Name: measuring light with wavelength and frequency
Uploaded: 2020-09-03T13:38:27.000Z
Duration: 2 min 12 s
Channel: JoVE

K12 Standards

Texas Essential Knowledge and Skills

High School

Chemistry and Physics

IPC.7

IPC.7.E

The Wave Nature of Light

La luz del sol, las microondas utilizadas para cocinar la comida y las ondas de radio emitidas por enrutadores wi-fi son todos ejemplos de radiación electromagnética. La radiación electromagnética es la transmisión de la energía que proviene del movimiento de las partículas cargadas eléctricamente. Este movimiento crea campos eléctricos y magnéticos que oscilan perpendicularmente y se propagan por el espacio en forma de ondas.Como todas las ondas, las ondas electromagnéticas se caracterizan por su amplitud, longitud de onda y frecuencia. La amplitud máxima es la distancia desde la línea media hasta el pico o valle de una ola. Determina la intensidad de la ola.Por ejemplo, la amplitud de la luz visible está relacionado con su brillo;cuanto mayor sea la amplitud, más brillante o más intensa sea la luz. La longitud de onda es la distancia entre puntos idénticos en ondas adyacentes, como picos o valles sucesivos;está simbolizado por la letra griega lambda. La radiación electromagnética se puede clasificar por longitud de onda, que puede variar desde kilómetros hasta picómetros.Por ejemplo, el rango de longitud de onda de la luz visible es de unos 400 a 750 nanómetros, que corresponden a la luz violeta y roja, respectivamente. La frecuencia, que está simbolizada por la letra griega nu, es el número de ciclos de onda que pasa por un punto de referencia en un segundo y se mide en hercios o ciclos por segundo. La longitud de onda es el ancho de un ciclo.La velocidad de una onda es el producto de su frecuencia y la longitud de onda. Por lo tanto, la frecuencia de una onda es directamente proporcional a la velocidad en la que viaja la ola. Sin embargo, es inversamente proporcional a la longitud de onda de la ola.Por lo tanto, las ondas con longitudes de onda largas, como las ondas de radio, tienen bajas frecuencias. Estas ondas son menos energéticas que las ondas con altas frecuencias y longitudes de onda cortas, como los rayos gamma.

la naturaleza ondulante de la luz

La naturaleza de la luz ha sido objeto de investigación desde la antigüedad. En el siglo XVII, Isaac Newton realizó experimentos con lentes y prismas y fue capaz de demostrar que la luz blanca consiste en la combinación de los colores individuales del arco iris. Newton explicó sus hallazgos ópticos en términos de una visión corpuscular de la luz, en la que la luz estaba compuesta de corrientes de partículas extremadamente diminutas que viajaban a altas velocidades de acuerdo con las leyes del movimiento de Newton. 
 
 Otros en el siglo XVII, como Christiaan Huygens, habían demostrado que fenómenos ópticos como la reflexión y la refracción podían ser igualmente bien explicados en términos de la luz como ondas que viajaban a alta velocidad a través de un medio llamado “éter luminiscente” que se pensaba que permeaba todo el espacio. A principios del siglo XIX, Thomas Young demostró que la luz que pasaba a través de rendijas estrechas y poco espaciadas, producía patrones de interferencia que no podían explicarse en términos de partículas newtonianas, sino que podían explicarse fácilmente en términos de ondas. Más tarde, en el siglo XIX, después de que James Clerk Maxwell desarrollara su teoría de la radiación electromagnética y mostrara que la luz era la parte visible de un amplio espectro de ondas electromagnéticas, la visión de la luz como partículas fue completamente desacreditada. 
 
 A finales del siglo XIX, los científicos veían el universo físico como apenas comprendido por dos dominios separados: La materia compuesta de partículas que se movían de acuerdo con las leyes del movimiento de Newton, y la radiación electromagnética consistente en ondas gobernadas por las ecuaciones de Maxwell. Hoy en día, estos dominios se conocen como mecánica clásica y electrodinámica clásica (o electromagnetismo clásico). Aunque había algunos fenómenos físicos que no podían explicarse dentro de este marco, los científicos en ese momento estaban tan seguros de la solidez general de este marco de referencia que consideraban estas aberraciones como paradojas desconcertantes que, en última instancia, se resolverían de alguna manera dentro de este marco de referencia. Estas paradojas condujeron a un marco de referencia contemporáneo que conecta íntimamente partículas y ondas a un nivel fundamental llamado dualidad onda-partícula, que ha reemplazado la visión clásica.
 
