Waves surround us everywhere, as we live in a world of movements and sounds. What is the nature of the wave process, what is the essence of the theory of wave processes? Consider this as an example of experiments.
The concept of waves in physics
The common concept for many processes is the presence of sound. By the definition of sound, it is the result of rapid oscillatory movements that are created by air or another medium perceived by our auditory organs. Knowing this definition, we can proceed to consider the concept of “wave process”. There are a number of experiments that allow you to visually consider this phenomenon.
The studied wave processes in physics can be observed in the form of radio waves, sound, compression waves when using vocal cords. They spread through the air.
For a visual definition of a concept, a stone is thrown into a puddle and characterizes the spread of effects. This is an example of a gravitational wave. It arises as a result of raising and lowering the liquid.
Acoustics
A whole section called “Acoustics” is devoted to studying the properties of sound in physics. Let’s figure out what he characterizes. Let us focus on phenomena and processes in which everything is not clear, on problems that are still awaiting solution.
Acoustics, like other branches of physics, still has many unsolved mysteries. They have yet to open. Let us consider the wave process in acoustics.
Sound
This concept is associated with the presence of vibrational movements that are produced by particles of the medium. Sound is a series of oscillatory processes associated with the occurrence of waves. In the process of formation of compressions and discharges in the medium, a wave process arises.
The wavelength indices depend on the nature of the medium where the oscillatory processes take place. Almost all the phenomena that occur in nature are associated with the presence of sound vibrations and sound waves that propagate in the environment.
Examples of determining the wave process in nature
These movements can inform about the phenomenon of the wave process. High-frequency sound waves can travel thousands of kilometers, for example, if a volcanic eruption occurs.
During an earthquake, there are strong acoustic and geoacoustic vibrations that can be detected by special sound receivers.
During an underwater earthquake, an interesting and terrible phenomenon takes place - a tsunami, which is a huge wave that arose during a powerful underground or underwater manifestation of the elements.
Thanks to the acoustics, you can get information about what is approaching the tsunami. Many of these phenomena have long been known. But so far, some concepts of physics require careful study. Therefore, to study puzzles that have not yet been solved, it is sound waves that come to the rescue.
Theory of Tectonics
In the XVIII century, the "catastrophe hypothesis" was born. At that time, the concepts of "element" and "regularity" were not connected. Then they discovered that the age of the bottom of the oceans is much younger than land, and this surface is constantly updated.
It was at this time, thanks to a new view of the earth, that the crazy hypothesis grew into the theory of “Tectonics of lithospheric plates”, which claims that the earth’s mantle is moving, and the firmament is floating. Such a process is similar to the movement of perpetual ice drift.
To understand the described process, it is important to free oneself from stereotypes and habitual views, to realize other types of being.
Further advances in science
Geological life on earth has its time and state of matter. Science has managed to recreate the likeness. At the bottom of the ocean there is a continuous movement, in which breaks and rift ridges occur, when new substance rises to the surface from the depths of the earth and gradually cools.
At that time, processes occur on land when colossal plates of the lithosphere float on the surface of the earth's mantle - the upper stone shell of the earth that bears continents and the seabed.
The number of such plates totals about ten. The mantle is restless, therefore lithospheric plates begin to move. In the laboratory, this process has the appearance of an elegant experience.
In nature, this threatens with a geological catastrophe - an earthquake. The reason for the movement of lithospheric plates are global convection processes that occur in the depths of the earth. The result of drilling will be a tsunami.
Japan
Among other seismically dangerous areas of the earth, Japan occupies a special place, this chain of islands is called the "fire belt".
Closely monitoring the breathing of the earth’s firmament, one can predict an impending catastrophe. To study oscillatory processes, an ultra-deep drilling rig was introduced into the earth. It penetrated to a depth of 12 km and allowed scientists to draw conclusions about the presence of certain rocks inside the earth.
The speed of the electromagnetic wave is studied in physics lessons in grade 9. Show experience with weights located at an equal distance from each other. They are connected by the same springs of the usual form.
If you move the first weight to the right by a certain distance, the second remains in the same position for some time, but the spring is already beginning to compress.
The definition of wave
Since such a process occurred, an elastic force arose that would push the second weight. He will receive acceleration, after a while he will pick up speed, will shift in this direction and compress the spring between the second and third weights. In turn, the third one will get acceleration, start to accelerate, shift and affect the fourth spring. And so the process will occur on all elements of the system.
In this case, the shift of the second load in time will occur later than the first. The effect is always late in relation to the cause.
Also, the displacement of the second load will entail the displacement of the third. This process tends to spread to the right.
