Wave

Surface waves in water showing water ripples
Example of biological waves expanding over the brain cortex, an example of spreading depolarizations.
Wavelength λ, can be measured between any two corresponding points on a waveform
Animation of two waves, the green wave moves to the right while blue wave moves to the left, the net red wave amplitude at each point is the sum of the amplitudes of the individual waves. Note that f(x,t) + g(x,t) = u(x,t)
Sine, square, triangle and sawtooth waveforms.
Amplitude modulation can be achieved through f(x,t) = 1.00×sin(2π/0.10×(x−1.00×t)) and g(x,t) = 1.00×sin(2π/0.11×(x−1.00×t))only the resultant is visible to improve clarity of waveform.
Illustration of the envelope (the slowly varying red curve) of an amplitude-modulated wave. The fast varying blue curve is the carrier wave, which is being modulated.
The red square moves with the phase velocity, while the green circles propagate with the group velocity
A wave with the group and phase velocities going in different directions
Standing wave. The red dots represent the wave nodes
Light beam exhibiting reflection, refraction, transmission and dispersion when encountering a prism
Sinusoidal traveling plane wave entering a region of lower wave velocity at an angle, illustrating the decrease in wavelength and change of direction (refraction) that results.
Identical waves from two sources undergoing interference. Observed at the bottom one sees 5 positions where the waves add in phase, but in between which they are out of phase and cancel.
Schematic of light being dispersed by a prism. Click to see animation.
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Formation of a shock wave by a plane.
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A propagating wave packet; in general, the envelope of the wave packet moves at a different speed than the constituent waves.
Animation showing the effect of a cross-polarized gravitational wave on a ring of test particles
One-dimensional standing waves; the fundamental mode and the first 5 overtones.
A two-dimensional standing wave on a disk; this is the fundamental mode.
A standing wave on a disk with two nodal lines crossing at the center; this is an overtone.

Propagating dynamic disturbance of one or more quantities.

- Wave
Surface waves in water showing water ripples

495 related topics

Relevance

A pendulum making 25 complete oscillations in 60 s, a frequency of 0.41 Hertz

Frequency

Number of occurrences of a repeating event per unit of time.

Number of occurrences of a repeating event per unit of time.

A pendulum making 25 complete oscillations in 60 s, a frequency of 0.41 Hertz
A pendulum with a period of 2.8 s and a frequency of 0.36 Hz
Diagram of the relationship between the different types of frequency and other wave properties.
Modern frequency counter
Complete spectrum of electromagnetic radiation with the visible portion highlighted
The sound wave spectrum, with rough guide of some applications

For cyclical phenomena such as oscillations, waves, or for examples of simple harmonic motion, the term frequency is defined as the number of cycles or vibrations per unit of time.

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Electromagnetic radiation

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Shows the relative wavelengths of the electromagnetic waves of three different colours of light (blue, green, and red) with a distance scale in micrometers along the x-axis.
In electromagnetic radiation (such as microwaves from an antenna, shown here) the term "radiation" applies only to the parts of the electromagnetic field that radiate into infinite space and decrease in intensity by an inverse-square law of power, so that the total radiation energy that crosses through an imaginary spherical surface is the same, no matter how far away from the antenna the spherical surface is drawn. Electromagnetic radiation thus includes the far field part of the electromagnetic field around a transmitter. A part of the "near-field" close to the transmitter, forms part of the changing electromagnetic field, but does not count as electromagnetic radiation.
Electromagnetic waves can be imagined as a self-propagating transverse oscillating wave of electric and magnetic fields. This 3D animation shows a plane linearly polarized wave propagating from left to right. The electric and magnetic fields in such a wave are in-phase with each other, reaching minima and maxima together.
Representation of the electric field vector of a wave of circularly polarized electromagnetic radiation.
James Clerk Maxwell
Electromagnetic spectrum with visible light highlighted
Rough plot of Earth's atmospheric absorption and scattering (or opacity) of various wavelengths of electromagnetic radiation

In physics, electromagnetic radiation (EMR) consists of waves of the electromagnetic (EM) field, propagating through space, carrying electromagnetic radiant energy.

Superposition of almost plane waves (diagonal lines) from a distant source and waves from the wake of the ducks. Linearity holds only approximately in water and only for waves with small amplitudes relative to their wavelengths.