 La luz visible y otras formas de radiación electromagnética juegan papeles importantes en la química ya que pueden ser usadas para inferir las energías de los electrones dentro de los átomos y moléculas. Gran parte de la tecnología moderna se basa en la radiación electromagnética. Por ejemplo, las ondas de radio de un teléfono móvil, los rayos X utilizados por los dentistas, la energía utilizada para cocinar alimentos en el microondas, el calor radiante de los objetos al rojo vivo y la luz de la pantalla de su televisión son formas de radiación electromagnética, todas las cuales exhiben un comportamiento ondulante.
 
 <h4>Ondas</h4>
 
 Una onda es una oscilación o movimiento periódico que puede transportar energía de un punto en el espacio a otro. Podemos encontrar ejemplos comunes de ondas a nuestro alrededor. Sacudir el extremo de una cuerda transfiere energía de su mano al otro extremo de la cuerda, dejar caer una piedra en un estanque hace que las ondas se muevan hacia afuera a lo largo de la superficie del agua, y la expansión del aire que acompaña a un rayo genera ondas sonoras (trueno) que pueden viajar por varias millas. En cada uno de estos casos, la energía cinética se transfiere a través de la materia (la cuerda, el agua o el aire) mientras que la materia permanece esencialmente en su lugar.  
 
 Las ondas necesitan no ser restringidas para viajar a través de la materia. Como Maxwell lo demostró, las ondas electromagnéticas consisten en un campo eléctrico que oscila al paso de un campo magnético perpendicular, ambos perpendiculares a la dirección del recorrido. Estas ondas pueden viajar a través del vacío a una velocidad constante de 2,998 × 108 m/s, la velocidad de la luz (indicada por c).
 
 Todas las ondas, incluidas las formas de radiación electromagnética, se caracterizan por una longitud de onda (denotada por λ, la letra griega minúscula lambda), una frecuencia (denotada por ν, la letra griega minúscula nu) y una amplitud. 
 
 La longitud de onda es la distancia entre dos picos o valles consecutivos en una onda (medida en metros en el sistema SI). Las ondas electromagnéticas tienen longitudes de onda que caen dentro de un enorme rango, se han observado longitudes de onda de kilómetros (103 m) a los picómetros (10−12 m). La frecuencia es el número de ciclos de onda que pasan un punto especifico en el espacio en una cantidad de tiempo especifica (en el sistema SI, esto se mide en segundos). Un ciclo corresponde a una longitud de onda completa. La unidad de frecuencia, expresada como ciclos por segundo [s−1], es el hertz (Hz). Los múltiplos comunes de esta unidad son los megahertz (1 MHz = 1 × 106 Hz) y los gigahertz (1 GHz = 1 × 109 Hz). 
 
 La amplitud corresponde a la magnitud del desplazamiento de la onda y esto corresponde a la mitad de la altura entre los picos y los valles. La amplitud está relacionada con la intensidad de la onda, que para la luz es el brillo y para el sonido es el volumen. El producto de la longitud de onda de una onda (λ) y su frecuencia (ν), λν, es la velocidad de la onda. Por lo tanto, para la radiación electromagnética en el vacío, la velocidad es igual a la constante fundamental, c:
 
 <img alt="Eq1" src="https://www.jovecore.com/CDNSource/lessons/974/974_Equations-01.png" style="height: 40px;" />
 
 La longitud de onda y la frecuencia son inversamente proporcionales: A medida que aumenta la longitud de onda, la frecuencia disminuye. El espectro electromagnético es el rango de todos los tipos de radiación electromagnética. 
 
