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

הספקטרום האלקטרומגנטי הוא טווח התדירויות ואורכי הגל התואמים של קרינה אלקטרומגנטית. אורך הגל והתדירות עומדים ביחס הפוך זה לזה. ככל שגל ארוך יותר, כך התדירות שלו נמוכה יותר.אנרגיית הקרינה האלקטרומגנטית נמצאת ביחס ישר לתדירות הגל, כפי שממחישה המשוואה של פלאנק. לכן הגלים בעלי האנרגיה האלקטרומגנטית הגבוהה ביותר הם בעלי אורכי הגל הקצרים ביותר. גלים אלקטרומגנטיים מתחלקים כגלי רדיו, מיקרוגל, אינפרא אדום, אור נראה, קרני אולטרה סגול, רנטגן או גמא בהתאם לתדרים ולאורכי הגל שלהם.גלי רדיו, המשמשים להעברת אותות בין מערכות תקשורת הם בעלי אורכי הגל הארוכים ביותר, התדירויות הנמוכות ביותר וכמות האנרגיה הקטנה ביותר. אורכי הגל של גלי מיקרוגל הם השניים באורכם. השימושים בהם נעים בין מערכות מכ"ם לחימום אוכל בבית.הגלים הבאים הם גלי קרינת אינפרא אדום, המהווים חלק משמעותי מהקרינה התרמית הנפלטת על ידי חפצים חמים. לדוגמה, כדור הארץ גם סופג קרינה אינפרא אדומה כחלק מאנרגיית הקרינה הנפלטת על ידי השמש וגם פולט בעצמו קרינה אינפרא אדומה למרחב. אורכי הגל של האור הנראה הם קצרים יותר, ונעים בין 740 ל-390 ננומטרים.לאור אדום יש את אורכי הגל הארוכים ביותר ולסגול, הקצרים ביותר. עיניים אנושיות מגיבות רק לטווח אורכי גל צר זה. הקרינה האולטרה סגולה מאופיינת באורכי גל קצרים עוד יותר.אור השמש הוא המקור המוכר ביותר של קרינה אולטרה סגולה, ויש בה די אנרגיה כך שחשיפה מוגזמת עלולה לגרום לכוויות שמש ולסרטן העור. קרני רנטגן וגמא מאופיינים באורכי הגל הקצרים ביותר והם הצורות האנרגטיות ביותר של קרינה אלקטרומגנטית. קרני רנטגן יכולות לעבור דרך חומרים רבים, אבל הן לא חודרות בקלות רבה עצמות.תכונות אלה הופכות אותן לכלי הדמיה חשוב. קרני גמא ידועות בעיקר כקרניים המשוחררות במהלך שרשראות הפירוק של יסודות רדיואקטיביים מסוימים. בעוד שאין אבחנה אוניברסלית בין קרני גמא לקרני רנטגן, קרני גמא בדרך כלל נחשבות לבעלות אורכי הגל הקצרים ביותר, התדירויות הגבוהות ביותר והאנרגיות הגבוהות ביותר.

