It is not easy to find an adult who has never heard the catchphrase “Movement is life” in his life.
There is another formulation of this statement, which sounds slightly different: “Life is movement.” The authorship of this aphorism is usually attributed to Aristotle, an ancient Greek scientist and thinker who is considered the founder of all “Western” philosophy and science.
Today it is difficult to say with complete certainty whether the great ancient Greek philosopher ever actually uttered such a phrase, and how exactly it sounded in those distant times, but, looking at things with an open mind, we must admit that the above definition of movement, although sonorous, is rather vague and metaphorical. Let's try to figure out what movement is from a scientific point of view.
The concept of motion in physics
Physics gives the concept "movement" a very specific and unambiguous definition. The branch of physics that studies the movement of material bodies and the interaction between them is called mechanics.
The branch of mechanics that studies and describes the properties of motion without taking into account its specific causes is called kinematics. From the point of view of mechanics and kinematics, motion is considered to be a change in the position of a physical body relative to other physical bodies that occurs over time.
What is Brownian motion?
The tasks of physics include observing and studying any manifestations of movement that occur or could occur in nature.
One type of motion is the so-called Brownian motion, known to most readers of this article from a school physics course. For those who, for some reason, were not present when studying this topic or have completely forgotten it, let us explain: Brownian motion is the random movement of the smallest particles of matter. 
Brownian motion occurs wherever there is any matter whose temperature exceeds absolute zero. Absolute zero is the temperature at which the Brownian motion of particles of a substance should cease. On the Celsius scale, which we are used to using in everyday life to determine the temperature of air and water, the temperature of absolute zero is 273.15 °C with a minus sign.
Scientists have not yet been able to create conditions that cause such a state of matter; moreover, there is an opinion that absolute zero is a purely theoretical assumption, but in practice it is unattainable, since it is impossible to completely stop the vibrations of particles of matter.
Movement from a biological point of view
Since biology is closely related to physics and, in a broad sense, is completely inseparable from it, in this article we will also look at movement from the point of view of biology. In biology, movement is considered as one of the manifestations of the vital activity of an organism. From this point of view, movement is the result of the interaction of forces external to an individual organism with the internal forces of the organism itself. In other words, external stimuli cause a certain reaction of the body, which manifests itself in movement.
It should be noted that although the formulations of the concept of “motion” adopted in physics and biology are somewhat different from each other, in essence they do not enter into the slightest contradiction, being simply different definitions of the same scientific concept. 
Thus, we are convinced that the catchphrase discussed at the beginning of this article is completely consistent with the definition of movement from the point of view of physics, so we can only once again repeat the common truth: movement is life, and life is movement .
In physics, there is such a thing as mechanical motion, the definition of which is interpreted as a change in the coordinates of a body in three-dimensional space relative to other bodies with the loss of time. Oddly enough, you can, for example, exceed the speed of a bus without moving anywhere. This value is relative and dependent on a given point. The main thing is to fix the frame of reference in order to observe the point in relation to the object.
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Description
Physics concepts:
- A material point is a part of a body or an object with small parameters and mass that are not taken into account when studying the process. This is a quantity that is neglected in physics.
- Displacement is the distance traveled by a material point from one coordinate to another. The concept should not be confused with motion, since in physics it is the definition of a path.
- The distance traveled is the distance that an object has traversed. What is the distance traveled is considered by the section of physics under called "Kinematics".
- A trajectory in space is a straight or broken line along which an object travels. You can imagine what a trajectory is, according to the definition from the field of physics, by mentally drawing a line.
- Mechanical is movement along a given path.
Attention! The interaction of bodies is carried out according to the laws of mechanics, and this section is called kinematics.
Understand what a coordinate system is and what a trajectory is in practice?
It is enough to mentally find a point in space and draw coordinate axes from it, the object will move relative to it along a broken or straight line, and the types of movement will also be different, including translational, carried out when oscillating and rotating.
For example, a cat is in a room, moves to any object or changes its location in space, moving along different trajectories.
The distance between objects may vary because the selected paths are not the same.
Types
Known types of movement:
- Progressive. Characterized by the parallelism of two interconnected points moving equally in space. An object moves forward when it passes along one line. It is enough to imagine replacing the refill in a ballpoint pen, that is, the refill moves forward along a given path, with each part moving parallel and equally. This happens quite often in mechanisms.
