Waves surround us everywhere, as we live in a world of movement and sound. What is the nature of the wave process, what is the essence of the theory of wave processes? Let's look at this with an example of experiments.
The concept of waves in physics
A common concept for many processes is the presence of sound. By definition, sound is the result of rapid oscillatory movements that are created by air or other 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 waves, compression waves when using the vocal cords. They spread through the air.
To visually define the concept, throw a stone into a puddle and characterize the spread of effects. This is an example of a gravitational wave. It occurs due to the rise and fall of the liquid.
Acoustics
A whole section called "Acoustics" is devoted to the study of the properties of sound in physics. Let's see what it characterizes. Let's focus on things andprocesses in which everything is not yet clear, on problems that are still waiting to be solved.
Acoustics, like other branches of physics, still has many unsolved mysteries. They are yet to be opened. Let's consider the wave process in acoustics.
Sound
This concept is associated with the presence of oscillatory movements, which are produced by the particles of the medium. Sound is a series of oscillatory processes associated with the appearance of waves. In the process of formation in the medium of compression and rarefaction, a wave process occurs.
The wavelength indicators depend on the nature of the medium where oscillatory processes take place. Almost all 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, such as when a volcano erupts.
When an earthquake occurs, strong acoustic and geoacoustic vibrations occur, which can be registered 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 acoustics, you can get information that a tsunami is approaching. Many of these phenomena have been known for a long time. But until now, some concepts of physicsrequire careful study. Therefore, for the study of mysteries that have not yet been solved, it is sound waves that come to the rescue.
Theory of tectonics
In the 18th 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 ocean floor is much younger than the land, and this surface is constantly being updated.
It was at this time, thanks to a new look at the earth, that crazy hypothesis grew into the theory of "Tectonics of the lithospheric plates", which states that the earth's mantle moves, and the firmament floats. Such a process is similar to the movement of eternal ice.
To understand the described process, it is important to get rid of stereotypes and habitual views, to realize other types of being.
Further advances in science
Geological life on earth has its own time and state of matter. Science has succeeded in recreating the likeness. The bottom of the ocean is constantly moving, causing ruptures and ridge formations as new matter rises from the depths of the earth to the surface and gradually cools.
At this 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, which carries the continents and the seabed.
The number of such plates is about ten. The mantle is restless, so the lithospheric plates begin to move. Under laboratory conditions, this process has the appearance of a graceful experience.
In nature, it threatens a geological disaster- earthquake. The reason for the movement of lithospheric plates is the global convection processes that occur in the depths of the earth. The result of the seething 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 following the breath of the earth's firmament, one can predict the impending catastrophe. To study oscillatory processes, an ultra-deep drilling rig was introduced into the thickness of 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 an electromagnetic wave is studied at physics lessons in grade 9. Show experience with weights located at an equal distance from each other. They are connected by identical springs of the usual form.
If you shift the first weight to the right a certain distance, the second one remains in the same position for a while, but the spring is already starting to compress.
Definition of the term "wave"
Since such a process has taken place, an elastic force has arisen that will push the second weight. He will get acceleration, after a while he will pick up speed, move in this direction and compress the spring between the second and third weights. In turn, the third will receive acceleration, start to accelerate, shift and affect the fourth spring. And so the process will take place on all elements of the system.
In this case, the displacement of the second load alongtime will occur later than the first. The effect always lags behind 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 weight began to fluctuate according to the harmonic law, then this process will spread to the second weight, but with a delayed reaction. Therefore, if you make the first weight vibrate, you can get an oscillation that will spread in space over time. This is the definition of a wave.
Varieties of waves
Let's imagine a substance that consists of atoms, they are:
- have mass - like the weights proposed in the experiment;
- connect to each other, forming a solid body through chemical bonds (as discussed in the experiment with a spring).
It follows that matter is a system resembling a model from experience. It can propagate a mechanical wave. This process is associated with the emergence of elastic forces. Such waves are often referred to as "bouncy".
There are two types of elastic waves. To determine them, you can take a long spring, fix it on one side and stretch it to the right. So you can see that the direction of wave propagation is along the spring. The particles of the medium move in the same direction.
In such a wave, the nature 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 cometo a state of rest, and then abruptly change the position in the vertical direction, it will be seen that the wave propagates along the spring and is reflected many times.
But the particle oscillation direction is now vertical, and the wave propagation is horizontal. This is a transverse wave. It can only exist in solids.
The speed of electromagnetic wave of different kind is different. This property is successfully used by seismologists to determine the distance to earthquake sources.
When a wave propagates, particles oscillate along or across, but this is not accompanied by the transfer of matter, but only by movement. So it is indicated in the textbook "Physics" Grade 9.
Characterization 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, linear type;
- in electrodynamics.
Wave processes are displayed in the calculation for the multidimensional case of a homogeneous wave equation.
The difference between a wave and a swing
Remarkable discoveries come from thinking about an ordinary phenomenon. Galileo took the beating of his heart as the standard of time. Thus, the constancy of the process of pendulum oscillations was discovered - one of the main provisions of mechanics. Itabsolutely only for a mathematical pendulum - an ideal oscillatory system, which is characterized by:
- balance position;
- force that returns the body to its equilibrium position when it deviates;
- transitions of energy when fluctuation occurs.
To bring the system out of balance, the condition for the occurrence of oscillations is necessary. In this case, a certain energy is reported. Different vibratory systems require different types of energy.
Oscillation is a process that is characterized by a constant repetition of movements or states of the system in certain periods of time. A clear demonstration of the oscillatory process is the example of a swinging pendulum.
Oscillatory and wave processes are observed in almost all natural phenomena. Wave has the function of perturbing or changing the state of the medium, propagating 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. When researching, you can highlight the wavelength.
Sound waves can exist in all spheres, they do not exist only in a vacuum. Electromagnetic waves have special properties. They can exist everywhere, even in a vacuum.
The energy of a wave depends on its amplitude. The circular wave, propagating from the source, scatters energy in space, so its amplitude rapidly decreases.
A linear wave has interesting properties. Its energy is not dissipated in space, thereforethe amplitude of such waves decreases only due to the force of friction.
The direction of wave propagation is depicted 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 preserved at any position of the obstacle relative to the wave front.
When waves moving in opposite directions meet, a standing wave can form.
Results
Particles of the medium between adjacent nodes of a standing wave oscillate in the same phase. These are the parameters of the wave process fixed in the wave equations. When 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. Let us determine in what phase the wave from the first and second sources will arrive at this point. Moreover, the phases are opposite.
If the path 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 equal to zero or an integer number of wavelengths, an increase in the amplitude of the resulting wave will be observed at the meeting point. This is an interference pattern when waves from two sources are added.
The frequency of electromagnetic waves is fixed in modern technology. The receiving device must register weak electromagnetic waves. If you put a reflector, more wave energy will enter the receiver. The reflector system is installed so that it creates the maximumsignal on the receiving device.
Characteristics of the wave process underlie modern ideas about the nature of light and the structure of matter. Thus, when studying them in a 9th grade physics textbook, you can successfully learn how to solve problems from the field of mechanics.