הספקטרום האלקטרומגנטי

<div style="direction:rtl">הספקטרום האלקטרומגנטי מורכב מכל סוגי הקרינה האלקטרומגנטית המסודרים לפי תדירותם ואורך הגל שלהם. לכל אחד מהצבעים השונים של האור הנראה יש תדרים ואורכי גל ספציפיים הקשורים אליהם, וניתן לראות שאור הנראה מהווה רק חלק קטן מהספקטרום האלקטרומגנטי. מכיוון שהטכנולוגיות שפותחו כדי לעבוד בחלקים שונים של הספקטרום האלקטרומגנטי שונות, מטעמי נוחות ומורשת היסטורית, יחידות שונות משמשות בדרך כלל לחלקים שונים של הספקטרום. לדוגמה, גלי רדיו מצוינים בדרך כלל כתדרים (בדרך כלל ביחידות של מגה-הרץ), בעוד שהאזור הנראה מצויין בדרך כלל באורכי גל (בדרך כלל ביחידות של ננומטר או אנגסטרם). <img alt="Eq1" src="https://www.jove.com/files/core/CDNSource/lessons/975/975Image_1.png" style="width: 700px;"> איור 1: חלקים מהספקטרום האלקטרומגנטי מוצגים לפי סדר הגדלת התדר ואורך הגל פוחת. סוגי הגלים האלקטרומגנטיים הם גלי רדיו, מיקרוגל, אולטרה סגול, גלוי, אינפרא אדום, קרני רנטגן וקרני גמא. לגלי רדיו יש את אורכי הגל הארוכים ביותר, את התדרים הנמוכים ביותר, והם נושאים את כמות האנרגיה הנמוכה ביותר. הם משמשים בטכנולוגיית טלפונים סלולריים, שידורי רדיו וטלוויזיה, בקרת תנועה אווירית וכו'. למיקרוגלים יש אורכי גל קצרים יותר בהשוואה לגלי הרדיו. הם נספגים במים ומשמשים לחימום ובישול מזון. לאחר מכן קרינה אינפרא אדומה, הנפלטת מאובייקטים חמים. לדוגמה, כדור הארץ סופג אנרגיית קרינה מהשמש ופולט קרינה אינפרא אדומה. חלק מקרינה אינפרה אדומה נספגת ונפלטת מחדש על ידי האטמוספירה כדי לשמור על הטמפרטורה הממוצעת של כדור הארץ באמצעות אפקט החממה. משקפי ראיית לילה חשים את קרינת האינפרא האדומה הנפלטת מגופנו. האור הגלוי הוא רק חלק זעיר של קרינה אלקטרומגנטית הנעה בין 740 ל-390 ננומטר. עיניים אנושיות יכולות לראות רק את הטווח הקטן הזה של אורכי גל. האור הגלוי מורכב בעיקר משבעה מרכיבי צבע, כולל אדום, כתום, צהוב, ירוק, כחול, אינדיגו וסגול. לקרינה אולטרה סגולה יש אורכי גל הנעים בין 400 ל-10 ננומטר. אור השמש הוא המקור המוכר ביותר לקרינת UV. הוא נושא מספיק אנרגיה שבחשיפה מוגזמת הוא גורם לכוויות שמש. צילומי רנטגן יכולים לעבור דרך חומרים רבים, מה שהופך אותם לכלי הדמיה חשוב. רופאי שיניים משתמשים בקרני רנטגן למטרות אבחון, ואבטחת שדות התעופה משתמשת בהם כדי לראות רכיבים במזוודה. לקרני גמא יש אורכי גל קטנים יותר, תדרים גבוהים ואנרגיות. קרני גמא משתחררות על ידי תגובות גרעיניות ויסודות רדיואקטיביים טבעיים. קרני רנטגן וקרני גמא הן הצורות האנרגטיות ביותר של קרינה אלקטרומגנטית. האנרגיות הגבוהות שלהם יכולות ליינן אטומים ומולקולות. הקרינה המייננת עלולה לגרום לשינוי קבוע או נזק למולקולות ביולוגיות. הם משמשים להשמדת תאים סרטניים. טקסט זה מותאם מ <a href="https://openstax.org/books/chemistry-2e/pages/6-1-electromagnetic-energy">Openstax, Chemistry 2e, Section 6.1: Electromagnetic Energy.</a></div>

הספקטרום האלקטרומגנטי מורכב מכל סוגי הקרינה האלקטרומגנטית המסודרים על פי תדירותם ואורך הגל שלהם. כל אחד ...

Education

JoVE Core

Chemistry

כימיה

אחד

Electronic Structure of Atoms

מבנה אלקטרוני של אטומים

KEY TERMS AND CONCEPTS

מונחים ומושגים מרכזיים

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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Isotopes and Radioisotopes

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Nuclear Transmutation

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Source: Arianna Brown,&#160;Asantha Cooray, PhD, Department of Physics &#38; Astronomy, School of Physical Sciences, University of California, Irvine, CA
...

Reflection of Waves

When a wave travels from one medium to another, it gets reflected at the boundary of the second medium. A common example of this is when a person yells at ...

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

Role of Water in Human Biology

Water is the one of the most significant components of the human body; it plays a crucial role in several physiological activities because of its unique ...

States of Water

Water exists in any one of the three classical states: solid (ice), liquid (water), and gas (steam or water vapor). The state of water depends on i) the ...

The Water Cycle

The Earth&rsquo;s hydrosphere includes all of the areas where the storage and movement of water occurs. Since water is the basis of all living processes, ...

Cohesion

Cohesion is the attraction between molecules of the same type, such as water molecules. Water molecules have an overall neutral charge but are polar ...

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 ...

Chemistry of the Cell

The cell is chemically composed of water, organic molecules and inorganic ions.
Water
The polarity of the water molecule and its resulting hydrogen ...

Water: A Bronsted-Lowry Acid and Base

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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