The Electromagnetic Spectrum 1 What is the Electromagnetic

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The Electromagnetic Spectrum 1

The Electromagnetic Spectrum 1

What is the Electromagnetic Spectrum? The electromagnetic spectrum is the complete spectrum (or continuum)

What is the Electromagnetic Spectrum? The electromagnetic spectrum is the complete spectrum (or continuum) of all forms of “light” An electromagnetic wave consists of electric and magnetic fields which vibrate - thus making waves. Vibrations 2

What is the Electromagnetic Spectrum? The electromagnetic spectrum consists of: radio waves cell phone

What is the Electromagnetic Spectrum? The electromagnetic spectrum consists of: radio waves cell phone waves microwaves radar waves infrared waves visible light waves ultraviolet waves x-ray waves gamma waves The Electromagnetic Spectrum 3

The Electromagnetic Spectrum 4

The Electromagnetic Spectrum 4

C) Wavelength: distance between one point on the wave and the nearest point where

C) Wavelength: distance between one point on the wave and the nearest point where the wave repeats itself 1) This can be measured from crest-to-crest, trough-to-trough, or from the start of a wave to the start of the next one. 2) Symbol for wavelength is λ

D) Amplitude: maximum displacement from the undisturbed position of the medium to the top

D) Amplitude: maximum displacement from the undisturbed position of the medium to the top of a crest.

E) Period (T): time required for one wave to complete one full cycle of

E) Period (T): time required for one wave to complete one full cycle of its motion i. e. The period measures how long it takes for a wave to pass by 1) Example: From its highest point to its lowest and back again 2) Measured in seconds (s)

F) Frequency: the number of complete waves that pass a point in a given

F) Frequency: the number of complete waves that pass a point in a given time. It has the symbol f. 1) SI Units: Hertz (Hz) 2) Hertz units measure the number of vibrations per second

G) Wave speed 1) The frequency and wavelength are related to one another and

G) Wave speed 1) The frequency and wavelength are related to one another and to the speed of the wave by the following formula, where “v” is equal to the speed: Speed = Wavelength x Frequency v = f

Waves Properties of electromagnetic waves include speed, frequency and wavelength Speed (s), frequency (f)

Waves Properties of electromagnetic waves include speed, frequency and wavelength Speed (s), frequency (f) and wavelength ( ) are related in the formula: s=f x All light waves travel at a speed of 3 x 108 m/s in a vacuum The Electromagnetic Spectrum 10

Relationship Between Wavelength & Frequency All parts of the electromagnetic spectrum travel at the

Relationship Between Wavelength & Frequency All parts of the electromagnetic spectrum travel at the same speed Therefore, wavelength and frequency have an indirect relationship. This means that as one characteristic increases, the other decreases In other words, as wavelength increases, frequency decreases The Electromagnetic Spectrum 11

Relationship Between Wavelength & Frequency As wavelength decreases, frequency will? increase See the relationship

Relationship Between Wavelength & Frequency As wavelength decreases, frequency will? increase See the relationship The Electromagnetic Spectrum 12

Wavelength, Frequency, Energy Electromagnetic wave characteristics: • short wavelengths have a high frequency •

Wavelength, Frequency, Energy Electromagnetic wave characteristics: • short wavelengths have a high frequency • long wavelengths have a low frequency Electromagnetic waves & Energy: • high frequency waves have high energy • low frequency waves have low energy The Electromagnetic Spectrum 13

Wavelength, Frequency, Energy Fill in the table below: wavelength frequency energy long high The

Wavelength, Frequency, Energy Fill in the table below: wavelength frequency energy long high The Electromagnetic Spectrum 14

Wavelength & Energy smaller wavelengths increasing frequency increasing energy If you haven’t already, sketch

Wavelength & Energy smaller wavelengths increasing frequency increasing energy If you haven’t already, sketch this drawing into your notes. Don’t worry so much about the actual wavelengths, just get the general shape and where the various forms of light (radio, infrared, x-ray, etc) exist. The Electromagnetic Spectrum 15

The Electromagnetic Spectrum 16

The Electromagnetic Spectrum 16

Radio waves Low energy waves with longest wavelengths Includes FM, AM, radar and TV

Radio waves Low energy waves with longest wavelengths Includes FM, AM, radar and TV waves Wavelengths of 1 m (10 -1 m) and longer Low frequency Used in many devices such as remote control items, cell phones, wireless devices, etc. The Electromagnetic Spectrum 17

Microwaves Only radio waves are longer Wavelength 1 x 10 -1 m to 1

Microwaves Only radio waves are longer Wavelength 1 x 10 -1 m to 1 x 10 - 4 m (1 m to 0. 001 m) used for communication, medicine and consumer use (microwave ovens) The Electromagnetic Spectrum 18

Infrared waves Invisible electromagnetic waves that are detected as heat Can be detected with

