Examples of physical phenomena and their description. Examples of chemical and physical phenomena in nature What are physical phenomena examples

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, a 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 of mechanical motion. 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 an effective means of protection against lightning discharges - a 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.

• Security 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.

Various changes constantly occur in nature (living and nonliving). The sun rises and sets - night changes to day. During a thunderstorm, lightning flashes and thunder rumbles over and over again. Trees are covered with green foliage in spring. An airplane flies high in the sky. By pressing the button on the remote control, we turn on the TV.

All changes that occur in nature are called natural phenomena.

In every science, words or phrases are used that are the names of certain concepts - terms. You have already used the mathematical terms “graph”, “figure”, “formula”, you know what words such as “subject”, “sentence”, “suffix”, “poem”, etc. mean in Ukrainian language and literature. In physics There are also deadlines. One of the most general concepts used in physics is the concept of matter. In physics, matter is understood as everything that exists in nature, regardless of whether we know about its existence or not.

Changes occurring in nature are a manifestation of the movement of matter. An airplane flies in the sky, a drop of rain falls, a boat floats past the shore, a student goes to school. In all these cases, we see that over time the positions of the aircraft relative to the cloud and the raindrop on the window glass change, and the student approaches the school.

The phenomena that we perceive as the movement of various objects and their parts relative to each other are called mechanical phenomena.

The movement of matter can be invisible to us: puddles dry up after rain, water boils in a kettle, steel melts in an open-hearth furnace, the sun's rays heat the earth. Such phenomena are called thermal. Thermal phenomena are associated with changes in the microcosm - the invisible movement of atoms, molecules, and their radiation.

When darkness falls, we turn on the lights. The action of electrical devices is a consequence of the movement and interaction of electrical charges, the carriers of which are elementary particles - even smaller formations than molecules and atoms. In this case we are dealing with electrical phenomena. Lightning is one of the manifestations of electrical phenomena occurring in nature (Fig. 1.1).

Magnetic phenomena are closely related to electrical phenomena. The magnetic compass needle changes orientation if you place a wire nearby and pass an electric current through it. Magnetic phenomena are becoming of great importance for the operation of electric motors, widely used in everyday life, industry and transport. One of the manifestations of electrical and magnetic phenomena in nature are auroras (Fig. 1.2).

A rainbow after the rain (Fig. 1.3), the blueness of the sky, the image on the screen in a cinema, the play of colors on the wings of a butterfly and the surface of a compact disc are manifestations of light phenomena (Fig. 1.4).

All these phenomena are studied by physics, which is why they are called physical phenomena.

Phenomena occurring in nature are interconnected, because these are manifestations of the movement of matter. Current flowing through the coil of a light bulb (electrical phenomenon) causes it to glow (thermal phenomenon) and emit light (optical phenomenon). Due to a lightning discharge, the air heats up and expands rapidly, which is why we hear thunder. By studying various phenomena, physicists find out the reason for their origin and the connection between them.

In physics, the term physical body or simply body is widely used. For example, if the general features of mechanical motion are studied, then it does not matter which body will move. A stone, ball, apple or any other object that is thrown upward or at an angle to the horizon will increase its movement, and, having reached the highest position, will begin to fall with increasing speed. When studying such movements, physicists say: a body is thrown vertically upward or a body is thrown at an angle to the horizon. The movements of the spacecraft that deliver astronauts to the International Space Orbital Station and the ships that bring them new cargo are subject to the same laws.

Heating an aluminum or steel frying pan is the same in nature. Therefore, the term body in physics means any object when studying mechanical, thermal or other phenomena that occur with their participation. Examples physical bodies there is a stone, a lark, a ship, water in a pot, gas in a cylinder, a car, a balloon and air in it, the Earth.

QUESTIONS AND TASKS

1. What is meant by a physical phenomenon?

2. What is matter?

3. What types of physical phenomena do you know?

4. Give two or three examples of mechanical, thermal, electrical, optical phenomena that you observed during the day.

5. Give examples of physical bodies that you used in physics class, at home during lunch, that you saw while going to school.

Since ancient times, people have been collecting information about the world in which they live. There was only one science that united all the information about nature that humanity had accumulated at that time. At that time, people did not yet know that they were observing examples of physical phenomena. Currently, this science is called “natural science”.

What does physical science study?

Over time, scientific ideas about the world around us have changed noticeably - there are many more of them. Natural science split into many separate sciences, including: biology, chemistry, astronomy, geography and others. In a number of these sciences, physics occupies not the last place. Discoveries and achievements in this field have allowed humanity to acquire new knowledge. These include the structure and behavior of various objects of all sizes (from giant stars to the smallest particles - atoms and molecules).

The physical body is...

There is a special term “matter”, which in scientific circles is used to describe everything that is around us. A physical body consisting of matter is any substance that occupies a certain place in space. Any physical body in action can be called an example of a physical phenomenon. Based on this definition, we can say that any object is a physical body. Examples of physical bodies: button, notepad, chandelier, cornice, Moon, boy, clouds.

