If you are interested in everything related toWhat is a Wave?, in this article you can get information on the subject, how they are created, types of waves, their characteristics, see the wave from the mathematical side and much more.
Definition
When a rock is thrown into a lake, when you sound the string of a musical instrument or turn on a light, physical phenomena with a different nature develop, having something in common: the diffusion of alterations in which there is not a complete sending of matter.
The truth is that all these examples are "wave movements" or "wave propagation". In the following, an approach to this phenomenon of waves will be made, where doubts will be clarified regarding ¿what is a wave? And the differences will be taught and how each of the examples are similar.
Onda means "unda" in Latin. In the area of physics, it is the expansion of a movement of some attribute that comes from space, for example: pressure, density, magnetic or electric field, where a transfer of energy is involved without sending matter (water, air) or also without anything.
Wave Motion Characteristics
The various currents of some bodies moving in one place have already been studied. For example, a car that goes on a course, a box that goes through a flat place with a certain inclination, a planet that is around the structure of the sun.
In all these cases, what is transferred is the mass in the company of linear time and kinetic energy. In wave motion it is different.
The undulating movement or movement of wave propagation is the alteration that is generated from one place to another place without finding any whole body transport, what there is is the transmission of energy.
This concept can be explained with a simple example. When a rock falls into a lake, or you make movements with your finger along the water, an alteration begins. This alteration is what is known as a wave which expands making figures of a ring.
In periodic waves, the peaks or their crests and valleys stand out, and they fall into the category of diagonal or "longitudinal" waves.
The transverse or diagonal ones are those that receive oscillations in a perpendicular way going towards the wave; it can be given for example to a string and electromagnetic waves.
Longitudinal waves are waves with similar oscillations with their diffusion direction; for example, the waves that are emitted by sounds. This type of odes enters the characteristics of the Quantum Planck Theory.
Sine waves are waves that go up and down, for example when an object in a well makes a cut and the wave is produced.
Just as the waves that form in a container are the mixture of longitudinal and transverse waves; flush signals continue the orbital trail.
In general all waves have the same procedure in a number of normal situations. The waves as a whole go through the following phenomena:
- Diffraction: this happens if a wave collides with the edge of an object, it no longer follows its direction straight but begins to corner it.
- Doppler effect": This effect occurs when the movement is a reference between the transmitter of the wave and the one who receives it.
- Interference: It happens when two waves meet at the same point and end up adjusting.
- Reflection: this wave occurs when it is achieved with an unknown medium which is difficult to cross and it only has to change its course.
- Refraction: In this type of wave, it has to change its course when it enters a medium that is different and its speed varies.
- Shock wave: it happens when there are many waves that are transiting in the same medium, joining up to make a kind of cone.
ripples in the water
The alterations that occur in the water is a clear example of what what is a wave. It must be clear that what moves is the alteration, not the water molecules. The water molecules will be jiggling around where their equilibrium is without making a movement of their own.
The example with the piece of cork, which was commented on at the beginning, was in total rest, it is demonstrated how the passage of energy is without the need for the displacement of the agent that motivates the alteration, in this case the stone, which leaves to the bottom of the lake, or the finger, which will continue to be connected to the hand.
With these facts you can summarize some characteristics that waves possess:
It is important that there is a point that emits or begins the alteration. The energy from this point is emitted to the transmission center in its vicinity.
In the case of the rock that falls into the water, or the finger that shakes the water, they carry their power to the molecules of the liquid that are nearby.
There must be a means of diffusion, that while it is crossed by the alteration, it presents a change for a moment which is momentarily variable and can return to its initial state in some of its physical attributes.
This medium acts as a column or emission point for the movement of the waves, although it does not change position.
Continuing with the example of the rock that is thrown into the lake, at the moment that the wave meets the drops of water, which are still, they will begin to make some vibrations, changing their position everywhere where their balance is. .
After a while everything returns to tranquility, in the same way as the cork changes state.
Each place in the middle communicates this alteration to all nearby places. This is how the undulation phenomenon takes place, which is the associated way in which the energy that is transmitted between the center and the places reached is propagated.