 Este texto ha sido adaptado de <a href="https://openstax.org/books/chemistry-2e/pages/6-1-electromagnetic-energy">Openstax, Química 2e, Sección 6,1: Energía electromagnética.</a>

La Naturaleza Ondulante de la Luz

La naturaleza de la luz ha sido objeto de investigación desde la antigüedad. En el siglo XVII, Isaac Newton realizó experimentos con lentes y prismas...

Education

Educación

JoVE Core

Chemistry

Química

Electronic Structure of Atoms

Estructura electrónica de los átomos

KEY TERMS AND CONCEPTS

TÉRMINOS Y CONCEPTOS CLAVE

measuring light with wavelength and frequency

Light can be described as an electromagnetic wave, and its behavior helps explain many patterns seen in science. For centuries, scientists have tried to understand light. Newton used lenses and prisms to show that white light is made of the colors of the rainbow mixed together. He explained light as tiny particles moving at high speed.

Other scientists, including Christiaan Huygens, showed that reflection and refraction could also be explained by treating light as a wave. At the time, people imagined these waves traveling through a medium called luminiferous aether, which was thought to fill all space. In the early 1800s, Thomas Young showed that light passing through two narrow slits makes an interference pattern. That result fit the wave model much better than the particle model.

James Clerk Maxwell later developed electromagnetic theory and showed that visible light is part of a much larger spectrum of electromagnetic waves. By the end of the nineteenth century, many scientists accepted a split view of the physical world. Matter was described as particles, while electromagnetic radiation was described as waves. These ideas are now called classical mechanics and classical electrodynamics, or classical electromagnetism.

Some experimental results did not fit that classical picture. Scientists first saw them as strange puzzles that might still be solved within the old framework. Those puzzles eventually led to wave-particle duality, a modern idea that links waves and particles at a basic level. This idea replaced the older view.

Electromagnetic radiation matters in chemistry because it can help reveal the energies of electrons in atoms and molecules. It also powers many technologies. Radio waves from a mobile phone, X-rays used by dentists, microwave energy used to cook food, radiant heat from red-hot objects, and the light from a television screen are all forms of electromagnetic radiation. Each of these shows wavelike behavior.

A wave is an oscillation, or repeating motion, that carries energy from one place to another. Rope waves, ripples on water after a pebble falls in, and sound waves from thunder are common examples. In these cases, energy moves through the rope, water, or air while the material itself stays mostly in place. Waves do not have to travel through matter, because electromagnetic waves can move through empty space.

Maxwell showed that electromagnetic waves contain an electric field and a magnetic field that oscillate together. These fields are perpendicular to each other and to the direction the wave travels. In a vacuum, electromagnetic waves move at 2.998 × 10^8 m/s, which is the speed of light, c. Like all waves, they are described by wavelength, frequency, and amplitude.

Wavelength is the distance between two peaks or two troughs. Frequency is the number of wave cycles that pass a point in a given time. Amplitude is the size of the wave’s displacement, which is half the height between a peak and a trough. Amplitude is related to intensity, so for light it affects brightness, and for sound it affects loudness. Wavelength and frequency are linked by the equation λν = speed, so in a vacuum c = λν. As wavelength increases, frequency decreases. Electromagnetic waves span a huge range, from kilometers to picometers, and the full set is called the electromagnetic spectrum.

Measuring Light with Wavelength and Frequency

measuring-light-with-wavelength-and-frequency

the wave nature of light

Light can be described as an electromagnetic wave, and its behavior helps explain many patterns seen in science. For centuries, scientists have tried to understand light. Newton used lenses and prisms to show that white light is made of the colors of the rainbow mixed together. He explained light as tiny particles moving at high speed. Other scientists, including Christiaan Huygens, showed that reflection and refraction could also be explained by treating light as a wave. At the time, people...

the electromagnetic spectrum

Electromagnetic Waves: Uses Across the Spectrum

The electromagnetic spectrum includes all electromagnetic radiation arranged by frequency and wavelength. Visible light is only a small part of it, and each color of visible light has its own frequency and wavelength. Different parts of the spectrum also use different units. Radio waves are usually measured in MHz, while the visible range is often measured in nm or angstroms. The spectrum is organized from radio waves to gamma rays as frequency increases and wavelength decreases. Radio waves...

