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( May 2014 ) ( Learn how and when to remove this template message ) Part of a series of articles about Quantum mechanics i ħ ∂ ∂ t ψ ( t ) ⟩ = H ^ ψ ( t ) ⟩ ( \ displaystyle i \ hbar ( \ frac ( \ partial ) ( \ partial t ) ) \ psi ( t ) \ rangle = ( \ hat ( H ) ) \ psi ( t ) \ rangle ) Schrödinger equation Introduction Glossary History Background ( show ) Classical mechanics Old quantum theory Bra -- ket notation Hamiltonian Interference Fundamentals ( show ) Casimir effect Coherence Decoherence Complementarity Energy level Entanglement Hamiltonian Uncertainty principle Ground state Interference Measurement Nonlocality Observable Operator Quantum Quantum fluctuation Quantum foam Quantum levitation Quantum number Quantum noise Quantum realm Quantum state Quantum system Quantum teleportation Qubit Spin Superposition Symmetry ( Spontaneous ) symmetry breaking Tunnelling Vacuum state Wave propagation Wave function Wave function collapse Wave -- particle duality Matter wave Experiments ( show ) Afshar Bell 's inequality Davisson -- Germer Double - slit Elitzur -- Vaidman Franck -- Hertz Leggett -- Garg inequality Mach -- Zehnder Popper Quantum eraser ( delayed - choice ) Schrödinger 's cat Quantum suicide and immortality Stern -- Gerlach Wheeler 's delayed - choice Formulations ( show ) Overview Heisenberg Interaction Matrix Phase - space Schrödinger Sum - over-histories ( path integral ) Equations ( show ) Dirac Klein -- Gordon Pauli Rydberg Schrödinger Interpretations ( show ) Overview Consistent histories Copenhagen de Broglie -- Bohm Ensemble Hidden - variable Many - worlds Objective collapse Bayesian Quantum logic Relational Stochastic Scale relativity Transactional Advanced topics ( show ) Quantum annealing Quantum chaos Quantum computing Density matrix Quantum field theory Fractional quantum mechanics Quantum gravity Quantum information science Quantum machine learning Perturbation theory ( quantum mechanics ) Relativistic quantum mechanics Scattering theory Spontaneous parametric down - conversion Quantum statistical mechanics Scientists ( show ) Aharonov Bell Blackett Bloch Bohm Bohr Bose de Broglie Candlin Compton Dirac Davisson Debye Ehrenfest Einstein Everett Fock Fermi Feynman Glauber Gutzwiller Heisenberg Hilbert Jordan Kramers Pauli Lamb Landau Laue Moseley Millikan Onnes Planck Rabi Raman Rydberg Schrödinger Sommerfeld von Neumann Weyl Wien Wigner Zeeman Zeilinger Wave -- particle duality is the concept in quantum mechanics that every particle or quantic entity may be partly described in terms not only of particles , but also of waves . It expresses the inability of the classical concepts `` particle '' or `` wave '' to fully describe the behavior of quantum - scale objects . As Albert Einstein wrote : It seems as though we must use sometimes the one theory and sometimes the other , while at times we may use either . We are faced with a new kind of difficulty . We have two contradictory pictures of reality ; separately neither of them fully explains the phenomena of light , but together they do . Through the work of Max Planck , Albert Einstein , Louis de Broglie , Arthur Compton , Niels Bohr and many others , current scientific theory holds that all particles also have a wave nature ( and vice versa ) . This phenomenon has been verified not only for elementary particles , but also for compound particles like atoms and even molecules . For macroscopic particles , because of their extremely short wavelengths , wave properties usually can not be detected . Although the use of the wave - particle duality has worked well in physics , the meaning or interpretation has not been satisfactorily resolved ; see Interpretations of quantum mechanics . Bohr regarded the `` duality paradox '' as a fundamental or metaphysical fact of nature . A given kind of quantum object will exhibit sometimes wave , sometimes particle , character , in respectively different physical settings . He saw such duality as one aspect of the concept of complementarity . Bohr regarded renunciation of the cause - effect relation , or complementarity , of the space - time picture , as essential to the quantum mechanical account . Werner Heisenberg considered the question further . He saw the duality as present for all quantic entities , but not quite in the usual quantum mechanical account considered by Bohr . He saw it in what is called second quantization , which generates an entirely new concept of fields which exist in ordinary space - time , causality still being visualizable . Classical field values ( e.g. the electric and magnetic field strengths of Maxwell ) are replaced by an entirely new kind of field value , as considered in quantum field theory . Turning the reasoning around , ordinary quantum mechanics can be deduced as a specialized consequence of quantum field theory . Contents ( hide ) 1 Brief history of wave and particle viewpoints 2 Turn of the 20th century and the paradigm shift 2.1 Particles of electricity 2.2 Radiation quantization 2.3 Photoelectric effect illuminated 2.4 Einstein 's explanation of the photoelectric effect 2.5 De Broglie 's wavelength 2.6 Heisenberg 's uncertainty principle 2.7 de Broglie -- Bohm theory 3 Wave behavior of large objects 4 Treatment in modern quantum mechanics 4.1 Visualization 5 Alternative views 5.1 Both - particle - and - wave view 5.2 Wave - only view 5.3 Particle - only view 5.4 Neither - wave - nor - particle view 5.5 Relational approach to wave -- particle duality 6 Applications 7 See also 8 Notes and references 9 External links Brief History of wave and particle viewpoints ( edit ) Democritus -- the original atomist -- argued that all things in the universe , including light , are composed of indivisible sub-components ( light being some form of solar atom ) . At the beginning of the 11th Century , the Arabic scientist Alhazen wrote the first comprehensive treatise on optics ; describing refraction , reflection , and the operation of a pinhole lens via rays of light traveling from the point of emission to the eye . He asserted that these rays were composed of particles of light . In 1630 , René Descartes popularized and accredited the opposing wave description in his treatise on light , showing that the behavior of light could be re-created by modeling wave - like disturbances in a universal medium ( `` plenum '' ) . Beginning in 1670 and progressing over three decades , Isaac Newton developed and championed his corpuscular hypothesis , arguing that the perfectly straight lines of reflection demonstrated light 's particle nature ; only particles could travel in such straight lines . He explained refraction by positing that particles of light accelerated laterally upon entering a denser medium . Around the same time , Newton 's contemporaries Robert Hooke and Christiaan Huygens -- and later Augustin - Jean Fresnel -- mathematically refined the wave viewpoint , showing that if light traveled at different speeds in different media ( such as water and air ) , refraction could be easily explained as the medium - dependent propagation of light waves . The resulting Huygens -- Fresnel principle was extremely successful at reproducing light 's behavior and was subsequently supported by Thomas Young 's 1801 discovery of double - slit interference . The wave view did not immediately displace the ray and particle view , but began to dominate scientific thinking about light in the mid 19th century , since it could explain polarization phenomena that the alternatives could not . Thomas Young 's sketch of two - slit diffraction of waves , 1803 James Clerk Maxwell discovered that he could apply his equations for electromagnetism , which had been previously discovered , along with a slight modification to describe self - propagating waves of oscillating electric and magnetic fields . It quickly became apparent that visible light , ultraviolet light , and infrared light ( phenomena thought previously to be unrelated ) were all electromagnetic waves of differing frequency . The wave theory had prevailed -- or at least it seemed to . While the 19th century had seen the success of the wave theory at describing light , it had also witnessed the rise of the atomic theory at describing matter . Antoine Lavoisier deduced the law of conservation of mass and categorized many new chemical elements and compounds ; and Joseph Louis Proust advanced chemistry towards the atom by showing that elements combined in definite proportions . This led John Dalton to propose that elements were invisible sub components ; Amedeo Avogadro discovered diatomic gases and completed the basic atomic theory , allowing the correct molecular formulae of most known compounds -- as well as the correct weights of atoms -- to be deduced and categorized in a consistent manner . Dimitri Mendeleev saw an order in recurring chemical properties , and created a table presenting the elements in unprecedented order and symmetry . Play media Animation showing the wave - particle duality with a double slit experiment and effect of an observer . Increase size to see explanations in the video itself . See also quiz based on this animation . Particle impacts make visible the interference pattern of waves . A quantum particle is represented by a wave packet . Interference of a quantum particle with itself . Click images for animations . Turn of the 20th century and the paradigm shift ( edit ) Particles of electricity ( edit ) At the close of the 19th century , the reductionism of atomic theory began to advance into the atom itself ; determining , through physics , the nature of the atom and the operation of chemical reactions . Electricity , first thought to be a fluid , was now understood to consist of particles called