Name: electromagnetic waves: uses across the spectrum
Uploaded: 2020-09-03T13:38:27.000Z
Duration: 2 min 37 s
Channel: JoVE

K12 Standards

Pennsylvania State Academic Standards

9-12

Earth and Space Science

Earth's Systems

3.3.9-12.H

The Electromagnetic Spectrum

الطيف الكهرومغناطيسي هو نطاق الترددات والأطوال الموجية المقابلة للإشعاع الكهرومغناطيسي. يتناسب الطول الموجي والتردد عكسيا لبعضهما البعض كلما كان الطول الموجي أطول،كلما انخفض التردد. طاقة الإشعاع الكهرومغناطيسي تتناسب طرديا مع تواترها،كما هو موضح في معادلة بلانك.وبالتالي،فإن الموجات الكهرومغناطيسية ذات أعلى طاقة لديها أقصر أطوال موجية. يتم تصنيف الموجات الكهرومغناطيسية مثل موجات الراديو،الموجات الدقيقة،الأشعة تحت الحمراء،الضوء المرئي،الأشعة فوق البنفسجية،الأشعة السينية أو أشعة جاما حسب تردداتها وأطوالها الموجية. موجات الراديو،والتي تستخدم لنقل الإشارات بين أنظمة الاتصالات،لديها أطول موجات،أقل ترددات وأقل قدر من الطاقة.تمتلك أشعة الميكروويف ثاني أطول أطوال موجية. تتراوح استخداماتهم من أنظمة الرادار لتسخين الطعام في المنزل. التالي هو الأشعة تحت الحمراء،وهي جزء مهم من الإشعاع الحراري المنبعث بواسطة الأشياء الدافئة.على سبيل المثال،تمتص الأرض الأشعة تحت الحمراء كجزء من الطاقة المشعة المنبعثة من الشمس،و تبعث الآرض نفسها الأشعة تحت الحمراء في الفضاء. الأطوال الموجية للضوء المرئي لا تزال أقصر،و تتراوح من 740 إلى 390 نانومتر. الضوء الأحمر له أطول طول موجي والبنفسجي له الأقصر.عيون الإنسان تستجيب فقط لهذا الطول الموجي الضيق النطاق. الأشعة فوق البنفسجية لها أطوال موجية أقصر. ضوء الشمس هو اكثر مصدر متعارف عليه للأشعة فوق البنفسجية،والتي لديها طاقة كافية لدرجة أن التعرض المفرط يسبب حروق الشمس وقد يؤدي إلى سرطان الجلد.الأشعة السينية وأشعة جاما لها أقصر أطوال موجية وهي أكثر أشكال الإشعاع الكهرومغناطيسي نشاطا. يمكن أن تمر الأشعة السينية عبر العديد من المواد،لكنها لا تمر عبر العظام بسهولة بالغة. هذا يجعلها أداة تصوير مهمة.تشتهر أشعة جاما بكونها تنطلق خلال سلاسل الاضمحلال لبعض العناصر المشعة. بينما لا يوجد تمييز عالمي بين جاما والأشعة السينية،فإنّأشعة جاما عادة تعتبر ذات الأطوال الموجية الأقصر،وأعلى ترددات،وأعلى الطاقات.