interference and diffraction

Wave Patterns from Light and Slits

Light can form wave patterns through interference and diffraction. When two electromagnetic waves meet with their peaks and troughs lined up, they combine into a larger wave. This is constructive interference, and the waves are in phase. When a peak of one wave meets a trough of the other, the waves reduce each other. This is destructive interference, and the result has a much lower amplitude. Diffraction is another wave behavior. When light passes through a slit that is about the same size as...

photoelectric effect

Why Light Ejects Electrons from Metals

Light can eject electrons from a metal surface when it has the right frequency. This process is called the photoelectric effect. Each metal has its own threshold frequency, which is the minimum light frequency needed to free electrons. Light below the threshold frequency cannot cause emission, even if it is very bright. When the light frequency is above the threshold, electrons are ejected. In that case, the number of electrons released is directly proportional to the intensity, or brightness,...

the bohr model

Bohr’s Quantized Atomic Orbits

Bohr’s quantized atomic orbits explain why hydrogen atoms can stay stable. Early in the twentieth century, Ernest Rutherford and his colleagues described atoms as tiny dense nuclei with lighter electrons moving around them. This picture was called the planetary model because it compared the atom to a miniature solar system, with electrons orbiting the nucleus like planets around the sun. The simplest atom is hydrogen. It has one proton in the nucleus and one electron moving around it. In the...

emission spectra

Line Spectra from Heated Gases

Line spectra are produced when heated gases give off light at specific wavelengths. In contrast, hot solids, liquids, or condensed gases radiate excess energy as a continuous spectrum. That spectrum contains an unbroken range of wavelengths. A gas at low partial pressure can produce a line spectrum when it is excited by an electric current or heated. Fluorescent light bulbs and neon signs work in this way. Each element has its own characteristic set of lines, and molecules can also produce...

the de broglie wavelength

Electron Waves and Standing Orbits

Electron waves and standing orbits explain how tiny particles can behave like waves. Large objects in the macroscopic world, like a billiard ball on a table, follow classical physics. A ball keeps moving in a straight line unless it hits another ball or a force such as friction acts on it. It also has a well-defined position, velocity, and momentum, where momentum is mass times velocity. Waves behave differently from macroscopic particles. When waves interact, they can form interference...

the uncertainty principle

Electron Position and Momentum Limits

Heisenberg’s uncertainty principle sets a limit on how precisely we can know an electron’s position and momentum at the same time. Momentum is the motion of a particle, and the two measurements affect each other. If the momentum is known more accurately, the position becomes less certain, and the reverse is also true. Heisenberg described this limit with an equation that uses Planck’s constant. The equation shows the smallest possible uncertainty for position and momentum together. It explains...

the quantum-mechanical model of an atom

Electron Orbitals in Quantum Mechanics

Quantum mechanics explains how electrons behave in atoms using waves and probability. Erwin Schrödinger built on de Broglie’s idea that an electron in hydrogen could act like a circular standing wave instead of moving in fixed circular paths. He then derived the Schrödinger equation, which became a major step in modern atomic theory. When Schrödinger applied his equation to hydrogen-like atoms, it matched Bohr’s energy expression and the Rydberg formula for hydrogen spectra. He described...

quantum numbers

Electron Orbitals and Spin

Electron orbitals are described by quantum numbers that show where an electron is most likely to be found around the nucleus. These numbers come from the quantum mechanical model, which is based on solutions of the Schrödinger equation. They also help explain why electron energy comes in set values instead of changing smoothly. The principal quantum number, n, labels the energy level. It can be 1, 2, 3, and so on, and higher n values usually mean higher electron energy. This number also tells...

atomic orbitals

Electron Regions in Atomic Orbitals

Electron regions in atomic orbitals show where an electron is most likely to be found in an atom. These three-dimensional regions are often drawn as boundary surfaces around the densest part of the cloud. The shape of an orbital depends on the angular momentum quantum number, l. This value can range from 0 to n - 1, where n is the principal quantum number. For n = 1, only l = 0 is allowed. For n = 2, both l = 0 and l = 1 are allowed. Orbitals with the same value of l form a subshell. The l =...