electrons . This was first demonstrated by J.J. Thomson in 1897 when , using a cathode ray tube , he found that an electrical charge would travel across a vacuum ( which would possess infinite resistance in classical theory ) . Since the vacuum offered no medium for an electric fluid to travel , this discovery could only be explained via a particle carrying a negative charge and moving through the vacuum . This electron flew in the face of classical electrodynamics , which had successfully treated electricity as a fluid for many years ( leading to the invention of batteries , electric motors , dynamos , and arc lamps ) . More importantly , the intimate relation between electric charge and electromagnetism had been well documented following the discoveries of Michael Faraday and James Clerk Maxwell . Since electromagnetism was known to be a wave generated by a changing electric or magnetic field ( a continuous , wave - like entity itself ) an atomic / particle description of electricity and charge was a non sequitur . Furthermore , classical electrodynamics was not the only classical theory rendered incomplete . Radiation quantization ( edit ) Main article : Planck 's law In 1901 , Max Planck published an analysis that succeeded in reproducing the observed spectrum of light emitted by a glowing object . To accomplish this , Planck had to make an ad hoc mathematical assumption of quantized energy of the oscillators ( atoms of the black body ) that emit radiation . Einstein later proposed that electromagnetic radiation itself is quantized , not the energy of radiating atoms . Black - body radiation , the emission of electromagnetic energy due to an object 's heat , could not be explained from classical arguments alone . The equipartition theorem of classical mechanics , the basis of all classical thermodynamic theories , stated that an object 's energy is partitioned equally among the object 's vibrational modes . But applying the same reasoning to the electromagnetic emission of such a thermal object was not so successful . That thermal objects emit light had been long known . Since light was known to be waves of electromagnetism , physicists hoped to describe this emission via classical laws . This became known as the black body problem . Since the equipartition theorem worked so well in describing the vibrational modes of the thermal object itself , it was natural to assume that it would perform equally well in describing the radiative emission of such objects . But a problem quickly arose : if each mode received an equal partition of energy , the short wavelength modes would consume all the energy . This became clear when plotting the Rayleigh -- Jeans law which , while correctly predicting the intensity of long wavelength emissions , predicted infinite total energy as the intensity diverges to infinity for short wavelengths . This became known as the ultraviolet catastrophe . In 1900 , Max Planck hypothesized that the frequency of light emitted by the black body depended on the frequency of the oscillator that emitted it , and the energy of these oscillators increased linearly with frequency ( according to his constant h , where E = hν ) . This was not an unsound proposal considering that macroscopic oscillators operate similarly : when studying five simple harmonic oscillators of equal amplitude but different frequency , the oscillator with the highest frequency possesses the highest energy ( though this relationship is not linear like Planck 's ) . By demanding that high - frequency light must be emitted by an oscillator of equal frequency , and further requiring that this oscillator occupy higher energy than one of a lesser frequency , Planck avoided any catastrophe ; giving an equal partition to high - frequency oscillators produced successively fewer oscillators and less emitted light . And as in the Maxwell -- Boltzmann distribution , the low - frequency , low - energy oscillators were suppressed by the onslaught of thermal jiggling from higher energy oscillators , which necessarily increased their energy and frequency . The most revolutionary aspect of Planck 's treatment of the black body is that it inherently relies on an integer number of oscillators in thermal equilibrium with the electromagnetic field . These oscillators give their entire energy to the electromagnetic field , creating a quantum of light , as often as they are excited by the electromagnetic field , absorbing a quantum of light and beginning to oscillate at the corresponding frequency . Planck had intentionally created an atomic theory of the black body , but had unintentionally generated an atomic theory of light , where the black body never generates quanta of light at a given frequency with an energy less than hν . However , once realizing that he had quantized the electromagnetic field , he denounced particles of light as a limitation of his approximation , not a property of reality . Photoelectric effect illuminated ( edit ) While Planck had solved the ultraviolet catastrophe by using atoms and a quantized electromagnetic field , most contemporary physicists agreed that Planck 's `` light quanta '' represented only flaws in his model . A more - complete derivation of black body radiation would yield a fully continuous and ' wave - like ' electromagnetic field with no quantization . However , in 1905 Albert Einstein took Planck 's black body model to produce his solution to another outstanding problem of the day : the photoelectric effect , wherein electrons are emitted from atoms when they absorb energy from light . Since their existence was theorized eight years previously , phenomenon had been studied with the electron model in mind in physics laboratories worldwide . In 1902 Philipp Lenard discovered that the energy of these ejected electrons did not depend on the intensity of the incoming light , but instead on its frequency . So if one shines a little low - frequency light upon a metal , a few low energy electrons are ejected . If one now shines a very intense beam of low - frequency light upon the same metal , a whole slew of electrons are ejected ; however they possess the same low energy , there are merely more of them . The more light there is , the more electrons are ejected . Whereas in order to get high energy electrons , one must illuminate the metal with high - frequency light . Like blackbody radiation , this was at odds with a theory invoking continuous transfer of energy between radiation and matter . However , it can still be explained using a fully classical description of light , as long as matter is quantum mechanical in nature . If one used Planck 's energy quanta , and demanded that electromagnetic radiation at a given frequency could only transfer energy to matter in integer multiples of an energy quantum hν , then the photoelectric effect could be explained very simply . Low - frequency light only ejects low - energy electrons because each electron is excited by the absorption of a single photon . Increasing the intensity of the low - frequency light ( increasing the number of photons ) only increases the number of excited electrons , not their energy , because the energy of each photon remains low . Only by increasing the frequency of the light , and thus increasing the energy of the photons , can one eject electrons with higher energy . Thus , using Planck 's constant h to determine the energy of the photons based upon their frequency , the energy of ejected electrons should also increase linearly with frequency ; the gradient of the line being Planck 's constant . These results were not confirmed until 1915 , when Robert Andrews Millikan , who had previously determined the charge of the electron , produced experimental results in perfect accord with Einstein 's predictions . While the energy of ejected electrons reflected Planck 's constant , the existence of photons was not explicitly proven until the discovery of the photon antibunching effect , of which a modern experiment can be performed in undergraduate - level labs . This phenomenon could only be explained via photons , and not through any semi-classical theory ( which could alternatively explain the photoelectric effect ) . When Einstein received his Nobel Prize in 1921 , it was not for his more difficult and mathematically laborious special and general relativity , but for the simple , yet totally revolutionary , suggestion of quantized light . Einstein 's `` light quanta '' would not be called photons until 1925 , but even in 1905 they represented the quintessential example of wave - particle duality . Electromagnetic radiation propagates following linear wave equations , but can only be emitted or absorbed as discrete elements , thus acting as a wave and a particle simultaneously . Einstein 's explanation of the photoelectric effect ( edit ) Main article : Photoelectric effect The photoelectric effect . Incoming photons on the left strike a metal plate ( bottom ) , and eject electrons , depicted as flying off to the right . In 1905 , Albert Einstein provided an explanation of the photoelectric effect , a hitherto troubling experiment that the wave theory of light seemed incapable of explaining . He did so by postulating the existence of photons , quanta of light energy with particulate qualities . In the photoelectric effect , it was observed that shining a light on certain metals would lead to an electric current in a circuit . Presumably , the light was knocking electrons out of the metal , causing current to flow . However , using the case of potassium as an example , it was also observed that while a dim blue light was enough to cause a current , even the strongest , brightest red light available with the technology of the time caused no current at all . According to the classical theory of light and matter , the strength or amplitude of a light wave was in proportion to its brightness : a bright light should have been easily strong enough to create a large current . Yet , oddly , this was not so . Einstein explained this enigma by postulating that the electrons can receive energy from electromagnetic field only in discrete portions ( quanta that were called photons ) : an amount of energy E that was related to the frequency f of the light by E = h f ( \ displaystyle E = hf \ , ) where h is Planck 's constant ( 6.626 × 10 J seconds ) . Only photons of a high enough frequency ( above a certain threshold value ) could knock an electron free . For example , photons of blue light had sufficient energy to free an electron from the metal , but photons of red light did not . One photon of light above the threshold frequency could release only one electron ; the higher the frequency of a photon , the higher the kinetic energy of the emitted electron , but no amount of light ( using technology available at the time ) below the threshold frequency could release an electron . To `` violate '' this law would require extremely high - intensity lasers which had not yet been invented . Intensity - dependent phenomena have now been studied in detail with such lasers . Einstein was awarded the Nobel Prize in Physics in 1921 for his discovery of the law of the photoelectric effect . De Broglie 's wavelength ( edit ) Main article : Matter wave Propagation of de Broglie waves in 1d -- real part of the complex amplitude is blue , imaginary part is green . The probability ( shown as the colour opacity ) of finding the particle at a given point x is spread out like a waveform ; there is no definite position of the particle . As the amplitude increases above zero the curvature decreases , so the amplitude decreases again , and vice versa -- the result is an alternating amplitude : a wave . Top : Plane wave . Bottom : Wave packet . In 1924 , Louis - Victor de Broglie formulated the de Broglie hypothesis , claiming that all matter , not just light , has a wave - like nature ; he related wavelength ( denoted as λ ) , and momentum ( denoted as p ) : λ = h p ( \ displaystyle \ lambda = ( \ frac ( h ) ( p ) ) ) This is a generalization of Einstein 's equation above , since the momentum of a photon is given by p = E c ( \ displaystyle ( \ tfrac ( E ) ( c ) ) ) and the wavelength ( in a vacuum ) by λ = c f ( \ displaystyle ( \ tfrac ( c ) ( f ) ) ) , where c is the speed of light in vacuum . De Broglie 's formula was confirmed three years later for electrons ( which differ from photons in having a rest mass ) with the observation of electron diffraction in two independent experiments . At the University of Aberdeen , George Paget Thomson passed a beam of electrons through a thin metal film and observed the predicted interference patterns . At Bell Labs , Clinton Joseph Davisson and Lester Halbert Germer guided their beam through a crystalline grid . De Broglie was awarded the Nobel Prize for Physics in 1929 for his hypothesis . Thomson and Davisson shared the Nobel Prize for Physics in 1937 for their experimental work . Heisenberg 's uncertainty principle ( edit ) Main article : Heisenberg uncertainty principle In his work on formulating quantum mechanics , Werner Heisenberg postulated his uncertainty principle , which states : Δ x Δ p ≥ 1 2 ħ ( \ displaystyle \ Delta x \ , \ Delta p \ geq ( \ tfrac ( 1 ) ( 2 ) ) \ hbar ) where Δ ( \ displaystyle \ Delta ) here indicates standard deviation , a measure of spread or uncertainty ; x and p are a particle 's position and linear momentum respectively . ħ ( \ displaystyle \ hbar ) is the reduced Planck 's constant ( Planck 's constant divided by 2 π ( \ displaystyle \ pi ) ) . Heisenberg originally explained this as a consequence of the process of measuring : Measuring position accurately would disturb momentum and vice versa , offering an example ( the `` gamma - ray microscope '' ) that depended crucially on the de Broglie hypothesis . The thought is now , however , that this only partly explains the phenomenon , but that the uncertainty also exists in the particle itself , even before the measurement is made . In fact , the modern explanation of the uncertainty principle , extending the Copenhagen interpretation first put forward by Bohr and Heisenberg , depends even more centrally on the wave nature of a particle : Just as it is nonsensical to discuss the precise location of a wave on a string , particles do not have perfectly precise positions ; likewise , just as it is nonsensical to discuss the wavelength of a `` pulse '' wave traveling down a string , particles do not have perfectly precise momenta ( which corresponds to the inverse of wavelength ) . Moreover , when position is relatively well defined , the wave is pulse - like and has a very ill - defined wavelength ( and thus momentum ) . And conversely , when momentum ( and thus wavelength ) is relatively well defined , the wave looks long and sinusoidal , and therefore it has a very ill - defined position . De Broglie -- Bohm theory ( edit ) Couder experiments , `` materializing '' the pilot wave model . De Broglie himself had proposed a pilot wave construct to explain the observed wave - particle duality . In this view , each particle has a well - defined position and momentum , but is guided by a wave function derived from Schrödinger 's equation . The pilot wave theory was initially rejected because it generated non-local effects when applied to systems involving more than one particle . Non-locality , however , soon became established as an integral feature of quantum theory ( see EPR paradox ) , and David Bohm extended de Broglie 's model to explicitly include it . In the resulting representation , also called the de Broglie -- Bohm theory or Bohmian mechanics , the wave - particle duality vanishes , and explains the wave behaviour as a scattering with wave appearance , because the particle 's motion is subject to a guiding equation or quantum potential . `` This idea seems to me so natural and simple , to resolve the wave - particle dilemma in such a clear and ordinary way , that it is a great mystery to me that it was so generally ignored '' , J.S. Bell . The best illustration of the pilot - wave model was given by Couder 's 2010 `` walking droplets '' experiments , demonstrating the pilot - wave behaviour in a macroscopic mechanical analog . Wave behavior of large objects ( edit ) Since the demonstrations of wave - like properties in photons and electrons , similar experiments have been conducted with neutrons and protons . Among the most famous experiments are those of Estermann and Otto Stern in 1929 . Authors of similar recent experiments with atoms and molecules , described below , claim that these larger particles also act like waves . A dramatic series of experiments emphasizing the action of gravity in relation to wave -- particle duality was conducted in the 1970s using the neutron interferometer . Neutrons , one of the components of the atomic nucleus , provide much of the mass of a nucleus and thus of ordinary matter . In the neutron interferometer , they act as quantum - mechanical waves directly subject to the force of gravity . While the results were not surprising since gravity was known to act on everything , including light ( see tests of general relativity and the Pound -- Rebka falling photon experiment ) , the self - interference of the quantum mechanical wave of a massive fermion in a gravitational field had never been experimentally confirmed before . In 1999 , the diffraction of C fullerenes by researchers from the University of Vienna was reported . Fullerenes are comparatively large and massive objects , having an atomic mass of about 720 u . The de Broglie wavelength of the incident beam was about 2.5 pm , whereas the diameter of the molecule is about 1 nm , about 400 times larger . In 2012 , these far - field diffraction experiments could be extended to phthalocyanine molecules and their heavier derivatives , which are composed of 58 and 114 atoms respectively . In these experiments the build - up of such interference patterns could be recorded in real time and with single molecule sensitivity . In 2003 , the Vienna group also demonstrated the wave nature of tetraphenylporphyrin -- a flat biodye with an extension of about 2 nm and a mass of 614 u . For this demonstration they employed a near - field Talbot Lau interferometer . In the same interferometer they also found interference fringes for C F , a fluorinated buckyball with a mass of about 1600 u , composed of 108 atoms . Large molecules are already so complex that they give experimental access to some aspects of the quantum - classical interface , i.e. , to certain decoherence mechanisms . In 2011 , the interference of molecules as heavy as 6910 u could be demonstrated in a Kapitza -- Dirac -- Talbot -- Lau interferometer . In 2013 , the interference of molecules beyond 10,000 u has been demonstrated . Whether objects heavier than the Planck mass ( about the weight of a large bacterium ) have a de Broglie wavelength is theoretically unclear and experimentally unreachable ; above the Planck mass a particle 's Compton wavelength would be smaller than the Planck length and its own Schwarzschild radius , a scale at which current theories of physics may break down or need to be replaced by more general ones . Recently Couder , Fort , et al. showed that we can use macroscopic oil droplets on a vibrating surface as a model of wave -- particle duality -- localized droplet creates periodical waves around and interaction with them leads to quantum - like phenomena : interference in double - slit experiment , unpredictable tunneling ( depending in complicated way on practically hidden state of field ) , orbit quantization ( that particle has to ' find a resonance ' with field perturbations it creates -- after one orbit , its internal phase has to return to the initial state ) and Zeeman effect . Treatment in modern quantum mechanics ( edit ) Wave -- particle duality is deeply embedded into the foundations of quantum mechanics . In the formalism of the theory , all the information about a particle is encoded in its wave function , a complex - valued function roughly analogous to the amplitude of a wave at each point in space . This function evolves according to a differential equation ( generically called the Schrödinger equation ) . For particles with mass this equation has solutions that follow the form of the wave equation . Propagation of such waves leads to wave - like phenomena such as interference and diffraction . Particles without mass , like photons , have no solutions of the Schrödinger equation so have another wave . The particle - like behavior is most evident due to phenomena associated with measurement in quantum mechanics . Upon measuring the location of the particle , the particle will be forced into a more localized state as given by the uncertainty principle . When viewed through this formalism , the measurement of the wave function will randomly `` collapse '' , or rather `` decohere '' , to a sharply peaked function at some location . For particles with mass the likelihood of detecting the particle at any particular location is equal to the squared amplitude of the wave function there . The measurement will return a well - defined position , ( subject to uncertainty ) , a property traditionally associated with particles . It is important to note that a measurement is only a particular type of interaction where some data is recorded and the measured quantity is forced into a particular eigenstate . The act of measurement is therefore not fundamentally different from any other interaction . Following the development of quantum field theory the ambiguity disappeared . The field permits solutions that follow the wave equation , which are referred to as the wave functions . The term particle is used to label the irreducible representations of the Lorentz group that are permitted by the field . An interaction as in a Feynman diagram is accepted as a calculationally convenient approximation where the outgoing legs are known to be simplifications of the propagation and the internal lines are for some order in an expansion of the field interaction . Since the field is non-local and quantized , the phenomena which previously were thought of as paradoxes are explained . Within the limits of the wave - particle duality the quantum field theory gives the same results . Visualization ( edit ) There are two ways to visualize the wave - particle behaviour : by the `` standard model '' , described below ; and by the Broglie -- Bohm model , where no duality is perceived . Below is an illustration of wave -- particle duality as it relates to De Broglie 's hypothesis and Heisenberg 's uncertainty principle ( above ) , in terms of the position and momentum space wavefunctions for one spinless particle with mass in one dimension . These wavefunctions are Fourier transforms of each other . The more localized the position - space wavefunction , the more likely the particle is to be found with the position coordinates in that region , and correspondingly the momentum - space wavefunction is less localized so the possible momentum components the particle could have are more widespread . Conversely the more localized the momentum - space wavefunction , the more likely the particle is to be found with those values of momentum components in that region , and correspondingly the less localized the position - space wavefunction , so the position coordinates the particle could occupy are more widespread . Position x and momentum p wavefunctions corresponding to quantum particles . The colour opacity ( % ) of the particles corresponds to the probability density of finding the particle with position x or momentum component p . Top : If wavelength λ is unknown , so are momentum p , wave - vector k and energy E ( de Broglie relations ) . As the particle is more localized in position space , Δx is smaller than for Δp . Bottom : If λ is known , so are p , k , and E. As the particle is more localized in momentum space , Δp is smaller than for Δx . Alternative views ( edit ) Wave -- particle duality is an ongoing conundrum in modern physics . Most physicists accept wave - particle duality as the best explanation for a broad range of observed phenomena ; however , it is not without controversy . Alternative views are also presented here . These views are not generally accepted by mainstream physics , but serve as a basis for valuable discussion within the community . Both - particle - and - wave view ( edit ) The pilot wave model , originally developed by Louis de Broglie and further developed by David Bohm into the hidden variable theory proposes that there is no duality , but rather a system exhibits both particle properties and wave properties simultaneously , and particles are guided , in a deterministic fashion , by the pilot wave ( or its `` quantum potential '' ) which will direct them to areas of constructive interference in preference to areas of destructive interference . This idea is held by a significant minority within the physics community . At least one physicist considers the `` wave - duality '' as not being an incomprehensible mystery . L.E. Ballentine , Quantum Mechanics , A Modern Development , p. 4 , explains : When first discovered , particle diffraction was a source of great puzzlement . Are `` particles '' really `` waves ? '' In the early experiments , the diffraction patterns were detected holistically by means of a photographic plate , which could not detect individual particles . As a result , the notion grew that particle and wave properties were mutually incompatible , or complementary , in the sense that different measurement apparatuses would be required to observe them . That idea , however , was only an unfortunate generalization from a technological limitation . Today it is possible to detect the arrival of individual electrons , and to see the diffraction pattern emerge as a statistical pattern made up of many small spots ( Tonomura et al. , 1989 ) . Evidently , quantum particles are indeed particles , but whose behaviour is very different from classical physics would have us to expect . The Afshar experiment ( 2007 ) may suggest that it is possible to simultaneously observe both wave and particle properties of photons . This claim is , however , disputed by other scientists . Wave - only view ( edit ) Carver Mead , an American scientist and professor at Caltech , proposes that the duality can be replaced by a `` wave - only '' view . In his book Collective Electrodynamics : Quantum Foundations of Electromagnetism ( 2000 ) , Mead purports to analyze the behavior of electrons and photons purely in terms of electron wave functions , and attributes the apparent particle - like behavior to quantization effects and eigenstates . According to reviewer David Haddon : Mead has cut the Gordian knot of quantum complementarity . He claims that atoms , with their neutrons , protons , and electrons , are not particles at all but pure waves of matter . Mead cites as the gross evidence of the exclusively wave nature of both light and matter the discovery between 1933 and 1996 of ten examples of pure wave phenomena , including the ubiquitous laser of CD players , the self - propagating electrical currents of superconductors , and the Bose -- Einstein condensate of atoms . Albert Einstein , who , in his search for a Unified Field Theory , did not accept wave - particle duality , wrote : This double nature of radiation ( and of material corpuscles ) ... has been interpreted by quantum - mechanics in an ingenious and amazingly successful fashion . This interpretation ... appears to me as only a temporary way out ... The many - worlds interpretation ( MWI ) is sometimes presented as a waves - only theory , including by its originator , Hugh Everett who referred to MWI as `` the wave interpretation '' . The three wave hypothesis of R. Horodecki relates the particle to wave . The hypothesis implies that a massive particle is an intrinsically spatially , as well as temporally extended , wave phenomenon by a nonlinear law . Particle - only view ( edit ) Still in the days of the old quantum theory , a pre-quantum - mechanical version of wave -- particle duality was pioneered by William Duane , and developed by others including Alfred Landé . Duane explained diffraction of x-rays by a crystal in terms solely of their particle aspect . The deflection of the trajectory of each diffracted photon was explained as due to quantized momentum transfer from the spatially regular structure of the diffracting crystal . Neither - wave - nor - particle view ( edit ) It has been argued that there are never exact particles or waves , but only some compromise or intermediate between them . For this reason , in 1928 Arthur Eddington coined the name `` wavicle '' to describe the objects although it is not regularly used today . One consideration is that zero - dimensional mathematical points can not be observed . Another is that the formal representation of such points , the Dirac delta function is unphysical , because it can not be normalized . Parallel arguments apply to pure wave states . Roger Penrose states : `` Such ' position states ' are idealized wavefunctions in the opposite sense from the momentum states . Whereas the momentum states are infinitely spread out , the position