الطيف الكهرومغناطيسي

يتكون الطيف الكهرومغناطيسي من جميع أنواع الإشعاع الكهرومغناطيسي المرتبة وفقًا لترددها وطولتها الموجية. لكل لون من ألوان الضوء المرئي المتعددة ترددات وأطوال موجية معينة مرتبطة بها، ويمكنك أن ترى أن الضوء المرئي لا يشكل سوى جزء صغير من الطيف الكهرومغناطيسي. ولأن التكنولوجيات التي تم تطويرها للعمل في أجزاء مختلفة من الطيف الكهرومغناطيسي مختلفة، ولأسباب تتعلّق بالراحة والتراث التاريخي، فإن الوحدات المختلفة تستخدم عادة في أجزاء مختلفة من الطيف. على سبيل المثال، عادة ما يتم تحديد الموجات اللاسلكية على أنها ترددات (عادة بوحدات ميجا هرتز)، بينما يتم تحديد المنطقة المرئية عادة بأطوال موجية (عادة في وحدات نانومتر أو أنغستروم).  <img alt="Eq1" src="https://www.jovecore.com/CDNSource/lessons/975/975Image_1.png" style="width: 700px;" /> Figure 1: يُظهر أجزاء من الطيف الكهرومغناطيسي بترتيب زيادة التردد وتقليل الطول الموجي. أنواع الموجات الكهرومغناطيسية هي الموجات اللاسلكية والميكروويف والأشعة فوق البنفسجية والمرئية والأشعة تحت الحمراء الأشعة السينية وأشعة جاما. تحتوي الموجات اللاسلكية على أطول أطوال موجية، وأقل ترددات، وتحمل أقل كمية من الطاقة. وهي تستخدم في تكنولوجيا الهاتف الخلوي، والبث الإذاعي والتلفزيوني، ومراقبة الحركة الجوية، وما إلى ذلك الموجات متناهية الصغر لها أطوال موجية أقصر مقارنة بالموجات اللاسلكية. يتم امتصاصها بواسطة الماء ويتم استخدامها لتسخين الطعام وطهيه.  ثم هناك الأشعة تحت الحمراء التي تنبعث من الأجسام الدافئة. على سبيل المثال، تمتص الأرض الطاقة الإشعاعية من الشمس وتبعث إشعاعات بالأشعة تحت الحمراء. يتم امتصاص بعض الأشعة تحت الحمراء وإعادة انبعاث الغازات من الغلاف الجوي للحفاظ على متوسط درجة حرارة الأرض من خلال تأثير الاحتباس الحراري. ستشعر النظارات الواقية للرؤية الليلية بأشعة الأشعة تحت الحمراء التي تنبعث من أجسامنا. ولا يمثل الضوء المرئي سوى جزء صغير من الأشعة الكهرومغناطيسية التي تتراوح بين 740 و390 نانومتر. لا يمكن للعين  البشرية إلا أن ترى هذا النطاق الصغير من الأطوال الموجية. يتكون الضوء المرئي بشكل أساسي من سبعة مكونات ملونة، بما في ذلك الأحمر والبرتقالي والأصفر والأخضر. أزرق، وبنفسجي.  الإشعاع فوق البنفسجي له أطوال موجية تتراوح بين 400 إلى 10 نانومتر. إن أشعة الشمس هي المصدر الأكثر ألفة للإشعاع فوق البنفسجي. فهو يحمل طاقة كافية تؤدي، مع التعرض المفرط، إلى حروق الشمس. يمكن أن تمر الأشعة السينية عبر العديد من المواد، مما يجعلها أداة تصوير مهمة. يستخدم أطباء الأسنان الأشعة السينية لأغراض التشخيص، ويستخدمها أمن المطار لتصور المكونات في حقيبة. تحتوي أشعة جاما على أطوال موجية صغيرة وترددات عالية وطاقات. وتطلق أشعة غاما بفعل التفاعلات النووية والعناصر المشعة التي تحدث بشكل طبيعي. الأشعة السينية وأشعة جاما هي أكثر أشكال الإشعاع الكهرومغناطيسي حيوية. ويمكن لطاقاتها العالية تأين الذرات والجزيئات. يمكن أن يتسبب الإشعاع المؤين في حدوث تغير دائم أو تلف للجزيئات البيولوجية. وهي تستخدم لتدمير خلايا السرطان.    هذا النص مقتبس من <a href="https://openstax.org/books/chemistry-2e/pages/6-1-electromagnetic-energy">Openstax, Chemistry 2e, Section 6.1: Electromagnetic Energy.</a>

يتكون الطيف الكهرومغناطيسي من جميع أنواع الإشعاع الكهرومغناطيسي مرتبة وفقا لترددها وطولها الموجي. كل من ...

Education

JoVE Core

Chemistry

الكيمياء

واحد

Electronic Structure of Atoms

البنية الإلكترونية للذرات

KEY TERMS AND CONCEPTS

المصطلحات والمفاهيم الأساسية

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 have the longest wavelengths, the lowest frequencies, and the least energy. They are used in cell phones, radio and television broadcasts, and air-traffic control. Microwaves have shorter wavelengths than radio waves and are absorbed by water, which is why they can heat and cook food.

Infrared radiation is next and is emitted by warm objects. The Earth absorbs energy from the Sun and gives off infrared radiation. Some of this radiation is absorbed and re-emitted by the atmosphere, which helps keep Earth’s average temperature stable through the greenhouse effect. Night vision goggles also detect the infrared radiation that our bodies emit.

Visible light spans only about 740 to 390 nm, so the human eye can see just a narrow band of electromagnetic radiation. This band includes red, orange, yellow, green, blue, indigo, and violet. Ultraviolet radiation has wavelengths from about 400 to 10 nm. Sunlight is the most familiar source of UV radiation, and too much exposure can cause sunburn.