What is a physical phenomenon

Any matter is in constant change. Some bodies move, others come into contact with others, and others rotate. It is not for nothing that many years ago the philosopher Heraclitus uttered the phrase “Everything flows, everything changes.” Scientists even have a special term for such changes - these are all phenomena.

Physical phenomena include everything that moves.

What types of physical phenomena are there?

• Thermal.

These are phenomena when, due to the effects of temperature, some bodies begin to transform (shape, size and condition change). An example of physical phenomena: under the influence of the warm spring sun, icicles melt and turn into liquid; with the onset of cold weather, puddles freeze, boiling water becomes steam.

• Mechanical.

These phenomena characterize a change in the position of one body in relation to the others. Examples: a clock is running, a ball is jumping, a tree is shaking, a pen is writing, water is flowing. They are all in motion.

• Electrical.

The nature of these phenomena fully justifies their name. The word “electricity” has its roots in Greek, where “electron” means “amber.” The example is quite simple and probably familiar to many. When you suddenly take off your woolen sweater, you hear a small crack. If you do this by turning off the light in the room, you can see sparkles.

• Light.

A body participating in a phenomenon associated with light is called luminous. As an example of physical phenomena, we can cite the well-known star of our solar system - the Sun, as well as any other star, a lamp, and even a firefly bug.

• Sound.

The propagation of sound, the behavior of sound waves when colliding with an obstacle, as well as other phenomena that are somehow related to sound, belong to this type of physical phenomena.

• Optical.

They happen thanks to light. For example, humans and animals are able to see because there is light. This group also includes the phenomena of propagation and refraction of light, its reflection from objects and passage through different media.

Now you know what physical phenomena are. However, it is worth understanding that there is a certain difference between natural and physical phenomena. Yes, when natural phenomenon Several physical phenomena occur simultaneously. For example, when lightning strikes the ground, the following effects occur: sound, electrical, thermal and light.

Physical bodies are " actors» physical phenomena. Let's get to know some of them.

Mechanical phenomena

Mechanical phenomena are the movement of bodies (Fig. 1.3) and their action on each other, for example repulsion or attraction. The action of bodies on each other is called interaction.

We will get to know mechanical phenomena in more detail this academic year.

Rice. 1.3. Examples of mechanical phenomena: movement and interaction of bodies during sports competitions(a, b. c); movement of the Earth around the Sun and its rotation around its own axis (g)

Sound phenomena

Sound phenomena, as the name suggests, are phenomena involving sound. These include, for example, the propagation of sound in air or water, as well as the reflection of sound from various obstacles - say, mountains or buildings. When sound is reflected, a familiar echo appears.

Thermal phenomena

Thermal phenomena are the heating and cooling of bodies, as well as, for example, evaporation (the transformation of a liquid into steam) and melting (the transformation of a solid into a liquid).

Thermal phenomena are extremely widespread: for example, they determine the water cycle in nature (Fig. 1.4).

Rice. 1.4. Water cycle in nature

The water of the oceans and seas, heated by the sun's rays, evaporates. As the steam rises, it cools, turning into water droplets or ice crystals. They form clouds from which water returns to Earth in the form of rain or snow.

The real “laboratory” of thermal phenomena is the kitchen: whether soup is being cooked on the stove, whether water is boiling in a kettle, whether food is frozen in the refrigerator - all these are examples of thermal phenomena.

The operation of a car engine is also determined by thermal phenomena: when gasoline burns, a very hot gas is formed, which pushes the piston (motor part). And the movement of the piston is transmitted through special mechanisms to the wheels of the car.

Electrical and magnetic phenomena

The most striking (in the literal sense of the word) example of an electrical phenomenon is lightning (Fig. 1.5, a). Electric lighting and electric transport (Fig. 1.5, b) became possible thanks to the use of electrical phenomena. Examples of magnetic phenomena are the attraction of iron and steel objects by permanent magnets, as well as the interaction of permanent magnets.

Rice. 1.5. Electrical and magnetic phenomena and their uses

The compass needle (Fig. 1.5, c) rotates so that its “north” end points north precisely because the needle is a small permanent magnet, and the Earth is a huge magnet. The Northern Lights (Fig. 1.5, d) are caused by the fact that electrically charged particles flying from space interact with the Earth as with a magnet. Electrical and magnetic phenomena determine the operation of televisions and computers (Fig. 1.5, e, f).

Optical phenomena

Wherever we look, we will see optical phenomena everywhere (Fig. 1.6). These are phenomena associated with light.

An example of an optical phenomenon is the reflection of light by various objects. Rays of light reflected by objects enter our eyes, thanks to which we see these objects.

Rice. 1.6. Examples of optical phenomena: The sun emits light (a); The moon reflects sunlight (b); Mirrors (c) reflect light especially well; one of the most beautiful optical phenomena - rainbow (d)