states are infinitely concentrated . Neither is normalizable ( ... ) . '' Relational approach to wave -- particle duality ( edit ) Relational quantum mechanics has been developed as a point of view that regards the event of particle detection as having established a relationship between the quantized field and the detector . The inherent ambiguity associated with applying Heisenberg 's uncertainty principle is consequently avoided ; hence there is no wave - particle duality . Applications ( edit ) Although it is difficult to draw a line separating wave -- particle duality from the rest of quantum mechanics , it is nevertheless possible to list some applications of this basic idea . Wave -- particle duality is exploited in electron microscopy , where the small wavelengths associated with the electron can be used to view objects much smaller than what is visible using visible light . Similarly , neutron diffraction uses neutrons with a wavelength of about 0.1 nm , the typical spacing of atoms in a solid , to determine the structure of solids . Photos are now able to show this dual nature , which may lead to new ways of examining and recording this behaviour . See also ( edit ) Arago spot Afshar experiment Basic concepts of quantum mechanics Complementarity ( physics ) Englert -- Greenberger -- Yasin duality relation Kapitsa -- Dirac effect Electron wave - packet interference Faraday wave Hanbury Brown and Twiss effect Photon polarization Scattering theory Wavelet Wheeler 's delayed choice experiment Notes and references ( edit ) Jump up ^ Harrison , David ( 2002 ) . `` Complementarity and the Copenhagen Interpretation of Quantum Mechanics '' . UPSCALE . Dept. of Physics , U. of Toronto . Retrieved 2008 - 06 - 21 . Jump up ^ Walter Greiner ( 2001 ) . Quantum Mechanics : An Introduction . Springer . ISBN 3 - 540 - 67458 - 6 . Jump up ^ R. Eisberg & R. Resnick ( 1985 ) . Quantum Physics of Atoms , Molecules , Solids , Nuclei , and Particles ( 2nd ed . ) . John Wiley & Sons . pp. 59 -- 60 . ISBN 047187373X . For both large and small wavelengths , both matter and radiation have both particle and wave aspects ... But the wave aspects of their motion become more difficult to observe as their wavelengths become shorter ... For ordinary macroscopic particles the mass is so large that the momentum is always sufficiently large to make the de Broglie wavelength small enough to be beyond the range of experimental detection , and classical mechanics reigns supreme . Jump up ^ Kumar , Manjit ( 2011 ) . Quantum : Einstein , Bohr , and the Great Debate about the Nature of Reality ( Reprint ed . ) . W.W. Norton & Company . pp. 242 , 375 -- 376 . ISBN 978 - 0393339888 . Jump up ^ Bohr , N. ( 1927 / 1928 ) . The quantum postulate and the recent development of atomic theory , Nature Supplement April 14 1928 , 121 : 580 -- 590 . Jump up ^ Camilleri , K. ( 2009 ) . Heisenberg and the Interpretation of Quantum Mechanics : the Physicist as Philosopher , Cambridge University Press , Cambridge UK , ISBN 978 - 0 - 521 - 88484 - 6 . Jump up ^ Preparata , G. ( 2002 ) . An Introduction to a Realistic Quantum Physics , World Scientific , River Edge NJ , ISBN 978 - 981 - 238 - 176 - 7 . Jump up ^ Nathaniel Page Stites , M.A. / M.S. `` Light I : Particle or Wave ? , '' Visionlearning Vol . PHY - 1 ( 3 ) , 2005 . http://www.visionlearning.com/library/module_viewer.php?mid=132 Jump up ^ Young , Thomas ( 1804 ) . `` Bakerian Lecture : Experiments and calculations relative to physical optics '' . Philosophical Transactions of the Royal Society . 94 : 1 -- 16 . Bibcode : 1804RSPT ... 94 ... 1Y . doi : 10.1098 / rstl. 1804.0001 . Jump up ^ Thomas Young : The Double Slit Experiment Jump up ^ Buchwald , Jed ( 1989 ) . The Rise of the Wave Theory of Light : Optical Theory and Experiment in the Early Nineteenth Century . Chicago : University of Chicago Press . ISBN 0 - 226 - 07886 - 8 . OCLC 18069573 . Jump up ^ Lamb , Willis E. ; Scully , Marlan O. ( 1968 ) . `` The photoelectric effect without photons '' ( PDF ) . Jump up ^ `` Observing the quantum behavior of light in an undergraduate laboratory '' . American Journal of Physics. 72 : 1210 . Bibcode : 2004AmJPh ... 72.1210 T . doi : 10.1119 / 1.1737397 . Jump up ^ Zhang , Q ( 1996 ) . `` Intensity dependence of the photoelectric effect induced by a circularly polarized laser beam '' . Physics Letters A. 216 ( 1 -- 5 ) : 125 -- 128 . Bibcode : 1996PhLA ... 216 ... 125Z . doi : 10.1016 / 0375 - 9601 ( 96 ) 00259 - 9 . Jump up ^ Donald H Menzel , `` Fundamental formulas of Physics '' , volume 1 , page 153 ; Gives the de Broglie wavelengths for composite particles such as protons and neutrons . Jump up ^ Brian Greene , The Elegant Universe , page 104 `` all matter has a wave - like character '' ^ Jump up to : See this Science Channel production ( Season II , Episode VI `` How Does The Universe Work ? '' ) , presented by Morgan Freeman , https://www.youtube.com/watch?v=W9yWv5dqSKk Jump up ^ Bohmian Mechanics , Stanford Encyclopedia of Philosophy . Jump up ^ Bell , J.S. , `` Speakable and Unspeakable in Quantum Mechanics '' , Cambridge : Cambridge University Press , 1987 . Jump up ^ Y . Couder , A. Boudaoud , S. Protière , Julien Moukhtar , E. Fort : Walking droplets : a form of wave - particle duality at macroscopic level ? , doi : 10.1051 / epn / 2010101 , ( PDF ) Jump up ^ Estermann , I. ; Stern O. ( 1930 ) . `` Beugung von Molekularstrahlen '' . Zeitschrift für Physik. 61 ( 1 -- 2 ) : 95 -- 125 . Bibcode : 1930ZPhy ... 61 ... 95E . doi : 10.1007 / BF01340293 . Jump up ^ R. Colella , A.W. Overhauser and S.A. Werner , Observation of Gravitationally Induced Quantum Interference , Phys. Rev. Lett. 34 , 1472 -- 1474 ( 1975 ) . Jump up ^ Arndt , Markus ; O. Nairz ; J. Voss - Andreae , C. Keller , G. van der Zouw , A. Zeilinger ( 14 October 1999 ) . `` Wave -- particle duality of C '' . Nature . 401 ( 6754 ) : 680 -- 682 . Bibcode : 1999Natur. 401 ... 680A . doi : 10.1038 / 44348 . PMID 18494170 . CS1 maint : Multiple names : authors list ( link ) Jump up ^ Juffmann , Thomas ; et al. ( 25 March 2012 ) . `` Real - time single - molecule imaging of quantum interference '' . Nature Nanotechnology . Retrieved 27 March 2012 . Jump up ^ Quantumnanovienna . `` Single molecules in a quantum interference movie '' . Retrieved 2012 - 04 - 21 . ^ Jump up to : Hackermüller , Lucia ; Stefan Uttenthaler ; Klaus Hornberger ; Elisabeth Reiger ; Björn Brezger ; Anton Zeilinger ; Markus Arndt ( 2003 ) . `` The wave nature of biomolecules and fluorofullerenes '' . Phys. Rev. Lett. 91 ( 9 ) : 090408 . arXiv : quant - ph / 0309016 . Bibcode : 2003PhRvL ... 91i0408H . doi : 10.1103 / PhysRevLett. 91.090408 . PMID 14525169 . Jump up ^ Clauser , John F. ; S. Li ( 1994 ) . `` Talbot von Lau interefometry with cold slow potassium atoms '' . Phys. Rev. A. 49 ( 4 ) : R2213 -- 17 . Bibcode : 1994PhRvA ... 49.2213 C . doi : 10.1103 / PhysRevA. 49. R2213 . PMID 9910609 . Jump up ^ Brezger , Björn ; Lucia Hackermüller ; Stefan Uttenthaler ; Julia Petschinka ; Markus Arndt ; Anton Zeilinger ( 2002 ) . `` Matter - wave interferometer for large molecules '' . Phys. Rev. Lett. 88 ( 10 ) : 100404 . arXiv : quant - ph / 0202158 . Bibcode : 2002PhRvL ... 88j0404B . doi : 10.1103 / PhysRevLett. 88.100404 . PMID 11909334 . Archived from the original on 2016 - 05 - 21 . Jump up ^ Hornberger , Klaus ; Stefan Uttenthaler ; Björn Brezger ; Lucia Hackermüller ; Markus Arndt ; Anton Zeilinger ( 2003 ) . `` Observation of Collisional Decoherence in Interferometry '' . Phys. Rev. Lett. 90 ( 16 ) : 160401 . arXiv : quant - ph / 0303093 . Bibcode : 2003PhRvL ... 90p0401H . doi : 10.1103 / PhysRevLett. 90.160401 . PMID 12731960 . Archived from the original on 2016 - 05 - 21 . Jump up ^ Hackermüller , Lucia ; Klaus Hornberger ; Björn Brezger ; Anton Zeilinger ; Markus Arndt ( 2004 ) . `` Decoherence of matter waves by thermal emission of radiation '' . Nature . 427 ( 6976 ) : 711 -- 714 . arXiv : quant - ph / 0402146 . Bibcode : 2004Natur. 427 ... 711H . doi : 10.1038 / nature02276 . PMID 14973478 . Jump up ^ Gerlich , Stefan ; et al. ( 2011 ) . `` Quantum interference of large organic molecules '' . Nature Communications . 2 ( 263 ) . Bibcode : 2011NatCo ... 2E. 263G . doi : 10.1038 / ncomms1263 . PMC 3104521 . PMID 21468015 . Jump up ^ Eibenberger , S. ; Gerlich , S. ; Arndt , M. ; Mayor , M. ; Tüxen , J. ( 2013 ) . `` Matter -- wave interference of particles selected from a molecular library with masses exceeding 10 000 amu '' . Physical Chemistry Chemical Physics. 15 ( 35 ) : 14696 -- 14700 . arXiv : 1310.8343 . Bibcode : 2013PCCP ... 1514696E . doi : 10.1039 / c3cp51500a . PMID 23900710 . Jump up ^ Peter Gabriel Bergmann , The Riddle of Gravitation , Courier Dover Publications , 1993 ISBN 0 - 486 - 27378 - 4 online Jump up ^ https://www.youtube.com/watch?v=W9yWv5dqSKk - You Tube video - Yves Couder Explains Wave / Particle Duality via Silicon Droplets Jump up ^ Y . Couder , E. Fort , Single - Particle Diffraction and Interference at a Macroscopic Scale , PRL 97 , 154101 ( 2006 ) online Jump up ^ A. Eddi , E. Fort , F. Moisy , Y . Couder , Unpredictable Tunneling of a Classical Wave -- Particle Association , PRL 102 , 240401 ( 2009 ) Jump up ^ Fort , E. ; Eddi , A. ; Boudaoud , A. ; Moukhtar , J. ; Couder , Y. ( 2010 ) . `` Path - memory induced quantization of classical orbits '' . PNAS. 107 ( 41 ) : 17515 -- 17520 . arXiv : 1307.6051 . Bibcode : 2010PNAS ... 10717515F . doi : 10.1073 / pnas. 1007386107 . Jump up ^ http://prl.aps.org/abstract/PRL/v108/i26/e264503 - Level Splitting at Macroscopic Scale Jump up ^ ( Buchanan pp. 29 -- 31 ) Jump up ^ Afshar , S.S. ; et al. ( 2007 ) . `` Paradox in Wave Particle Duality '' . Found . Phys. 37 : 295 . arXiv : quant - ph / 0702188 . Bibcode : 2007FoPh ... 