As the disturbance spreads, the wave softens. When it is attenuated, it is due to the dosage of the energy that is being generated while the alteration takes over space and grows, other circumstances must also be included, such as the level of elasticity of the medium or the probability of friction between the particles.
At this moment the cork will begin to raise its vibration if it is close to the area where the rock is thrown.
As the rock falls, ripples begin to form and the wave travels as far as it can go, there is a delay.
With this, the finite speed of expansion of the waves becomes visible. In the example above, the cork that is located at a considerable distance from where the rock falls, its state is perturbed in the instant after the rock falls and the wave is formed.
The wave cannot be considered as a tangible medium, but a real physical entity due to the fact that it transfers energy and creates a relationship with the tangible.
You have to understand that the wave is not the rock, nor the water molecules found in the lake, nor the cork. It is quite the opposite, it is the energy that is expanding in that way that is doing it and disturbing the characteristics of the medium.
Waves and Simple Harmonic Motion
Simple Harmonic Motion focuses on the details of a single particle. The power that produces the vibrations that depend on the proportion of where that harmony is found. But you don't focus on what is causing this vibration around you.
It has nothing to do with the energy that is propagated by vibration. Here is shown the difference in the approach of what is studied in waves and what is studied in "simple harmonic motion".
For this reason, it is important to know how to clearly differentiate between two different episodes: the oscillations or also called vibrations of one or several determined particles "movement of matter" and the transfer of an alteration "energy movement" that is the effect of these oscillations.
It may be that a wave causes the particles of the medium to have a balanced and simple movement, when the waves are analyzed the point to study is the emission of the alterations and the movement of an independent particle is not taken into account. This is demonstrated by the example of the rock in the lake.
All the particles of the lake begin to vibrate, in a close way, according to the “mas” (simple harmonic motion), slowing down with time. This can be better understood by imagining the cork repeatedly moving up and down.
In the analyzes of the wave phenomenon, what is important is the expansion of the alteration in a group manner, throughout the lake.
Description of the Waves from the mathematical point of view
To know what a wave is, the example of the rock thrown into the lake is an easy way to understand it, although the difference in perspective in the particles of the medium is not the only physical magnitude that can have variations in the displacement of the waves. .
We must take into account the wave phenomenon that exists in natural sounds, which is one of the most common. The figure that characterizes the wave when an air pressure is made, for example.
Sound is the waves that are in the air
When a megaphone is used, the sound that comes out of it is the transmission of the cyclical variation of the tension exerted by the air, which is around it, causing movement to a fabric that is inside the megaphone.
There are many physical variables that can influence diversification within the environment. As it can be the location of the particles, the tension that is made in the air or the magnetic field, this is when it refers to light.
If we capture the moment in an image of any of these attributes, a particular trait will be obtained that shows how the process of alteration is going in the medium.
After all this you can get to:
When thinking like a mathematician, it is said that a wave is an equation where the elements can be found, which are created by a center that emits it.
y=f(x,t)
The term used above indicates that the wave is a function «f» that gives a particular amount to a variable and includes the coordinate and location of the particles, together with the air tension; than after its spatial location "x" and the instant "t" depending on where it is.
If you want to visualize a wave in a single image, that is not possible, because you cannot appreciate the temporal and spatial process at the same time. The term wave is used in the instantaneous profile of the central alteration.
Wave equation
Not all functions f (x,t) are waves, they must apply the terms of the wave equation. This is already part of another topic, although you can see the statement when it comes to a speed wave «v» if needed.
When there are spatial and temporal variations of the wave, they can be formulated as a sinusoidal function, which has a sine and consine function; with this it is reduced in a giant way as far as the mathematical subject is concerned.
Different Ways to Produce Waves
We can generate waves in two ways:
- By means of a pulse or pulse of waves: it is a particular alteration that can happen when the tip of a cord that is pressed or tense is grabbed and a stretch is given.