- Rotational. An object describes a circle in all planes that are parallel to each other. The axes of rotation are the centers of the described ones, and the points located on the axis are motionless. The rotating axis itself can be located inside the body (rotational), and also connected to its external points (orbital). To understand what it is, you can take a regular needle and thread. Hold the latter between your fingers and gradually unwind the needle. The needle will describe a circle, and such types of movement should be classified as orbital. An example of a rotational view: spinning an object on a hard surface.
- Oscillatory. All points of a body moving along a given trajectory are repeated accurately or approximately at the same time. A good example is a puck suspended on a cord, oscillating left and right.
Attention! Features of forward movement. An object moves in a straight line, and at any time interval all its points move in the same direction - this is forward motion. If a bicycle is riding, then at any time you can separately consider the trajectory of its any point, it will be the same. It doesn’t matter whether the surface is flat or not.
These types of movements occur every day in practice, so it won’t be difficult to play them out mentally.
What is relativity
According to the laws of mechanics, an object moves relative to some point.
For example, if a person stands still and a bus moves, this is called the relativity of the movement of the vehicle in question to the object.
The speed at which an object moves relative to a certain body in space is also taken into account relative to this body and, accordingly, acceleration also has a relative characteristic.
Relativity is a direct dependence of the trajectory specified during the movement of the body, the path traveled, speed characteristics, as well as displacement in relation to reference systems.
How is the countdown carried out?
What is a reference system and how is it characterized? The reference in relation to the spatial coordinate system, the primary reference to the time of movement - this is the reference system. In different systems, one body may have different locations.
The point is located in the coordinate system; when it begins to move, its movement time is taken into account.
Reference body - it is an abstract object located at a given point in space. When orienting to its position, the coordinates of other bodies are considered. For example, a car stands still and a person moves; in this case, the reference body is a car.
Uniform movement
The concept of uniform motion - this definition in physics is interpreted as follows.
Mechanical movement is a change in the position of a body in space relative to other bodies.
For example, a car is moving along the road. There are people in the car. People move along with the car along the road. That is, people move in space relative to the road. But relative to the car itself, people do not move. This shows up. Next we will briefly consider main types of mechanical movement.
Forward movement- this is the movement of a body in which all its points move equally.
For example, the same car makes forward motion along the road. More precisely, only the body of the car performs translational motion, while its wheels perform rotational motion.
Rotational movement is the movement of a body around a certain axis. With such a movement, all points of the body move in circles, the center of which is this axis.
The wheels we mentioned perform rotational motion around their axes, and at the same time, the wheels perform translational motion along with the car body. That is, the wheel makes a rotational movement relative to the axis, and a translational movement relative to the road.
Oscillatory motion- This is a periodic movement that occurs alternately in two opposite directions.
For example, a pendulum in a clock performs an oscillatory motion.
Translational and rotational movements are the simplest types of mechanical movement.
Relativity of mechanical motion
All bodies in the Universe move, so there are no bodies that are at absolute rest. For the same reason, it is possible to determine whether a body is moving or not only relative to some other body.
For example, a car is moving along the road. The road is located on planet Earth. The road is still. Therefore, it is possible to measure the speed of a car relative to a stationary road. But the road is stationary relative to the Earth. However, the Earth itself revolves around the Sun. Consequently, the road along with the car also revolves around the Sun. Consequently, the car makes not only translational motion, but also rotational motion (relative to the Sun). But relative to the Earth, the car makes only translational motion. This shows relativity of mechanical motion.
Relativity of mechanical motion– this is the dependence of the trajectory of the body, the distance traveled, movement and speed on the choice reference systems.
Material point
In many cases, the size of a body can be neglected, since the dimensions of this body are small compared to the distance that this body moves, or compared to the distance between this body and other bodies. To simplify calculations, such a body can conventionally be considered a material point that has the mass of this body.
Material point is a body whose dimensions can be neglected under given conditions.
The car we have mentioned many times can be taken as a material point relative to the Earth. But if a person moves inside this car, then it is no longer possible to neglect the size of the car.
As a rule, when solving problems in physics, we consider the movement of a body as motion of a material point, and operate with such concepts as the speed of a material point, the acceleration of a material point, the momentum of a material point, the inertia of a material point, etc.
Frame of reference
A material point moves relative to other bodies. The body in relation to which this mechanical movement is considered is called the body of reference. Reference body are chosen arbitrarily depending on the tasks to be solved.