37 ... 295A . doi : 10.1007 / s10701 - 006 - 9102 - 8 . CS1 maint : Explicit use of et al. ( link ) Jump up ^ Kastner , R ( 2005 ) . `` Why the Afshar experiment does not refute complementarity '' . Studies in History and Philosophy of Science Part B : Studies in History and Philosophy of Modern Physics. 36 ( 4 ) : 649 -- 658 . arXiv : quant - ph / 0502021 . Bibcode : 2005SHPMP ... 36 ... 649K . doi : 10.1016 / j. shpsb. 2005.04. 006 -- via Elsevier Science Direct . Jump up ^ Steuernagel , Ole ( 2007 - 08 - 03 ) . `` Afshar 's Experiment Does Not Show a Violation of Complementarity '' . Foundations of Physics. 37 ( 9 ) : 1370 -- 1385 . arXiv : quant - ph / 0512123 . Bibcode : 2007FoPh ... 37.1370 S . doi : 10.1007 / s10701 - 007 - 9153 - 5 . ISSN 0015 - 9018 . Jump up ^ Jacques , V. ; Lai , N.D. ; Dréau , A. ; Zheng , D. ; Chauvat , D. ; Treussart , F. ; Grangier , P. ; Roch , J. - F. ( 2008 - 01 - 01 ) . `` Illustration of quantum complementarity using single photons interfering on a grating '' . New Journal of Physics. 10 ( 12 ) : 123009 . arXiv : 0807.5079 . Bibcode : 2008NJPh ... 10l3009J . doi : 10.1088 / 1367 - 2630 / 10 / 12 / 123009 . ISSN 1367 - 2630 . Jump up ^ Georgiev , Danko ( 2012 - 01 - 26 ) . `` Quantum Histories and Quantum Complementarity '' . ISRN Mathematical Physics. 2012 : 1 -- 37 . doi : 10.5402 / 2012 / 327278 . Jump up ^ David Haddon . `` Recovering Rational Science '' . Touchstone . Retrieved 2007 - 09 - 12 . Jump up ^ Paul Arthur Schilpp , ed , Albert Einstein : Philosopher - Scientist , Open Court ( 1949 ) , ISBN 0 - 87548 - 133 - 7 , p 51 . Jump up ^ See section VI ( e ) of Everett 's thesis : The Theory of the Universal Wave Function , in Bryce Seligman DeWitt , R. Neill Graham , eds , The Many - Worlds Interpretation of Quantum Mechanics , Princeton Series in Physics , Princeton University Press ( 1973 ) , ISBN 0 - 691 - 08131 - X , pp 3 -- 140 . Jump up ^ Horodecki , R. ( 1981 ) . `` De broglie wave and its dual wave '' . Phys . Lett . A. 87 ( 3 ) : 95 -- 97 . Bibcode : 1981PhLA ... 87 ... 95H . doi : 10.1016 / 0375 - 9601 ( 81 ) 90571 - 5 . Jump up ^ Horodecki , R. ( 1983 ) . `` Superluminal singular dual wave '' . Lett . Novo Cimento. 38 : 509 -- 511 . Jump up ^ Duane , W. ( 1923 ) . The transfer in quanta of radiation momentum to matter , Proc. Natl. Acad. Sci. 9 ( 5 ) : 158 -- 164 . Jump up ^ Landé , A. ( 1951 ) . Quantum Mechanics , Sir Isaac Pitman and Sons , London , pp. 19 -- 22 . Jump up ^ Heisenberg , W. ( 1930 ) . The Physical Principles of the Quantum Theory , translated by C. Eckart and F.C. Hoyt , University of Chicago Press , Chicago , pp. 77 -- 78 . Jump up ^ Eddington , Arthur Stanley ( 1928 ) . The Nature of the Physical World . Cambridge , UK. : MacMillan . p. 201 . Jump up ^ Penrose , Roger ( 2007 ) . The Road to Reality : A Complete Guide to the Laws of the Universe . Vintage . p. 521 , § 21.10 . ISBN 978 - 0 - 679 - 77631 - 4 . Jump up ^ http://www.quantum-relativity.org/Quantum-Relativity.pdf . See Q. Zheng and T. Kobayashi , Quantum Optics as a Relativistic Theory of Light ; Physics Essays 9 ( 1996 ) 447 . Annual Report , Department of Physics , School of Science , University of Tokyo ( 1992 ) 240 . Jump up ^ `` Press release : The first ever photograph of light as both a particle and wave '' . Ecole Polytechnique Federale de Lausanne. 2 March 2015 . External links ( edit ) Animation , applications and research linked to the wave - particle duality and other basic quantum phenomena ( Université Paris Sud ) H. Nikolic . `` Quantum mechanics : Myths and facts '' . Foundations of Physics. 37 : 1563 -- 1611 . arXiv : quant - ph / 0609163 . Bibcode : 2007FoPh ... 37.1563 N . doi : 10.1007 / s10701 - 007 - 9176 - y . Young & Geller . `` College Physics '' . B. Crowell . `` Ch. 34 , Light as a Particle '' ( Web page ) . Retrieved December 10 , 2006 . E.H. Carlson , Wave -- Particle Duality : Light on Project PHYSNET R. Nave . `` Wave -- Particle Duality '' ( Web page ) . HyperPhysics . Georgia State University , Department of Physics and Astronomy . Retrieved December 12 , 2005 . Juffmann , Thomas ; et al. ( 25 March 2012 ) . `` Real - time single - molecule imaging of quantum interference '' . Nature Nanotechnology . Retrieved 21 January 2014 . 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Question: who proposed that electrons behave like waves and particles

Max Planck, Albert Einstein, Louis de Broglie, Arthur Compton, Niels Bohr and many others


Current members of the United States Senate - wikipedia Current members of the United States Senate Jump to : navigation , search The United States Senate party membership by state . States with two Democratic U.S. Senators are in blue , states with two Republican U.S. Senators are in red , and those with one of each are in purple . States with an independent U.S. Senator are marked with green stripes on a blue or red background , depending on the party of the other U.S. Senator . The United States Senate consists of 100 members , two from each of the 50 states . Below is a list of the current U.S. Senators , sitting in the 115th United States Congress . Affiliation Members Republican Party 51 Democratic Party 47 Independent Total 100 Contents ( hide ) 1 Leadership 1.1 Majority ( Republican ) leadership 1.2 Minority ( Democratic ) leadership 2 Senators 3 See also 4 Notes 5 References Leadership ( edit ) Office Party Officer State Since President of the Senate Republican Mike Pence Indiana January 20 , 2017 President pro tempore Republican Orrin Hatch Utah January 3 , 2015 Party Dean since January 3 , 2013 Majority ( Republican ) leadership ( edit ) Office Officer State Since Senate Majority Leader Mitch McConnell Kentucky January 3 , 2015 Party Leader since January 3 , 2007 Senate Majority Whip John Cornyn Texas January 3 , 2015 Party Whip since January 3 , 2013 Chair , Republican Conference John Thune South Dakota January 26 , 2012 Chair , Senate Republican Policy Committee John Barrasso Wyoming January 3 , 2013 Vice Chair , Republican Conference Roy Blunt Missouri January 3 , 2013 Chair , National Republican Senatorial Committee Cory Gardner Colorado January 3 , 2017 Chair , Senate Republican Steering Committee Mike Lee Utah January 3 , 2015 Senate Republican Chief Deputy Whip Mike Crapo Idaho January 3 , 2013 Minority ( Democratic ) leadership ( edit ) Office Officer State Since Senate Minority Leader Chair , Democratic Caucus Chuck Schumer New York January 3 , 2017 Party Leader since January 3 , 2017 Senate Minority Whip Dick Durbin Illinois January 3 , 2015 Party Whip since January 3 , 2005 Senate Assistant Democratic Leader Patty Murray Washington January 3 , 2017 Chair , Senate Democratic Policy Committee Debbie Stabenow Michigan January 3 , 2017 Vice Chair , Democratic Caucus Mark Warner Virginia January 3 , 2017 Elizabeth Warren Massachusetts January 3 , 2017 Chair , Senate Democratic Steering Committee Amy Klobuchar Minnesota January 3 , 2017 Chair , Senate Democratic Outreach Committee Bernie Sanders Vermont January 3 , 2017 Vice Chair , Senate Democratic Policy Committee Joe Manchin West Virginia January 3 , 2017 Secretary , Democratic Caucus Tammy Baldwin Wisconsin January 3 , 2017 Chair , Democratic Senatorial Campaign Committee Chris Van Hollen Maryland January 3 , 2017 Senate Democratic Chief Deputy Whip Jeff Merkley Oregon January 3 , 2017 President pro tempore emeritus Patrick Leahy Vermont January 3 , 2015 Party Dean since December 17 , 2012 Senators ( edit ) The relevance of particular information in ( or previously in ) this article or section is disputed . 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( November 2017 ) Legend Democratic Republican Independent State Portrait Name Previous experience Assumed office Seat up Alabama Shelby , Richard Richard Shelby ( 1934 - 05 - 06 ) May 6 , 1934 ( age 83 ) Alabama Senate , U.S. House January 3 , 1987 ( 31 years ago ) ( 1987 - 01 - 03 ) 2022 Jones , Doug Doug Jones ( 1954 - 05 - 04 ) May 4 , 1954 ( age 63 ) U.S. Attorney January 3 , 2018 ( 22 days ago ) ( 2018 - 01 - 03 ) 2020 Alaska Murkowski , Lisa Lisa Murkowski ( 1957 - 05 - 22 ) May 22 , 1957 ( age 60 ) Alaska Senate December 20 , 2002 ( 15 years ago ) ( 2002 - 12 - 20 ) 2022 Sullivan , Dan Dan Sullivan ( 1964 - 11 - 13 ) November 13 , 1964 ( age 53 ) Alaska Attorney General , U.S. Assistant Secretary of State January 3 , 2015 ( 3 years ago ) ( 2015 - 01 - 03 ) 2020 Arizona McCain , John John McCain ( 1936 - 08 - 29 ) August 29 , 1936 ( age 81 ) U.S. House January 3 , 1987 ( 31 years ago ) ( 1987 - 01 - 03 ) 2022 Flake , Jeff Jeff Flake ( 1962 - 12 - 31 ) December 31 , 1962 ( age 55 ) U.S. House January 3 , 2013 ( 5 years ago ) ( 2013 - 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01 - 03 ) 2022 Georgia Isakson , Johnny Johnny Isakson ( 1944 - 12 - 28 ) December 28 , 1944 ( age 73 ) U.S. House , Georgia House & Senate January 3 , 2005 ( 13 years ago ) ( 2005 - 01 - 03 ) 2022 Perdue , David David Perdue ( 1949 - 12 - 10 ) December 10 , 1949 ( age 68 ) Chief Executive Officer January 3 , 2015 ( 3 years ago ) ( 2015 - 01 - 03 ) 2020 Hawaii Schatz , Brian Brian Schatz ( 1972 - 10 - 20 ) October 20 , 1972 ( age 45 ) Lieutenant Governor of Hawaii , Hawaii House December 26 , 2012 ( 5 years ago ) ( 2012 - 12 - 26 ) 2022 Hirono , Mazie Mazie Hirono ( 1947 - 11 - 03 ) November 3 , 1947 ( age 70 ) U.S. House , Hawaii House , Lieutenant Governor of Hawaii January 3 , 2013 ( 5 years ago ) ( 2013 - 01 - 03 ) 2018 Idaho Crapo , Mike Mike Crapo ( 1951 - 05 - 20 ) May 20 , 1951 ( age 66 ) U.S. House , Idaho Senate January 3 , 1999 ( 19 years ago ) ( 1999 - 01 - 03 ) 2022 Risch , Jim Jim Risch ( 1943 - 05 - 03 ) May 3 , 1943 ( age 74 ) Governor & Lieutenant Governor of Idaho , Idaho Senate President