Infrared waves Invisible electromagnetic waves that are detected as heat Can be detected with special devices such as night goggles Used in heat lamps Higher energy than microwaves but lower than visible light The Electromagnetic Spectrum 19

Visible Light The portion of the electromagnetic spectrum that human eyes can detect ROY

Visible Light The portion of the electromagnetic spectrum that human eyes can detect ROY G BIV (red, orange, yellow, green, blue, indigo, violet) Which color has the lowest frequency? red has the lowest frequency – violet the highest The Electromagnetic Spectrum 20

The Electromagnetic Spectrum 21

The Electromagnetic Spectrum 21

Ultraviolet waves Higher energy than light waves Can cause skin cancer and blindness in

Ultraviolet waves Higher energy than light waves Can cause skin cancer and blindness in humans Used in tanning beds and sterilizing equipment The Electromagnetic Spectrum 22

X-Rays High energy waves Used in medicine, industry and astronomy Can cause cancer The

X-Rays High energy waves Used in medicine, industry and astronomy Can cause cancer The Electromagnetic Spectrum 23

Gamma rays Highest energy Blocked from Earth’s surface by atmosphere The Electromagnetic Spectrum 24

Gamma rays Highest energy Blocked from Earth’s surface by atmosphere The Electromagnetic Spectrum 24

The Electromagnetic Spectrum 25

The Electromagnetic Spectrum 25

III. ) Doppler Effect: an observed change in the frequency of a wave when

III. ) Doppler Effect: an observed change in the frequency of a wave when the source or observer is moving A) Pitch of a sound (how high or low it is) is determined by the frequency at which the sound waves strike the eardrum 1) When an object that is emitting sound waves (i. e. ambulance) is at rest, the sound waves spread out in circles and anyone who is standing near the object will hear the same pitch

IV) Wave Interactions A) Reflection: the bouncing back of a ray of light, sound,

IV) Wave Interactions A) Reflection: the bouncing back of a ray of light, sound, or heat when the ray hits a surface that it does not go through B) Refraction: the bending of waves at an angle when they pass from one medium into another 1) Ex: Spoon in glass of water appears to be broken because the light waves are bending at a different angle when they enter the water versus the air

Time to remember. . . ① What is the relationship between frequency and wavelength?

Time to remember. . . ① What is the relationship between frequency and wavelength? ① What characteristic of gamma waves gives them their high energy? ① What does ROY G BIV mean? What part of the electromagnetic spectrum does it refer to? The Electromagnetic Spectrum 28

Time to Think ④ Which color is more energetic, red or yellow? ⑤ Which

Time to Think ④ Which color is more energetic, red or yellow? ⑤ Which type of wave travels faster, gamma or radio? ⑥ Why are microwaves more dangerous than radio waves? The Electromagnetic Spectrum 29

Apply What You Know ⑦ You have just been involved in a traffic incident

Apply What You Know ⑦ You have just been involved in a traffic incident that leaves you stranded on the side of the road. Which part of the electromagnetic spectrum would be of the most use to you and why? The Electromagnetic Spectrum 30

Answers ① Frequency and wavelength are properties of waves and since speed is constant

Answers ① Frequency and wavelength are properties of waves and since speed is constant for em waves, as frequency increases, wavelength decreases. In other words, they have an indirect relationship. ① Gamma waves get their high energy from their extremely short wavelengths (or extremely fast frequency) ① ROY G BIV stands for “red, orange, yellow, green, blue, indigo, and violet. They are the colors of the visible light in order of longest wavelength to shortest wavelength. ① Yellow is more energetic than red because it has a shorter wavelength (or larger frequency) ① Gamma waves and radio waves travel at the same speed ① Microwaves are more dangerous than radio waves because they have a higher frequency and carry more energy. The Electromagnetic Spectrum 31

More Great Science from The Science Vault If you enjoyed this powerpoint, you might

More Great Science from The Science Vault If you enjoyed this powerpoint, you might also enjoy these best-selling products: Chemical Bonding Go Fish – making chemical bonding less abstract and more fun; several different games differentiated for ability levels grades 8 - 12 Scientific Method / Experimental Design Unit – everything you need to teach (or review) experimental design: powerpoints, worksheets, quizzes Continental Drift and Plate Tectonics Powerpoint – 50 interactive slides that introduce continental drift and plate tectonics with links to website & flash animations The Life Cycle of Stars Powerpoint – gorgeous photos and videos bring this powerpoint alive for your students THE FINE PRINT © Jan Parker, 2009 – for purchaser’s classroom use only; please do not distribute. For more great science and classroom management materials, follow me at http: //www. thesciencevault. net, or on twitter @thesciencevault, or head over to my web store http: //www. teacherspayteachers. com/Store/The. Science-Vault If you put your classroom materials on a server for your students, please post this presentation in pdf form. Thanks! The Electromagnetic Spectrum 32