Light. Light is a Particle. Light can travel through the vacuum of space, but waves can t travel in a vacuum. So light must be a particle!

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1 Light Light is Wve Light is refrted in lenses. Light diffrting round two fingers (look lose) uses s of drkness: destrutive interferene. Light must e wve! Light is Prtile Light n trvel through the vuum of spe, ut wves n t trvel in vuum. So light must e prtile! Light is Both This ontrdition perplexed sientists for mny, mny yers, ut the evidene must e elieved: light is oth wve nd prtile. Pkets of light we ll photons. Speed of Light: 3 x 10 8 m/se Origins of Light nd Color Sound is fst: 340 m/se, ut light is fster: 3 x 10 8 m/se! Tht s 3 with 8 zeroes or 300,000,000 m/se. Light n irle the erth 27 times in one seond! Sientists now elieve tht nothing n go fster thn light. The speed of light is the ultimte speed limit. Photons (light) ome from eletrons flling from high eletron orits to low orits. These orits re lso lled energy levels. 8p 10 Energy n rise n eletron to higher energy level. energy in 8p 10 When the eletron flls k, photon is given off: light! photon out (lue) Beuse eh element hs different numer of protons, eh element hs slightly different eletron energy levels nd gives off different olors. From their olors we n tell the hemil mkeup of strs. The sky is lue euse oxygen toms give off lue photons. Visile Light White light in Prism Wht we ll visile light is mde up of mny different olors. Eh olor hs different wvelength nd different frequeny. Rinow out Red Ornge Yellow Green Blue Indigo Violet A prism uses refrtion to seprte the different wvelengths (olors) of visile light. The first letters spell: ROY G BIV Colors hve Different Energies You know tht different olor flmes give off different mounts of het. Red flmes re the oolest nd lue flmes re the hottest. As you move from Red to Blue, light GAINS energy. White light is mde up of ll olors. Tht is why white flme is the hottest! EM Spetrum Visile Light is very smll prt of the entire Eletromgneti (EM) Spetrum. Rdio wves Mirowves Infrred Visile Ultr- X-rys Gmm Light violet Rys Low Energy Low Frequeny Long Wvelength wht we n see Red Ornge Yellow Green Blue Indigo Violet High Energy High Frequeny Short Wvelength Rdio wves used to trnsmit rdio nd television signls. Wvelengths rnge from hundreds of meters to less thn entimeter. This is why rdio towers hve to e so tll. Mirowves used to ook food nd y ell phones. Wvelengths rnge from 30 m to 1 mm. Infrred (invisile het) 1 mm to 700 nnometers (700 illionths of meter). Visile (white) light from 700 to 400 nnometers. stephenmurry.om Ultrviolet light invisile wvelengths from 400 nnometers to 10 nnometers. Prt of sunlight urns your skin nd n use ner. The ozone lyer protets us from most of the sun s ultrviolet light. X-rys Used in mediine nd industry. Wvelengths re from 10 nnometers to.01 nnometers (10 trillionth of meter). Gmm rys the most powerful nd dngerous form of rdition. Wvelengths less thn.01 nnometers. Emitted y nuler retions, they n rek hemil nd nuler onds.

2 1. Photon 2. 3 x 10 8 m/se 3. Prism 4. Light A. The fstest speed in the universe: the speed of light. B. An orit of eletrons. To move from low to high requires energy. C. All light: visile nd invisile. D. Used to seprte white light into its olors. 1. Rdio wves 2. Infrred 3. Ultrviolet 4. X-rys A. Eletromgneti wves we feel s het. B. Dngerous EM wves tht hve very high energy nd ome from nuler retions. C. EM wves tht hve very low energy nd long wvelengths. D. EM wves tht n pss through skin nd hve short wvelengths. 5. EM Spetrum 6. Energy Level E. A single prtile or pket of light. F. A wve tht n trvel through vuum. 5. Gmm rys 6. Mirowves E. EM wves with more energy thn visile light nd n use sunurns. F. Long wvelengths; used in ell phones. Is light wve or prtile. Prove your nswer: Put these three in order from slowest to fstest: Light wves; sound wves; wter wves. Where does light ome from? Put these from shortest to longest wvelengths Rdio wves Ultrviolet X-rys Visile Mirowves Why do we see lightening nd her the thunder few seonds lter? Put these from lest energy to most energy. Rdio wves Ultrviolet X-rys Visile Mirowves Find the period of 10 Hz wve. If wve s fifth hrmoni hs frequeny of 35 Hz, wht is its nturl frequeny nd wht is the frequeny of H 3? A wve hs these hrteristis: 25 Hz nd 8 m. Find speed. Find its period: A sound hnges from 25 db to 5 db. How do we her the hnge? You her thunder 3 seonds fter you see the lightening. How fr wy is the storm? Wht hrmoni is this? Mrk the nodes nd nti-nodes. Mrk one wvelength on the hrmoni. Cn humns her this frequeny? You re in onert hll nd yell up to the eiling. It tkes 1 seond for the eho to ome k to you. How high is the eiling? Find the fundmentl frequeny: 3rd hrmoni frequeny: 40 Hz stephenmurry.om