If the first load began to fluctuate in harmonic law, then this process will extend to the second weight, but with a delayed reaction. Therefore, if the first load is made to oscillate, it is possible to obtain an oscillation that will propagate in space over time. This is the definition of a wave.
Varieties of waves
Imagine a substance that consists of atoms, they:
- possess mass - as the weights proposed in the experiment;
- connect with each other, forming a solid by chemical bonds (as considered in the experiment with a spring).
It follows that the substance is a system resembling a model from experience. A mechanical wave may propagate in it . This process is associated with the emergence of elastic forces. Such waves are often called "elastic."
There are two types of elastic waves. To determine them, you can take a long spring, fix it on one side and stretch to the right. So you can see that the direction of wave propagation is along the spring. Particles of the medium are displaced in the same direction.
In such a wave, the character of the direction of particle oscillation coincides with the direction of wave propagation. This concept is called "longitudinal wave."
If you stretch the spring and give it time to come to rest, and then sharply change its position in the vertical direction, it will be seen that the wave propagates along the spring and is repeatedly reflected.
But the direction of particle oscillation is now vertical, and the wave propagation is horizontal. This is a shear wave. It can exist only in solids.
The speed of electromagnetic waves of different types is different. Seismologists successfully use this property to determine the distance to the earthquake foci.
When a wave propagates, particles oscillate along or across, but this is not accompanied by the transfer of matter, but only by movement. So indicated in the textbook "Physics" grade 9.
The characteristic of the wave equation
The wave equation in physical science is a kind of linear hyperbolic differential equation. It is also used for other areas covered by theoretical physics. This is one of the equations that mathematical physics uses for calculations. In particular, gravitational waves are described. Used to describe processes:
- in acoustics, as a rule, of a linear type;
- in electrodynamics.
Wave processes are displayed in the calculation for the multidimensional case of a homogeneous wave equation.
The difference between wave and wobble
Remarkable discoveries follow from reflection on an ordinary occurrence. Galileo took the beating of his heart for the standard of time. Thus, the constancy of the process of oscillations of the pendulum was discovered - one of the main provisions of mechanics. It is absolutely only for a mathematical pendulum - an ideal oscillatory system, which is characterized by:
- equilibrium position;
- by force returning the body to the equilibrium position when it is deflected;
- energy transitions when an oscillation occurs.
To bring the system out of balance, a condition for the appearance of oscillation is necessary. In this case, a certain energy is communicated. Different oscillatory systems require different types of energy.
Oscillation is a process that is characterized by a constant repetition of the movements or states of the system at certain periods of time. A vivid demonstration of the oscillatory process is an example of a swinging pendulum.
Oscillatory and wave processes are observed in almost all natural phenomena.
The wave has the function of disturbing or changing the state of the medium, propagated in space and carrying energy without the need to transfer matter. This is a distinctive property of wave processes; they have been studied in physics for a long time. In studies, the wavelength can be distinguished.
Sound waves can exist in all areas, they are not only in a vacuum. Special properties are possessed by electromagnetic waves. They can exist everywhere, even in a vacuum.
The energy of a wave depends on its amplitude. A circular wave, propagating from a source, scatters energy in space, so its amplitude decreases rapidly.
A linear wave has interesting properties. Its energy does not dissipate in space, so the amplitude of such waves decreases only due to the friction force.
The direction of wave propagation is represented by rays - lines that are perpendicular to the wave front.
The angle between the incident ray and the normal is the angle of incidence. Between the normal and the reflected beam is the angle of reflection. The equality of these angles is maintained at any position of the obstacle relative to the wave front.
When waves traveling in opposite directions meet, a standing wave can form.
Summary
Particles of the medium between adjacent nodes of a standing wave oscillate in the same phase. These are the parameters of the wave process recorded in the wave equations. When the waves meet, both increases and decreases in their amplitudes can be observed.
Knowing the main characteristics of the wave process, it is possible to determine the amplitude of the resulting wave at a given point. We will establish in what phase the wave from the first and second sources will arrive at this point. Moreover, the phases are opposite.
If the stroke difference is an odd number of half-waves, the amplitude of the resulting wave at this point will be minimal. If the path difference is zero or an integer of the wavelength, an increase in the amplitude of the resulting wave will be observed at the meeting point. This is an interference pattern when adding waves from two sources.
The frequency of electromagnetic waves is fixed in modern technology. The receiver must detect weak electromagnetic waves. If you put a reflector, more wave energy will get into the receiver. The reflector system is set so that it creates the maximum signal at the receiving device.
The characteristics of the wave process underlie modern ideas about the nature of light and the structure of matter. Thus, when studying them in the physics textbook of grade 9, you can successfully learn how to solve problems from the field of mechanics.