X-rays can pass through many materials, so they are useful for imaging. Dentists use x-rays for diagnosis, and airport security uses them to view what is inside a suitcase. Gamma rays have even smaller wavelengths, higher frequencies, and higher energies. They come from nuclear reactions and naturally occurring radioactive elements. X-rays and gamma rays are the most energetic forms of electromagnetic radiation, and their ionizing radiation can damage biological molecules. Because of that, they can be used to destroy cancer cells.

Electromagnetic Waves: Uses Across the Spectrum

electromagnetic-waves-uses-across-the-spectrum

the wave nature of light

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...

the electromagnetic 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 the electromagnetic spectrum from radio waves to gamma rays, including visible light, infrared, UV, X-rays, and their real-world uses.

Electromagnetic Waves: Uses Across the Spectrum | JoVE K12

chemistry

JoVE Core Chemistry brings general chemistry concepts to life using concise and easy-to-understand animated video lessons. Plus, in the scientist-in-action videos, we demonstrate classical and original research experiments performed in today's laboratories worldwide.

Weather and Climate

3.3.9-12.E

Physical Science

Waves and Electromagnetic Radiation

3.2.9-12.X

Louisiana Student Standards for Science

High School

Earth Science

Earth’s Systems

HS-ESS2-4

Tennessee Academic Standards

Physics

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

Waves and Their Applications in Technologies for Information Transfer

PHYS.PS4.7

PHYS.PS4.8

Arizona Science Standards

HS+C.P1

HS+C.P1U1.2

new-jersey-student-learning-standards-for-science

New Jersey Student Learning Standards for Science

HS-PS4-4

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

Next Generation Science Standards

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.10

SC.912.P.10.19

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

South Carolina College and Career Ready Science Standards

C-PS4-4

C-PS4-5

P-PS4-4

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.

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Students who demonstrate understanding can analyze geoscience data to make the claim that one change to Earth's surface can create feedback that causes changes to other Earth systems.  Clarification Statement: Examples should include climate feedbacks, such as how an increase in greenhouse gases causes a rise in global temperatures that melts glacial ice, which reduces the amount of sunlight reflected from Earth's surface, increasing surface temperatures and further reducing the amount of ice.  Examples could also be taken from other system interactions, such as how the loss of ground vegetation causes an increase in water runoff and soil erosion;  how dammed rivers increase groundwater recharge, decrease sediment transport, and increase coastal erosion;  or how the loss of wetlands causes a decrease in local humidity that further reduces the wetland extent.  Assessment Boundary:

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Igneous Volcanic Rock

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An Overview of Alkenone Biomarker Analysis for Paleothermometry

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Making a Geologic Cross Section

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Conditions on Early Earth

Nuclear Stability

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Radioactivity and Nuclear Equations

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Radioactive Decay and Radiometric Dating

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Isotopes and Radioisotopes

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Nuclear Fusion

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Nuclear Transmutation

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Determining Spatial Orientation of Rock Layers with the Brunton Compass

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Dynamics of Structures

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Sound Waves and Doppler Shift

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Reflection of Waves

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Students who demonstrate understanding can develop a model based on evidence of Earth's interior to describe the cycling of matter by thermal convection.  Clarification Statement: Emphasis is on both a one-dimensional model of Earth, with radial layers determined by density, and a three-dimensional model, which is controlled by mantle convection and the resulting plate tectonics.  Examples of evidence include maps of Earth's three-dimensional structure obtained from seismic waves, records of the rate of change of Earth's magnetic field (as constraints on convection in the outer core), and identification of the composition of Earth's layers from high-pressure laboratory experiments.  Assessment Boundary:

3.3.9-12.I

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The Water Cycle

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Cohesion

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The reaction between a Br&#248;nsted-Lowry acid and water is called acid ionization. For example, when hydrogen fluoride dissolves in water and ionizes, ...

The potential of hydrogen (pH) is a measure of the acidity or basicity of a water-based solution determined by the concentration of hydronium ions (H3O+). ...

Students who demonstrate understanding can plan and conduct an investigation of the properties of water and its effects on Earth materials and surface processes. [cite: 44] Clarification Statement: Emphasis is on mechanical and chemical investigations with water and a variety of solid materials to provide the evidence for connections between the hydrologic cycle and system interactions commonly known as the rock cycle. [cite: 45] Examples of mechanical investigations include stream transportation and deposition using a stream table, erosion using variations in soil moisture content, or frost wedging by the expansion of water as it freezes. [cite: 46] Examples of chemical investigations include chemical weathering and recrystallization (by testing the solubility of different materials) or melt generation (by examining how water lowers the melting temperature of most solids). [cite: 47] Assessment Boundary:

3.3.9-12.K

Electromagnetic Waves: Uses Across the Spectrum

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