the pauli exclusion principle

Electron Spin and Orbital Pairing

Electron spin and orbital pairing explain why only two electrons can fit in one atomic orbital. Electron configuration describes how electrons are arranged in an atom’s orbitals. It is written with three parts: the principal quantum number, n, the orbital type, or subshell, and a superscript that shows how many electrons are in that subshell. For example, 2p4 means four electrons in a p subshell with n = 2, and 3d8 means eight electrons in a d subshell with n = 3. The three quantum numbers...

the energies of atomic orbitals

Shielding and Orbital Penetration

Shielding and orbital penetration help explain why electrons in an atom have different energies. Electrons are attracted to the positive nucleus, but they also repel one another in atoms with more than one electron. The strength of these forces depends on the charge and the distance between the particles. Opposite charges attract, like charges repel, and the force gets weaker as the particles move farther apart. An electron that stays closer to the nucleus is held more tightly. That means...

the aufbau principle and hund's rule

Electron Filling Order in Atomic Orbitals

Electron filling order in atomic orbitals follows the aufbau principle and Hund's rule. To write an electron configuration, we build atoms in order of atomic number. Starting with hydrogen and moving across the periods of the periodic table, one proton is added to the nucleus and one electron is placed into the correct subshell. This process describes the ground-state electron configurations of the elements. The aufbau principle comes from the German word aufbau, which means "to build up." It...

electron configuration of multielectron atoms

electron-configuration-of-multielectron-atoms

Valence Electrons and Noble Gas Shorthand

Valence electrons and noble gas shorthand help show how electrons are arranged in multielectron atoms. Sodium, the alkali metal with atomic number 11, has one more electron than neon. That extra electron goes into the lowest-energy subshell available, the 3s orbital, so sodium has the configuration 1s2 2s2 2p6 3s1. Electrons in the outermost shell, where n is highest, are called valence electrons. Electrons in the inner shells are called core electrons. Because core electrons often match a...

key terms and concepts

Explore light as an electromagnetic wave, including wavelength, frequency, amplitude, the speed of light, and examples from the electromagnetic spectrum.

Measuring Light with Wavelength and Frequency | JoVE K12

chemistry

JoVE Core Química da vida a los conceptos de química general mediante lecciones de vídeo basadas en animaciones, concisas y fáciles de entender. Además, en los vídeos de científicos en acción, se muestran experimentos de investigación clásicos y originales realizados en laboratorios de todo el mundo.

Pennsylvania State Academic Standards

9-12

Earth and Space Science

Earth's Systems

3.3.9-12.H

Space Systems

3.3.9-12.B

Weather and Climate

3.3.9-12.E

Physical Science

Waves and Electromagnetic Radiation

3.2.9-12.X

Louisiana Student Standards for Science

Earth Science

Earth’s Place In The Universe

HS-ESS1-1

HS-ESS1-2

Earth’s Systems

HS-ESS2-4

Energy

HS-PS3-3

ohios-learning-standards-and-model-curriculum

Ohio’s Learning Standards and Model Curriculum

Physics

Waves

Light phenomena

Tennessee Academic Standards

waves-and-their-applications-in-technologies-for-information-transfer

Waves and Their Applications in Technologies for Information Transfer

PHYS.PS4.7

CHEM1.PS4.1

Virginia  Standards of Learning

HIgh School

ES.2

ES.2.a

Arizona Science Standards

HS+C.P1

HS+C.P1U1.2

CHEM.6

CHEM.6.C

Alabama Course of Study Science

Matter and Its Interactions

9-12.C.1.1.c

Earth's Place in the Universe

9-12.ESS.1.2

9-12.ESS.1.2.a

9-12.ESS.1.2.b

Next Generation Science Standards

HS-PS4-1

HS-PS4-3

Earth’s Place in the Universe

Florida Department of Education

SC.912.E.5

SC.912.E.5.8

SC.912.P.8

SC.912.P.8.3

SC.912.P.12

SC.912.P.12.7

PHYS.9

PHYS.9.A

PHYS.9.C

PHYS.9.D

south-carolina-college-and-career-ready-science-standards

South Carolina College and Career Ready Science Standards

C-PS4-4

P-PS3-3

P-PS4-1

new-york-state-science-learning-standards

New York State Science Learning Standards

HS. Chemical Reactions

HS-PS1-7.