Superposition principle

Sum of the responses that would have been caused by each stimulus individually.

Sum of the responses that would have been caused by each stimulus individually.

Superposition of almost plane waves (diagonal lines) from a distant source and waves from the wake of the ducks. Linearity holds only approximately in water and only for waves with small amplitudes relative to their wavelengths.
Rolling motion as superposition of two motions. The rolling motion of the wheel can be described as a combination of two separate motions: translation without rotation, and rotation without translation.
Two waves traveling in opposite directions across the same medium combine linearly. In this animation, both waves have the same wavelength and the sum of amplitudes results in a standing wave.
two waves permeate without influencing each other
green wave traverse to the right while blue wave traverse left, the net red wave amplitude at each point is the sum of the amplitudes of the individual waves.

Fourier analysis is particularly common for waves.

A pseudocolor image of two people taken in long-wavelength infrared (body-temperature thermal) radiation.

Infrared

Electromagnetic radiation (EMR) with wavelengths longer than those of visible light.

Electromagnetic radiation (EMR) with wavelengths longer than those of visible light.

A pseudocolor image of two people taken in long-wavelength infrared (body-temperature thermal) radiation.
This false-color infrared space telescope image has blue, green and red corresponding to 3.4, 4.6, and 12 μm wavelengths, respectively.
Plot of atmospheric transmittance in part of the infrared region
Materials with higher emissivity appear closer to their true temperature than materials that reflect more of their different-temperature surroundings. In this thermal image, the more reflective ceramic cylinder, reflecting the cooler surroundings, appears to be colder than its cubic container (made of more emissive silicon carbide), while in fact, they have the same temperature.
Active-infrared night vision: the camera illuminates the scene at infrared wavelengths invisible to the human eye. Despite a dark back-lit scene, active-infrared night vision delivers identifying details, as seen on the display monitor.
Thermography helped to determine the temperature profile of the Space Shuttle thermal protection system during re-entry.
Hyperspectral thermal infrared emission measurement, an outdoor scan in winter conditions, ambient temperature −15 °C, image produced with a Specim LWIR hyperspectral imager. Relative radiance spectra from various targets in the image are shown with arrows. The infrared spectra of the different objects such as the watch clasp have clearly distinctive characteristics. The contrast level indicates the temperature of the object.
Infrared light from the LED of a remote control as recorded by a digital camera
Reflected light photograph in various infrared spectra to illustrate the appearance as the wavelength of light changes.
Infrared hair dryer for hair salons, c. 2010s
IR satellite picture of cumulonimbus clouds over the Great Plains of the United States.
The greenhouse effect with molecules of methane, water, and carbon dioxide re-radiating solar heat
Beta Pictoris with its planet Beta Pictoris b, the light-blue dot off-center, as seen in infrared. It combines two images, the inner disc is at 3.6 μm.
An infrared reflectogram of Mona Lisa by Leonardo da Vinci
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Thermographic image of a snake eating a mouse
Infrared radiation was discovered in 1800 by William Herschel.

As a form of electromagnetic radiation, IR propagates energy and momentum, with properties corresponding to both those of a wave and of a particle, the photon.

Animation of a standing wave ( red ) created by the superposition of a left traveling ( blue ) and right traveling ( green ) wave

Standing wave

Animation of a standing wave ( red ) created by the superposition of a left traveling ( blue ) and right traveling ( green ) wave
Longitudinal standing wave
Transient analysis of a damped traveling wave reflecting at a boundary
Standing wave in stationary medium. The red dots represent the wave nodes.
A standing wave (black) depicted as the sum of two propagating waves traveling in opposite directions (red and blue).
Electric force vector (E) and magnetic force vector (H) of a standing wave.
Standing waves in a string – the fundamental mode and the first 5 harmonics.
A standing wave on a circular membrane, an example of standing waves in two dimensions. This is the fundamental mode.
A higher harmonic standing wave on a disk with two nodal lines crossing at the center.

In physics, a standing wave, also known as a stationary wave, is a wave that oscillates in time but whose peak amplitude profile does not move in space.

A diving grebe creates surface waves.

Surface wave

Mechanical wave that propagates along the interface between differing media.

Mechanical wave that propagates along the interface between differing media.