- Through a wave train: happens when there is a chain of pulses that create a traveling wave. The perfect example is the moment when a pressed rope is given many tugs, which is clamped at one end. When it comes to waves and references, we are talking about a chain or train of waves.
Wave Types
There are many classifications for waves, it depends on the type of reasoning used. In the following are the most frequent:
Type of propagated energy
Among these are the mechanical and electromagnetic waves.
- mechanical waves: in this type of waves mechanical energy is generated. They also have the name of material waves, because an elastic transmission medium is necessary. As an example there is the sound or the wave that is emitted by the lake in the example of the rock.
- Electromagnetic waves: With this type of waves, electromagnetic energy is generated caused by the oscillations of the electric and magnetic fields. It does not need any type of medium to be generated. The best example for this type of waves is light, the best way of diffusion is the vacuum, which is demonstrated with one of the theorems and Contributions by Blaise Pascal.
- Propagation Direction: They are the waves where there are coincidences in the vibration trajectory with respect to the trajectory in which it is generated. It is understood as a chain of contradictions and dilations. They are also called pressure waves. Sound or a spring can serve as an example.
- Transverse Waves: They are the waves where the path of propagation and vibration are perpendicular to each other. To understand them, it is like a series of peaks that are the maximum and the valleys that would be the minimum. For example, the wave that is generated in the lake, the one that generates a string. These are transverse waves.
- Longitudinal and Transverse Waves: a spring can serve as an example in longitudinal waves and in transverse waves, the arrow indicates the direction in which the alteration is generated. It can be seen how the arrow has the same direction as the path of the vibration of the spring particles, this happens in the process of longitudinal waves. In the process of transverse waves, the path is perpendicular, as indicated by the arrow.
Number of Propagation Dimensions
One Dimensional Waves: In this wave the energy is first dispersed in a space, it can occur, for example, the wave that is generated in a cord.
Two-Dimensional Waves: In this case, the energy is generated primarily in two spaces, like the waves that are generated at the level of the water in a lake.
three dimensional waves: In this type of waves, the energy is first diffused in three dimensions, for example, the wave that is generated in light and sound.
Traveler: the energy that is assigned by the axis that emits it to the medium, progresses in only one direction. They are common in media that are independent and accessible where the diffusion is free of any blockage that is reflected in the wave in the direction of the emitting focus. The sample is the wave that originates when a cord is held in one hand and the other side is free.
Stationary: happens when the energy remains retained in a region of space. They are frequent in media that are closed or with limitations, this makes the wave manifest in the direction of the source that emits it.
These are generated when waves are produced in a cord in which one of its ends is tied to a hand and the other end is fixed. This is also the case in which the two ends are fixed, as in the strings of a musical instrument.
Harmonica: This wave is observed when the spatial and temporal variants can be disclosed by means of sine and cosine functions. Each of the parts of the means of death is executed by a mas
elements of a wave
Cresta: It is the site where it has the greatest elongation or the greatest extension of the wave; It is the place where the wave is furthest from its resting state.
Period: It is the lapse of time that the wave has to make a total oscillation.
Amplitude: It is the vertical path between the crest and the middle of the wave. It should be noted that there are waves which have a variable width, this means, it may be an increase or decrease at the moment.
Frequency: These are the number of times the vibration is repeated for a period of time. Or it is a simple recurrence of values for a stipulated period of time.
Phase: The phase indicates the behavior of the moment in which the cycle is fulfilled, with a size that is periodically variable, being part of the time that has passed since the moment that has been indicated as the beginning of the reference.
Valle: It is the lowest point where the wave can reach.
Wavelength: It is the path that measures the same point of a pair of undulations one after the other. Or what measures the path of two ridges in a row.
Nodes: It is the place where the wave crosses the edge of stability.
Elongation: It is the measurement that appears, perpendicularly, between the point of the wave and the state of equilibrium.
Cycle: It is a simple oscillation, or it can be said that it is the trajectory from the node that begins the path of the crest to the node that culminates the path of the valley, also the opposite.
propagation speed: It is the speed at which the wave motion expands. Having as value the quotient of the length of the wave and its period.