HS. Waves and Electromagnetic Radiation

HS-PS4-3.

The Atomic Theory of Matter

The earliest recorded discussion of the basic structure of matter comes from ancient Greek philosophers. Leucippus and Democritus argued that all matter ...

Subatomic Particles

Dalton was only partially correct about the particles that make up matter. All matter is composed of atoms, and atoms are composed of three smaller ...

Elements: Chemical Symbols and Isotopes

A chemical symbol is an abbreviation used to indicate an element or an atom of an element. For example, the symbol for mercury is Hg. The same symbol is ...

Ions and Ionic Charges

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The Periodic Table

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Atomic Mass

Atoms &mdash; and the protons, neutrons, and electrons that compose them &mdash; are extremely small. For example, a carbon atom weighs less than 2 ...

Molar Mass

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Periodic Classification of the Elements

The periodic table arranges atoms based on increasing atomic number so that elements with the same chemical properties recur periodically. When their ...

Types of Chemical Bonds

Chemical bonding theories were pioneered by American chemist Gilbert&#xA0;N. Lewis. He developed a model called the Lewis model to explain the type and ...

Ionic Bonding and Electron Transfer

Ions are atoms or molecules bearing an electrical charge. A cation (a positive ion) forms when a neutral atom loses one or more electrons from its valence ...

The Born-Haber Cycle

Lattice Energy&#xA0;

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trends-in-lattice-energy-ion-size-and-charge

Trends in Lattice Energy: Ion Size and Charge

An ionic compound is stable because of the electrostatic attraction between its positive and negative ions. The lattice energy of a compound is a measure ...

Covalent Bonding and Lewis Structures

Compared to ionic bonds, which results from the transfer of electrons between metallic and nonmetallic atoms, covalent bonds result from the mutual ...

Electronegativity

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Electronegativity values of ...

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Bond Polarity, Dipole Moment, and Percent Ionic Character

Bond Polarity

The absolute value of the difference in electronegativity (&Delta;EN) of two bonded atoms provides a rough measure of the polarity to be ...

lewis-structures-of-molecular-compounds-and-polyatomic-ions

Lewis Structures of Molecular Compounds and Polyatomic Ions

To draw Lewis structures for complicated molecules and molecular ions, it is helpful to follow a step-by-step procedure as outlined:


	Determine the ...

Bond Energies and Bond Lengths

Stable molecules exist because covalent bonds hold the atoms together. The strength of a covalent bond is measured by the energy required to break it, ...

Bonding in Metals

Metallic bonds are formed between two metal atoms. A simplified model to describe metallic bonding has been developed by Paul Dr&#xFC;de called the ...

Model basic atomic structure and relate an element's atomic structure to its bonding, reactivity, and placement on the Periodic Table.

IPC.7.A

physical-and-chemical-properties-of-matter

Physical and Chemical Properties of Matter

The characteristics that enable us to distinguish one substance from another are called properties.

Physical Properties of Matter

A physical property is ...

atomic-radii-and-effective-nuclear-charge

Atomic Radii and Effective Nuclear Charge

The elements in groups of the periodic table exhibit similar chemical behavior. This similarity occurs because the members of a group have the same number ...

Ionic Radii

Ionic radius is the measure used to describe the size of an ion. A cation always has fewer electrons and the same number of protons as the parent atom; it ...

Ionization Energy

The amount of energy required to remove the most loosely bound electron from a gaseous atom in its ground state is called its first ionization energy ...

Electron Affinity

The electron affinity (EA) is the energy change for adding an electron to a gaseous atom to form an anion (negative ion).



This process can be either ...

Use patterns within the Periodic Table to predict the relative physical and chemical properties of elements.

IPC.7.B

Science concepts. The student knows that relationships exist between the structure and properties of matter. The student is expected to:

Measuring Light with Wavelength and Frequency

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