Associated with the reference body coordinate system, which is the reference point (origin). The coordinate system has 1, 2 or 3 axes depending on the driving conditions. The position of a point on a line (1 axis), plane (2 axes) or in space (3 axes) is determined by one, two or three coordinates, respectively. To determine the position of the body in space at any moment in time, it is also necessary to set the beginning of the time count.
Frame of reference is a coordinate system, a reference body with which the coordinate system is associated, and a device for measuring time. The movement of the body is considered relative to the reference system. The same body relative to different reference bodies in different coordinate systems can have completely different coordinates.
Trajectory of movement also depends on the choice of reference system.
Types of reference systems can be different, for example, a fixed reference system, a moving reference system, an inertial reference system, a non-inertial reference system.
Movement is any change in general, from the spatial movement of objects to human thinking. Movement is an attribute of matter, an integral property of any material object. There is no matter without movement and vice versa. Movement is an abstraction, the ability to change its parameters, abstracted by our consciousness from real material objects. Therefore, movement in its “pure form” exists only in thinking, but in reality only moving material objects exist. There cannot be an absolutely motionless material object. Rest is the opposite of movement (lack of movement). Any moving object is determined. time retains its qualitative certainty, the stability of the internal structure, that is, some constancy, immutability. This is an indispensable condition for the existence of any thing. That. -movement and rest are dialectically contradictory properties of a material object. Development is an irreversible qualitative change. It can be progressive - occurring with an increase in the complexity and orderliness of the object, and regressive - degradation of the object, its disintegration, death. Engels identified 5 main forms of movement:
- 1. Mechanical
- 2. Physical
- 3. Chemical
- 4. Biological
- 5. Social
All these forms of movement are interconnected and simpler ones are included in more complex ones, forming a qualitatively different form of movement. Each of these forms includes an infinite number of types of movement. Even, according to Engels, the simplest mechanical motion includes such types of motion as uniformly rectilinear, uniformly accelerated (slow), curvilinear, chaotic, etc.
The most complex form of movement is social, since the material carrier is the most complex type of matter - social. This form of movement also includes changes that occur in the individual’s body. Thus, the human heart is a mechanical engine that ensures the movement of blood in the vessels. But this is not a purely mechanical engine. Its activity is regulated by the mechanisms of human higher nervous activity. And the vital activity of the body is a condition for human participation in work and in public life. This includes changes in social groups, strata, classes, ethnic changes, demographic processes, the development of productive forces and production relations and other changes determined by the laws of motion at the social level of matter.
It should be emphasized that various forms of motion are capable of transforming into each other in accordance with the laws of conservation of matter and motion. This is a manifestation of the property of indestructibility and non-creation of matter and motion. The measure of motion of matter is energy, the measure of rest and inertia is mass.
Matter is an objective reality given to us in sensations. Matter is one of the most general categories of our thinking. It contains only a minimal number of signs of the designated object. The first step in concretizing I-I matter is the recognition of the complex organization of objective reality, within which material objects (things), as well as their properties and relationships, are distinguishable. The next step in concretizing the concept of matter is the attribution of certain general attributive properties to all material objects. Properties: consistency (orderliness, structural certainty), activity (movement, change, development), self-organization, spatio-temporal form of existence, reflection, information content. Structural levels of organization of matter: First, we define three large types of systems based on complexity: systems of inanimate nature, biosystems and social systems. Next, within each of these types of systems, we look for structural levels in inanimate nature - physical vacuum, particles, fields, atoms, molecules. In living nature - nucleic acids, proteins, cells, biocenoses. In the organization of social life, systems and subsystems of human action are visible (material and spiritual production, politics, morality). Thus, the material world is a multi-tiered structure formed by the structural levels of matter.
The principle of determinism. Categories of cause and effect, necessity and chance, possibility and reality
Determinism is the doctrine of the objective natural relationship and interdependence of things, processes and phenomena of the real world. Determinism presupposes the presence of various objectively existing forms of interconnection between phenomena, many of which are expressed in the form of relationships that are not directly causal in nature, i.e. not directly containing moments of generation, production of one by another. This includes spatial and temporal correlations, functional dependencies, symmetry relationships, interactions of parts in systems of interdetermination of parts and the whole, connection of states in movement and development, etc.