pro tempore January 3 , 2009 ( 9 years ago ) ( 2009 - 01 - 03 ) 2020 Illinois Durbin , Dick Dick Durbin ( 1944 - 11 - 21 ) November 21 , 1944 ( age 73 ) U.S. House January 3 , 1997 ( 21 years ago ) ( 1997 - 01 - 03 ) 2020 Duckworth , Tammy Tammy Duckworth ( 1968 - 03 - 12 ) March 12 , 1968 ( age 49 ) U.S. House , U.S. Assistant Secretary of Veterans Affairs , Illinois Director of Veterans Affairs January 3 , 2017 ( 12 months ago ) ( 2017 - 01 - 03 ) 2022 Indiana Donnelly , Joe Joe Donnelly ( 1955 - 09 - 29 ) September 29 , 1955 ( age 62 ) U.S. House January 3 , 2013 ( 5 years ago ) ( 2013 - 01 - 03 ) 2018 Young , Todd Todd Young ( 1972 - 08 - 24 ) August 24 , 1972 ( age 45 ) U.S. House January 3 , 2017 ( 12 months ago ) ( 2017 - 01 - 03 ) 2022 Iowa Grassley , Chuck Chuck Grassley ( 1933 - 09 - 17 ) September 17 , 1933 ( age 84 ) U.S. House , Iowa House January 3 , 1981 ( 37 years ago ) ( 1981 - 01 - 03 ) 2022 Ernst , Joni Joni Ernst ( 1970 - 07 - 01 ) July 1 , 1970 ( age 47 ) Iowa Senate January 3 , 2015 ( 3 years ago ) ( 2015 - 01 - 03 ) 2020 Kansas Roberts , Pat Pat Roberts ( 1936 - 04 - 20 ) April 20 , 1936 ( age 81 ) U.S. House January 3 , 1997 ( 21 years ago ) ( 1997 - 01 - 03 ) 2020 Moran , Jerry Jerry Moran ( 1954 - 05 - 29 ) May 29 , 1954 ( age 63 ) U.S. House , Kansas Senate January 3 , 2011 ( 7 years ago ) ( 2011 - 01 - 03 ) 2022 Kentucky McConnell , Mitch Mitch McConnell ( 1942 - 02 - 20 ) February 20 , 1942 ( age 75 ) U.S. Deputy Assistant Attorney General for Legislative Affairs Judge - Executive of Jefferson County January 3 , 1985 ( 33 years ago ) ( 1985 - 01 - 03 ) 2020 Paul , Rand Rand Paul ( 1963 - 01 - 07 ) January 7 , 1963 ( age 55 ) Physician , congressional intern January 3 , 2011 ( 7 years ago ) ( 2011 - 01 - 03 ) 2022 Louisiana Cassidy , Bill Bill Cassidy ( 1957 - 09 - 28 ) September 28 , 1957 ( age 60 ) U.S. House , Louisiana Senate January 3 , 2015 ( 3 years ago ) ( 2015 - 01 - 03 ) 2020 Kennedy , John John Kennedy ( 1951 - 11 - 21 ) November 21 , 1951 ( age 66 ) Louisiana Treasurer January 3 , 2017 ( 12 months ago ) ( 2017 - 01 - 03 ) 2022 Maine Collins , Susan Susan Collins ( 1952 - 12 - 07 ) December 7 , 1952 ( age 65 ) Maine Professional and Financial Regulation Commissioner January 3 , 1997 ( 21 years ago ) ( 1997 - 01 - 03 ) 2020 King , Angus Angus King ( 1944 - 03 - 31 ) March 31 , 1944 ( age 73 ) Maine Governor January 3 , 2013 ( 5 years ago ) ( 2013 - 01 - 03 ) 2018 Maryland Cardin , Ben Ben Cardin ( 1943 - 10 - 05 ) October 5 , 1943 ( age 74 ) U.S. House , Speaker of the Maryland House January 3 , 2007 ( 11 years ago ) ( 2007 - 01 - 03 ) 2018 Van Hollen , Chris Chris Van Hollen ( 1959 - 01 - 10 ) January 10 , 1959 ( age 59 ) U.S. House , Maryland General Assembly January 3 , 2017 ( 12 months ago ) ( 2017 - 01 - 03 ) 2022 Massachusetts Warren , Elizabeth Elizabeth Warren ( 1949 - 06 - 22 ) June 22 , 1949 ( age 68 ) COP Chair , CFPB Special Advisor , law professor January 3 , 2013 ( 5 years ago ) ( 2013 - 01 - 03 ) 2018 Markey , Ed Ed Markey ( 1946 - 07 - 11 ) July 11 , 1946 ( age 71 ) U.S. House , Massachusetts House July 16 , 2013 ( 4 years ago ) ( 2013 - 07 - 16 ) 2020 Michigan Stabenow , Debbie Debbie Stabenow ( 1950 - 04 - 29 ) April 29 , 1950 ( age 67 ) U.S. House , Michigan House & Senate January 3 , 2001 ( 17 years ago ) ( 2001 - 01 - 03 ) 2018 Peters , Gary Gary Peters ( 1958 - 12 - 01 ) December 1 , 1958 ( age 59 ) U.S. House , Michigan Senate January 3 , 2015 ( 3 years ago ) ( 2015 - 01 - 03 ) 2020 Minnesota Klobuchar , Amy Amy Klobuchar ( 1960 - 05 - 25 ) May 25 , 1960 ( age 57 ) Hennepin County Attorney January 3 , 2007 ( 11 years ago ) ( 2007 - 01 - 03 ) 2018 Smith , Tina Tina Smith ( 1958 - 03 - 04 ) March 4 , 1958 ( age 59 ) Minnesota Lieutenant Governor January 3 , 2018 ( 22 days ago ) ( 2018 - 01 - 03 ) 2018 Mississippi Cochran , Thad Thad Cochran ( 1937 - 12 - 07 ) December 7 , 1937 ( age 80 ) U.S. House December 27 , 1978 ( 39 years ago ) ( 1978 - 12 - 27 ) 2020 Wicker , Roger Roger Wicker ( 1951 - 07 - 05 ) July 5 , 1951 ( age 66 ) U.S. House , Mississippi Senate December 31 , 2007 ( 10 years ago ) ( 2007 - 12 - 31 ) 2018 Missouri McCaskill , Claire Claire McCaskill ( 1953 - 07 - 24 ) July 24 , 1953 ( age 64 ) Missouri Auditor , Missouri House January 3 , 2007 ( 11 years ago ) ( 2007 - 01 - 03 ) 2018 Blunt , Roy Roy Blunt ( 1950 - 01 - 10 ) January 10 , 1950 ( age 68 ) U.S. House , Missouri Secretary of State January 3 , 2011 ( 7 years ago ) ( 2011 - 01 - 03 ) 2022 Montana Tester , Jon Jon Tester ( 1956 - 08 - 21 ) August 21 , 1956 ( age 61 ) Montana Senate President January 3 , 2007 ( 11 years ago ) ( 2007 - 01 - 03 ) 2018 Daines , Steve Steve Daines ( 1962 - 08 - 20 ) August 20 , 1962 ( age 55 ) U.S. House January 3 , 2015 ( 3 years ago ) ( 2015 - 01 - 03 ) 2020 Nebraska Fischer , Deb Deb Fischer ( 1951 - 03 - 01 ) March 1 , 1951 ( age 66 ) Nebraska Legislature January 3 , 2013 ( 5 years ago ) ( 2013 - 01 - 03 ) 2018 Sasse , Ben Ben Sasse ( 1972 - 02 - 22 ) February 22 , 1972 ( age 45 ) Assistant Secretary for Planning and Evaluation ( HHS ) , Midland University President January 3 , 2015 ( 3 years ago ) ( 2015 - 01 - 03 ) 2020 Nevada Heller , Dean Dean Heller ( 1960 - 05 - 10 ) May 10 , 1960 ( age 57 ) U.S. House , Nevada Secretary of State , Nevada Assembly May 9 , 2011 ( 6 years ago ) ( 2011 - 05 - 09 ) 2018 Cortez Masto , Catherine Catherine Cortez Masto ( 1964 - 03 - 29 ) March 29 , 1964 ( age 53 ) Nevada Attorney General January 3 , 2017 ( 12 months ago ) ( 2017 - 01 - 03 ) 2022 New Hampshire Shaheen , Jeanne Jeanne Shaheen ( 1947 - 01 - 28 ) January 28 , 1947 ( age 70 ) New Hampshire Governor , New Hampshire Senate January 3 , 2009 ( 9 years ago ) ( 2009 - 01 - 03 ) 2020 Hassan , Maggie Maggie Hassan ( 1958 - 02 - 27 ) February 27 , 1958 ( age 59 ) New Hampshire Governor , New Hampshire Senate January 3 , 2017 ( 12 months ago ) ( 2017 - 01 - 03 ) 2022 New Jersey Menendez , Bob Bob Menendez ( 1954 - 01 - 01 ) January 1 , 1954 ( age 64 ) U.S. House , New Jersey General Assembly , New Jersey Senate January 18 , 2006 ( 12 years ago ) ( 2006 - 01 - 18 ) 2018 Booker , Cory Cory Booker ( 1969 - 04 - 27 ) April 27 , 1969 ( age 48 ) Newark Mayor October 31 , 2013 ( 4 years ago ) ( 2013 - 10 - 31 ) 2020 New Mexico Udall , Tom Tom Udall ( 1948 - 05 - 18 ) May 18 , 1948 ( age 69 ) U.S. House , New Mexico Attorney General , Assistant U.S. Attorney January 3 , 2009 ( 9 years ago ) ( 2009 - 01 - 03 ) 2020 Heinrich , Martin Martin Heinrich ( 1971 - 10 - 17 ) October 17 , 1971 ( age 46 ) U.S. House , Albuquerque City Council January 3 , 2013 ( 5 years ago ) ( 2013 - 01 - 03 ) 2018 New York Schumer , Chuck Chuck Schumer ( 1950 - 11 - 23 ) November 23 , 1950 ( age 67 ) U.S. House , New York Assembly January 3 , 1999 ( 19 years ago ) ( 1999 - 01 - 03 ) 2022 Gillibrand , Kirsten Kirsten Gillibrand ( 1966 - 12 - 09 ) December 9 , 1966 ( age 51 ) U.S. House , U.S. HUD special counsel January 26 , 2009 ( 8 years ago ) ( 2009 - 01 - 26 ) 2018 North Carolina Burr , Richard Richard Burr ( 1955 - 11 - 30 ) November 30 , 1955 ( age 62 ) U.S. House January 3 , 2005 ( 13 years ago ) ( 2005 - 01 - 03 ) 2022 Tillis , Thom Thom Tillis ( 1960 - 08 - 30 ) August 30 , 1960 ( age 57 ) North Carolina House Speaker January 3 , 2015 ( 3 years ago ) ( 2015 - 01 - 03 ) 2020 North Dakota Hoeven , John John Hoeven ( 1957 - 03 - 13 ) March 13 , 1957 ( age 60 ) North Dakota Governor January 3 , 2011 ( 7 years ago ) ( 2011 - 01 - 03 ) 2022 Heitkamp , Heidi Heidi Heitkamp ( 1955 - 10 - 30 ) October 30 , 1955 ( age 62 ) North Dakota Attorney General , Tax Commissioner January 3 , 2013 ( 5 years ago ) ( 2013 - 01 - 03 ) 2018 Ohio Brown , Sherrod Sherrod Brown ( 1952 - 11 - 09 ) November 9 , 1952 ( age 65 ) U.S. House , Ohio Secretary of State , Ohio House January 3 , 2007 ( 11 years ago ) ( 2007 - 01 - 03 ) 2018 Portman , Rob Rob Portman ( 1955 - 12 - 19 ) December 19 , 1955 ( age 62 ) U.S. House , U.S. Trade Representative , OMB Director January 3 , 2011 ( 7 years ago ) ( 2011 - 01 - 03 ) 2022 Oklahoma Inhofe , Jim Jim Inhofe ( 1934 - 11 - 17 ) November 17 , 1934 ( age 83 ) U.S. House , Tulsa Mayor , Oklahoma House & Senate November 17 , 1994 ( 23 years ago ) ( 1994 - 11 - 17 ) 2020 Lankford , James James Lankford ( 1968 - 03 - 04 ) March 4 , 1968 ( age 49 ) U.S. House January 3 , 2015 ( 3 years ago ) ( 2015 - 01 - 03 ) 2022 Oregon Wyden , Ron Ron Wyden ( 1949 - 05 - 03 ) May 3 , 1949 ( age 68 ) U.S. House February 6 , 1996 ( 21 years ago ) ( 1996 - 02 - 06 ) 2022 Merkley , Jeff Jeff Merkley ( 1956 - 10 - 24 ) October 24 , 1956 ( age 61 ) Oregon House Speaker , Defense Department , CBO analyst January 3 , 2009 ( 9 years ago ) ( 2009 - 01 - 03 ) 2020 Pennsylvania Casey Jr. , Bob Bob Casey Jr . ( 1960 - 04 - 13 ) April 13 , 1960 ( age 57 ) Pennsylvania Treasurer , Pennsylvania Auditor January 3 , 2007 ( 11 years ago ) ( 2007 - 01 - 03 ) 2018 Toomey , Pat Pat Toomey ( 1961 - 11 - 17 ) November 17 , 1961 ( age 56 ) U.S. House January 3 , 2011 ( 7 years ago ) ( 2011 - 01 - 03 ) 2022 Rhode Island Reed , Jack Jack Reed ( 1949 - 11 - 12 ) November 12 , 1949 ( age 68 ) U.S. House , Rhode Island Senate January 3 , 1997 ( 21 years ago ) ( 1997 - 01 - 03 ) 2020 Whitehouse , Sheldon Sheldon Whitehouse ( 1955 - 10 - 20 ) October 20 , 1955 ( age 62 ) West Virginia Supreme Court law clerk , Rhode Island Attorney General January 3 , 2007 ( 11 years ago ) ( 2007 - 01 - 03 ) 2018 South Carolina Graham , Lindsey Lindsey Graham ( 1955 - 07 - 09 ) July 9 , 1955 ( age 62 ) U.S. House , South Carolina House January 3 , 2003 ( 15 years ago ) ( 2003 - 01 - 03 ) 2020 Scott , Tim Tim Scott ( 1965 - 09 - 19 ) September 19 , 1965 ( age 52 ) U.S. House , South Carolina House , Charleston County Council January 2 , 2013 ( 5 years ago ) ( 2013 - 01 - 02 ) 2022 South Dakota Thune , John John Thune ( 1961 - 01 - 07 ) January 7 , 1961 ( age 57 ) U.S. House , Legislative aide , South Dakota Republican Party Executive Director January 3 , 2005 ( 13 years ago ) ( 2005 - 01 - 03 ) 2022 Rounds , Mike Mike Rounds ( 1954 - 10 - 24 ) October 24 , 1954 ( age 63 ) South Dakota Governor , South Dakota Senate January 3 , 2015 ( 3 years ago ) ( 2015 - 01 - 03 ) 2020 Tennessee Alexander , Lamar Lamar Alexander ( 1940 - 07 - 03 ) July 3 , 1940 ( age 77 ) Tennessee Governor , U.S. Secretary of Education January 3 , 2003 ( 15 years ago ) ( 2003 - 01 - 03 ) 2020 Corker , Bob Bob Corker ( 1952 - 08 - 24 ) August 24 , 1952 ( age 65 ) Chattanooga Mayor January 3 , 2007 ( 11 years ago ) ( 2007 - 01 - 03 ) 2018 Texas Cornyn , John John Cornyn ( 1952 - 02 - 02 ) February 2 , 1952 ( age 65 ) Texas Attorney General , Texas Supreme Court ( Associate Justice ) December 1 , 2002 ( 15 years ago ) ( 2002 - 12 - 01 ) 2020 Cruz , Ted Ted Cruz ( 1970 - 12 - 22 ) December 22 , 1970 ( age 47 ) SCOTUS law clerk , U.S. Assoc . Deputy AG , Texas Solicitor General January 3 , 2013 ( 5 years ago ) ( 2013 - 01 - 03 ) 2018 Utah Hatch , Orrin Orrin Hatch ( 1934 - 03 - 22 ) March 22 , 1934 ( age 83 ) Attorney January 3 , 1977 ( 41 years ago ) ( 1977 - 01 - 03 ) 2018 Lee , Mike Mike Lee ( 1971 - 06 - 04 ) June 4 , 1971 ( age 46 ) Assistant U.S. Attorney January 3 , 2011 ( 7 years ago ) ( 2011 - 01 - 03 ) 2022 Vermont Leahy , Patrick Patrick Leahy ( 1940 - 03 - 31 ) March 31 , 1940 ( age 77 ) Chittenden County State 's Attorney January 3 , 1975 ( 43 years ago ) ( 1975 - 01 - 03 ) 2022 Sanders , Bernie Bernie Sanders ( 1941 - 09 - 08 ) September 8 , 1941 ( age 76 ) Burlington Mayor , U.S. House January 3 , 2007 ( 11 years ago ) ( 2007 - 01 - 03 ) 2018 Virginia Warner , Mark Mark Warner ( 1954 - 12 - 15 ) December 15 , 1954 ( age 63 ) Virginia Governor , Virginia Democratic Party Chair January 3 , 2009 ( 9 years ago ) ( 2009 - 01 - 03 ) 2020 Kaine , Tim Tim Kaine ( 1958 - 02 - 26 ) February 26 , 1958 ( age 59 ) Virginia Governor , Lt. Governor , Democratic National Committee Chair , Mayor of Richmond , Virginia January 3 , 2013 ( 5 years ago ) ( 2013 - 01 - 03 ) 2018 Washington Murray , Patty Patty Murray ( 1950 - 10 - 11 ) October 11 , 1950 ( age 67 ) Washington Senate , Shoreline School Board January 3 , 1993 ( 25 years ago ) ( 1993 - 01 - 03 ) 2022 Cantwell , Maria Maria Cantwell ( 1958 - 10 - 13 ) October 13 , 1958 ( age 59 ) U.S. House , Washington House January 3 , 2001 ( 17 years ago ) ( 2001 - 01 - 03 ) 2018 West Virginia Manchin , Joe Joe Manchin ( 1947 - 08 - 24 ) August 24 , 1947 ( age 70 ) West Virginia Governor , West Virginia Secretary of State , West Virginia House & Senate November 15 , 2010 ( 7 years ago ) ( 2010 - 11 - 15 ) 2018 Capito , Shelley Moore Shelley Moore Capito ( 1953 - 11 - 26 ) November 26 , 1953 ( age 64 ) U.S. House West Virginia House January 3 , 2015 ( 3 years ago ) ( 2015 - 01 - 03 ) 2020 Wisconsin Johnson , Ron Ron Johnson ( 1955 - 04 - 08 ) April 8 , 1955 ( age 62 ) Chief Executive Officer January 3 , 2011 ( 7 years ago ) ( 2011 - 01 - 03 ) 2022 Baldwin , Tammy Tammy Baldwin ( 1962 - 02 - 11 ) February 11 , 1962 ( age 55 ) U.S. House , Wisconsin Assembly January 3 , 2013 ( 5 years ago ) ( 2013 - 01 - 03 ) 2018 Wyoming Enzi , Mike Mike Enzi ( 1944 - 02 - 01 ) February 1 , 1944 ( age 73 ) Wyoming House & Senate January 3 , 1997 ( 21 years ago ) ( 1997 - 01 - 03 ) 2020 Barrasso , John John Barrasso ( 1952 - 07 - 21 ) July 21 , 1952 ( age 65 ) Wyoming Senate June 25 , 2007 ( 10 years ago ) ( 2007 - 06 - 25 ) 2018 See also ( edit ) Seniority in the United States Senate List of members of the United States Congress by longevity of service Notes ( edit ) Jump up ^ Senators Angus King of Maine and Bernie Sanders of Vermont caucus with the Democratic Party . Jump up ^ The Vice President of the United States is the President of the Senate Jump up ^ As Vice President , Pence represents no state , but his home state is Indiana . Jump up ^ Democrat Doug Jones was elected to succeed Luther Strange on December 12 , 2017 . Jones will be up for re-election in 2020 . Jump up ^ Appointed to the seat after Al Franken 's resignation . References ( edit ) Jump up ^ `` Jones victorious in stunning Alabama Senate upset '' . AP News . Retrieved 2017 - 12 - 13 . Jump up ^ `` Franken to make announcement Thursday as chorus grows for his resignation '' . ABC7 Chicago . 2017 - 12 - 06 . Retrieved 2017 - 12 - 09 . 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Question: how many senators are there in the us senate


Deposition ( phase transition ) - wikipedia Deposition ( phase transition ) Jump to : navigation , search This article includes a list of references , related reading or external links , but its sources remain unclear because it lacks inline citations . Please help to improve this article by introducing more precise citations. ( April 2011 ) ( Learn how and when to remove this template message ) Water vapor from humid winter - air deposits directly into a solid , crystalline frost pattern on a window , without ever being liquid in the process . Deposition is a thermodynamic process , a phase transition in which gas transforms into solid without passing through the liquid phase . The reverse of deposition is sublimation and hence sometimes deposition is called desublimation . One example of deposition is the process by which , in sub-freezing air , water vapor changes directly to ice without first becoming a liquid . This is how snow forms in clouds , as well as how frost and hoar frost form on the ground or other surfaces . Another example is when frost forms on a leaf . For deposition to occur , thermal energy must be removed from a gas . When the air becomes cold enough , water vapor in the air surrounding the leaf loses enough thermal energy to change into a solid . Even though the air temperature may be below the dew point , the water vapor may not be able to condense spontaneously if there is no way to remove the latent heat . When the leaf is introduced , the supercooled water vapor immediately begins to condense , but by this point is already past the freezing point . This causes the water vapor to change directly into a solid . Another example is the soot that is deposited on the walls of chimneys . Soot molecules rise from the fire in a hot and gaseous state . When they come into contact with the walls they cool , and change to the solid state , without formation of the liquid state . The process is made use of industrially in combustion chemical vapor deposition . There is an industrial coatings process , known as evaporative deposition , whereby a solid material is heated to the gaseous state in a low - pressure chamber , the gas molecules travel across the chamber space and then condense to the solid state on a target surface , forming a smooth and thin layer on the target surface . Again , the molecules do not go through an intermediate liquid state when going from the gas to the solid . See also physical vapor deposition , which is a class of processes used to deposit thin films of various materials onto various surfaces . Deposition releases energy and is an exothermic phase change . See also ( edit ) Phase transitions of matter To Solid Liquid Gas From Solid -- Melting Sublimation Liquid Freezing -- Evaporation Gas Deposition Condensation -- , References ( edit ) Jacobson , Mark Z. , Fundamentals of Atmospheric Modeling , Cambridge University Press , 2nd ed. , 2005 , p. 525 ISBN 978 - 0 - 521 - 83970 - 9 Moore , John W. , et al. , Principles of Chemistry : The Molecular Science , Brooks Cole , 2009 , p. 387 ISBN 978 - 0 - 495 - 39079 - 4 Whitten , Kenneth W. , et al. , Chemistry , Brooks - Cole , 9th ed. , 2009 , p. 7 ISBN 978 - 0 - 495 - 39163 - 0 Glencoe Science `` Focus on Physical Science '' States of matter ( list ) State Baryonic matter Solid Liquid Gas / Vapor Plasma Low energy Bose -- Einstein condensate Fermionic condensate Degenerate matter Quantum Hall Rydberg matter Rydberg polaron Strange matter Superfluid Supersolid Photonic matter High energy QCD matter Lattice QCD Quark -- gluon plasma Color - glass condensate Supercritical fluid Other states Colloid Glass Crystal Liquid crystal Time crystal Quantum spin liquid Exotic matter Programmable matter Dark matter Antimatter Magnetically ordered Antiferromagnet Ferrimagnet Ferromagnet String - net liquid Superglass Transitions Boiling Boiling point Condensation Critical line Critical point Crystallization Deposition Evaporation Flash evaporation Freezing Chemical ionization Ionization Lambda point Melting Melting point Recombination Regelation Saturated fluid Sublimation Supercooling Triple point Vaporization Vitrification Quantities Enthalpy of fusion Enthalpy of sublimation Enthalpy of vaporization Latent heat Latent internal energy Trouton 's ratio Volatility Concepts Binodal Compressed fluid Cooling curve Equation of state Leidenfrost effect Macroscopic quantum phenomena Mpemba effect Order and disorder ( physics ) Spinodal Superconductivity Superheated vapor Superheating Thermo - dielectric effect Retrieved from `` https://en.wikipedia.org/w/index.php?title=Deposition_(phase_transition)&oldid=832599453 '' Categories : Phase transitions Hidden categories : Articles lacking in - text citations from April 2011 All articles lacking in - text citations Talk About Wikipedia Català Dansk Deutsch Ελληνικά Español فارسی हिन्दी Interlingua Italiano עברית Nederlands 日本 語 Нохчийн Norsk Norsk nynorsk Polski Русский Slovenčina Suomi Svenska Türkçe Українська 中文 14 more Edit links This page was last edited on 26 March 2018 , at 23 : 06 . 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Question: phase change from gas to solid is called