloric acid in your stomach reacts with food to break it down, and enzymes break down proteins and fats so they can be absorbed into the blood through the intestinal wall.
9. Acid-base reactions. Whenever you mix an acid (such as vinegar, lemon juice, sulfuric acid, hydrochloric acid) with alkali (for example, baking soda, soap, ammonia, acetone), you perform an acid-base reaction. These processes neutralize each other, producing salt and water. Sodium chloride is not the only salt that can be formed. For example, here is chemical equation for an acid-base reaction that produces potassium chloride, a common table salt substitute is: HCl + KOH → KCl + H 2 O.
10. Soap and detergents. They are purified through chemical reactions. Soap emulsifies dirt, which means oil stains bind to the soap so they can be removed with water. Detergents reduce the surface tension of water so they can interact with oils, sequestering them and washing them away.
11. Chemical reactions during cooking. Cooking is one big practical chemistry experiment. Cooking uses heat to cause chemical changes in food. For example, when you boil an egg hard, hydrogen sulfide produced by heating the egg white can react with the iron from the egg yolk, forming a gray-green ring around the yolk. When you cook meat or baked goods, the Maillard reaction between amino acids and sugars produces Brown color and desired taste.

Other examples of chemical and physical phenomena

Physical properties describe characteristics that do not change the substance. For example, you can change the color of the paper, but it's still paper. You can boil water, but when you collect and condense the steam, it is still water. You can determine the mass of a piece of paper, and it is still paper.

Chemical properties are those that show how a substance reacts or does not react with other substances. When sodium metal is placed in water, it reacts violently to form sodium hydroxide and hydrogen. Enough heat is generated as the hydrogen escapes into the flame, reacting with the oxygen in the air. On the other hand, when you put a piece of copper metal in water, no reaction occurs. Thus, chemical property The chemical property of sodium is that it reacts with water, but the chemical property of copper is that it does not.

What other examples of chemical and physical phenomena can be given? Chemical reactions always occur between electrons in the valence shells of atoms of elements in periodic table. Physical phenomena at low energy levels simply involve mechanical interactions—random collisions of atoms without chemical reactions, such as atoms or gas molecules. When collision energies are very high, the integrity of the nucleus of atoms is disrupted, leading to fission or fusion of the species involved. Spontaneous radioactive decay usually considered a physical phenomenon.

Science arose as a result of man's study of nature

Which combined all the knowledge existing at that time. This science was called differently, for example, natural philosophy. Then, due to expansion and deepening scientific knowledge separate sciences emerged that study certain groups of phenomena.

Physics studies general patterns natural phenomena, properties and structure of matter, laws of its motion.

Translated from Greek, the word “physics” means “nature”. This name was used by Aristotle in the 4th century. BC e.

Do you think physics is currently the only natural science?

If not, then try to name other sciences.

Children will almost certainly name botany, zoology, geology, geography, astronomy, chemistry and something more sophisticated (microbiology, genetics, acoustics or entomology). Attempts to include history or ethnography in this list are not excluded - this will give rise to a discussion of the specific features of the natural sciences. For each of the named sciences, the object of study is specified, and, if possible, the literal translation of the name of the science.

You see what a long list of sciences we have received, and this is only a small part of them! All these sciences (they are called natural) study natural phenomena. They are closely related to physics and rely on its achievements.

2. Natural phenomena are everything that naturally occurs in nature.

Natural phenomena are everything that happens in nature.

To explain a phenomenon means to indicate its causes: the change of day and night is explained by the rotation of the Earth around its axis; to explain the change of seasons, we had to thoroughly understand the movement of the Earth in its orbit around the Sun; The occurrence of wind is associated with different heating of the air in different places...

The natural phenomena studied by physics are called physical phenomena. All these phenomena can be divided into groups:

1) mechanical (falling stones, rolling balls, movement of the Earth around the Sun);

2) thermal (water boiling, ice melting, cloud formation)

3) electrical (lightning, heating of a conductor by current);

4) magnetic (attraction of iron objects to a magnet, interaction of magnets);

5) light (glow from a lamp or flame, obtaining images using a lens or mirror).

Physical phenomena:

1) mechanical;

2) thermal;

3) electrical;

4) magnetic;

5) light.

Of course, demonstrations are needed here (it is possible to use video clips): for example, rolling a ball and a cart down an inclined plane, Franklin’s boiler, “hovering” ceramic magnets, the glow of a light bulb from a set of universal transformers. You can invite students to observe their own images in convex or concave mirrors, to obtain an inverted image of trees outside the window on the screen using a converging lens, etc. Of great interest are video recordings of solar and lunar eclipses. Physics has long explained all the phenomena that you have just observed. Over time, as you study physics, you will understand why a cart overtakes a ball, why magnets “float” in the air, what the operating principle of electrical appliances is, and much, much more. However, there are still many phenomena that are mysterious to physicists. No one has yet explained the nature of ball lightning, we do not fully understand the “behavior” elementary particles... And what could be more interesting than riddles that no one has yet solved? Each science has its own language. We need to get acquainted with the "ABC" physical language, i.e. with basic concepts and terms. We already know what a physical phenomenon is. Let's name a few more dates.

Any object is called a physical body.

Matter is what physical bodies are made of. Matter is everything that exists in the Universe. Look around and name the physical bodies that surround us. Now name the substances that make up these bodies.

Children give many examples; You can draw their attention to the fact that air is also a “full-fledged” substance.

What other physical bodies and substances can you name?

Can you name any type of matter that is not substance?

With some help, children name light (no physical body can be made of light!) and sometimes radio waves. Light and radio waves are examples of fields.