Cause and investigation. When one phenomenon, under certain conditions, modifies or gives rise to another phenomenon, the first acts as a cause, the second as a consequence. Causality is a connection that always brings into being something new, turning possibility into reality. The principle of causality is of great importance in the scientific knowledge of reality. The interaction of cause and effect is called the feedback principle, which operates in all self-organizing systems where perception, storage, processing and use of information occur. The reasons are external and internal. The internal cause operates within the framework of a given system, and the external cause characterizes the interaction of one cause with another. Objective reasons are realized beyond the will and consciousness of people. Subjective reasons lie in the purposeful actions of people, in their determination, organization, experience, and knowledge. The immediate causes are those cat. directly cause and determine this action. Indirect - which cause and determine a given action through a number of intermediate links.
Necessity and chance. Accident is something that, under given conditions, may or may not happen; it may happen one way, but it may also happen another way. Randomness can be external and internal. An example of an external accident is that a man stepped on a watermelon rind and fell. What is internal randomness? According to Darwin's theory, imperceptible random changes beneficial to them are fixed by heredity. Both necessary and random events occur in the surrounding world. Necessity is a development of phenomena that inevitably follows from the internal, essential properties and relationships of these phenomena. Necessity can be internal and external, i.e. generated by the object’s own nature or a combination of external circumstances. It can be characteristic of many objects or a single object. Chance is in diverse connections with necessity, due to which necessity manifests itself in the form of chance, and the border between chance and necessity is never closed. However, the main direction of development is determined precisely by necessity.
Possibility and reality. Reality is understood as the creative result of the action of all the real forces of the world: this is nature and world history, man and his mind, material and spiritual culture, this is the unity of essence and phenomenon, internal and external, necessary and accidental, individual and general. D. is something that has already arisen, has come true, that lives and acts. Possibility is the future in the present, it is something that does not exist in a given qualitative certainty, but that can arise and exist, become reality under certain conditions. In time, possibility precedes reality. But reality, being the result of previous development, is at the same time the starting point of further development. Possibility arises in a given reality and is realized in a new reality.
Quantities describing motion
The branch of physics that studies the behavior of moving objects is called kinematics. In kinematics, the movements of a material point are often considered. Knowing what movement is, you should list the main elements that are directly related to it:
- A trajectory is an imaginary line in space along which a body moves. It can be rectilinear, parabolic, elliptical and so on.
- Path (S) is the distance that a material point travels during its movement. Path in SI system is measured in meters (m).
- Velocity (v) is a physical quantity that determines how far a material point travels per unit time. It is measured in meters per second (m/s).
- Acceleration (a) is a quantity that describes the change in the speed of movement of a material point. In SI it is expressed in m/s 2.
- Travel time (t).
Laws of motion. Their mathematical formulation
Having understood what movement is and what quantities determine it, we can write an expression for the path: S = v*t. The motion described by this equation is called uniform rectilinear motion. If the speed of the material point changes, then the formula for the path should be written as follows: S = v 0 *t+a*t 2 /2, here the speed v 0 is called the initial one (at time t=0). At any other moment of time t, the speed of a material point is determined by the formula: v = v 0 + a*t. This type of motion is called rectilinear uniformly accelerated (uniformly decelerated).
The considered formulas are quite simple, since they are used for rectilinear motion. In nature, objects often move along curved trajectories. In these cases, it is important to take into account the vector properties of velocity and acceleration. For example, one of the simple movements along a curved path is the movement of a material point along a circle. In this case, the concept of centripetal acceleration is introduced, which determines the change not in the magnitude of the velocity, but in its direction. This acceleration is calculated by the formula: a = v 2 /R, where R is the radius of the circle.
Movement examples
Having understood the question of what movement is, it is useful to give some examples in everyday life and nature for clarity.
Moving a car along the roadway, riding a bicycle, bouncing a ball on the lawn, sailing a ship in the sea, flying an airplane in the sky, a skier descending a snowy mountain slope, a sprinter running at a sports competition - all these are examples of the movement of objects in everyday life.
The rotation of planets around the Sun, the fall of a stone to the ground, the vibration of leaves and branches of trees under the influence of the wind, the movement of cells that make up the tissues of living organisms, and finally, the thermal chaotic movement of atoms and molecules - these are examples of the movement of natural objects.
If we approach the issue from a philosophical point of view, we should say that movement is a fundamental property of existence, since everything that exists around us is in constant motion and change.