A diving grebe creates surface waves.
The E-field of a surface plasmon polariton at an silver–air interface, at a frequency corresponding to a free-space wavelength of 10μm. At this frequency, the silver behaves approximately as a perfect electric conductor, and the SPP is called a Sommerfeld–Zenneck wave, with almost the same wavelength as the free-space wavelength.

Examples are the waves at the surface of water and air (ocean surface waves).

Wave functions of the electron in a hydrogen atom at different energy levels. Quantum mechanics cannot predict the exact location of a particle in space, only the probability of finding it at different locations. The brighter areas represent a higher probability of finding the electron.

Quantum mechanics

Fundamental theory in physics that provides a description of the physical properties of nature at the scale of atoms and subatomic particles.

Fundamental theory in physics that provides a description of the physical properties of nature at the scale of atoms and subatomic particles.

Wave functions of the electron in a hydrogen atom at different energy levels. Quantum mechanics cannot predict the exact location of a particle in space, only the probability of finding it at different locations. The brighter areas represent a higher probability of finding the electron.
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Position space probability density of a Gaussian wave packet moving in one dimension in free space.
1-dimensional potential energy box (or infinite potential well)
Some trajectories of a harmonic oscillator (i.e. a ball attached to a spring) in classical mechanics (A-B) and quantum mechanics (C-H). In quantum mechanics, the position of the ball is represented by a wave (called the wave function), with the real part shown in blue and the imaginary part shown in red. Some of the trajectories (such as C, D, E, and F) are standing waves (or "stationary states"). Each standing-wave frequency is proportional to a possible energy level of the oscillator. This "energy quantization" does not occur in classical physics, where the oscillator can have any energy.
Schematic of a Mach–Zehnder interferometer.
Max Planck is considered the father of the quantum theory.
The 1927 Solvay Conference in Brussels was the fifth world physics conference.

Quantum mechanics differs from classical physics in that energy, momentum, angular momentum, and other quantities of a bound system are restricted to discrete values (quantization), objects have characteristics of both particles and waves (wave–particle duality), and there are limits to how accurately the value of a physical quantity can be predicted prior to its measurement, given a complete set of initial conditions (the uncertainty principle).

Ripple in water is a surface wave.

Mechanical wave

Ripple in water is a surface wave.

In physics, a mechanical wave is a wave that is an oscillation of matter, and therefore transfers energy through a medium.

The interference of two waves. When in phase, the two lower waves create constructive interference (left), resulting in a wave of greater amplitude. When 180° out of phase, they create destructive interference (right).

Wave interference

The interference of two waves. When in phase, the two lower waves create constructive interference (left), resulting in a wave of greater amplitude. When 180° out of phase, they create destructive interference (right).
Interference of right traveling (green) and left traveling (blue) waves in Two-dimensional space, resulting in final (red) wave
Interference of waves from two point sources.
A magnified image of a coloured interference pattern in a soap film. The "black holes" are areas of almost total destructive interference (antiphase).
Geometrical arrangement for two plane wave interference
Interference fringes in overlapping plane waves
Optical interference between two point sources that have different wavelengths and separations of sources.
Creation of interference fringes by an optical flat on a reflective surface. Light rays from a monochromatic source pass through the glass and reflect off both the bottom surface of the flat and the supporting surface.  The tiny gap between the surfaces means the two reflected rays have different path lengths. In addition the ray reflected from the bottom plate undergoes a 180° phase reversal.  As a result, at locations (a) where the path difference is an odd multiple of λ/2, the waves reinforce.   At locations (b) where the path difference is an even multiple of λ/2 the waves cancel.  Since the gap between the surfaces varies slightly in width at different points, a series of alternating bright and dark bands, interference fringes, are seen.
White light interference in a soap bubble. The iridescence is due to thin-film interference.
The Very Large Array, an interferometric array formed from many smaller telescopes, like many larger radio telescopes.

In physics, interference is a phenomenon in which two waves combine by adding their displacement together at every single point in space and time, to form a resultant wave of greater, lower, or the same amplitude.

The propagation of SV-wave in a homogeneous half-space (The horizontal displacement field)

Wave propagation

The propagation of SV-wave in a homogeneous half-space (The horizontal displacement field)
The propagation of SV-wave in a homogeneous half-space (The vertical displacement field)
Seismic wave propagation in 2D modelled using FDTD method in the presence of a landmine

Wave propagation is any of the ways in which waves travel.