3 Optis The Study of Light Refrtion Light slows down in glss. Here the left side slows down first using the light to end to the left. GLASS Light speeds up in ir. Here the left side speeds up first using the light to end to the right. Light refrts when pssing etween two sustnes t n. light ry The right side hits first nd slows down: ends to the right. GLASS GLASS If the light does not enter t n, it does not end. Refletion Norml n imginry 90 o (perpendiulr to surfe. Angle of Inidene the etween the inoming ry nd the norml. Angle of Refletion the etween the outgoing ry nd the norml. Light reflets t shiny oundries we ll mirrors. norml (90 o to mirror) of inidene 60 o 60 o of refletion MIRROR of inidene = of refletion Fous Every lens or mirror hs ple where ll of the prllel rys will meet. This is known s the fol point or fous. fol point or fous Stright Lines Mirrors nd lenses n mke things look igger or smller euse our eyes lwys think tht light omes from stright s, even if they hve een refrted or refleted. ir wter imge Ojet vs. Imge The is wht you re looking t: the tul thing. The imge is wht you think you see: the enlrged, redued, or moved. Lenses Lenses work y refrtion, y the light ending when moving etween two sustnes. A onvex lens mgnifies. Lenses nd mirrors work opposite of eh other. If onve lens redues, then onve mirror mgnifies. Conve or Convex onve Conve looks like the sides hve ved in. Mirrors Mirrors work y refletion, y the ounding of light off of shiny surfe. Imges in mirrors lwys look twie s fr wy s the. Ex. An imge looks 20 m wy in mirror. How fr wy is the? Answer: Hlf the distne: 10 meters. A onvex mirror redues. imge onvex lens A onvex lens is onvergent the light rys ome together. imge A onve lens redues. onve lens A onve lens is divergent the light rys spred prt. Convex the middle is igger thn the ends. onvex Optil Systems Mirosopes nd telesopes re optil systems tht use omintions of lenses nd/or mirrors to mgnify light. Comining optil devies llows us to see very distnt or very smll s. imge onvex mirror A onvex mirror is divergent. A onve mirror mgnifies imge onve mirror A onve mirror is onvergent.

4 Misellneous Light Topis Totl Internl Refletion Light usully psses through ler oundries, ut if it strikes t n greter thn the ritil will sty inside the medium (glss, ir, et.). Totl internl refletion is when ll the light is refleted k inside the medium. The ritil for glss is out 41 o. glss tue Totl Internl Refletion: light pst the ritil nnot espe. Fier Optis Fier optis work y totl internl refletion. Fier optis pss light through flexile glss or plsti tues (lled fiers). These tues n e ent llowing light to e direted where it is wnted. Fier opti sopes n see round orners. Fier opti les rry muh of the ommunitions of our world (Internet nd phone) euse it trvels t the speed of light. Inndesent Light Inndesent (norml )light uls mke light y very high het. The filment glows right when enough eletriity flows through it. Inndesent light is very ineffiient euse most of the energy is lost s het. filment Inndesent Lightul Types of Lights Fluoresent Lightul Fluoresent lights re four times more effiient thn inndesent uls. 3/4 of the energy of n inndesent ul is lost to het. Fluoresent Light In fluoresent light uls eletriity exites gs inside, emitting mostly UV light. The white oting on the outside of the ul sors the UV light nd emits white light. Light is trnsverse wve (virting 90 o to the diretion of motion). Norml light is hoti, with trnsverse wves moving in ll diretions. A polrizer llows only light going one diretion to go through (like om). norml light polrizer Polriztion polrized light 2nd polrizer turned 90 o no light gets through 2nd polrizer Only light in one diretion n get through polrizer. Two polrizers turned 90 o n nel out ll light. Polriztion lso llows smll omputers nd lultors sreens to mke letters nd imges. Polriztion is used in some sunglsses to redue glre. Glow-in-the-Drk Lsers LASER Light Amplifition y Stimulted Emission of Rdition Glow-in-the-drk (photoluminesent) s ontin the element phosphorous. When phosphorous eletrons re energized, they ome down few t time, giving off light over time. When ll the eletrons hve fllen the phosphorous goes drk. Visile light rehrges them (rising them up) so tht they give off light gin. How Lsers Work Lsers give off light of one prtiulr wvelength. This omes from foring sustne (usully gs) to give off light. This light ounes k nd forth etween mirrors, using other toms to give off more light. When the light is powerful enough it espes s lser em. prism Compt lser light refrts, ut does not spred out in prism. Why We Use Lsers Phosphorous toms give off light grdully, seeming to glow-in-the-drk. Lser light is ompt: it doesn t spred out like regulr light. Tht s why we use them for pointers nd why they don t end in prisms. Lsers n e powerful. Some lsers re used industry nd mediine for preision utting. Militry lsers re just now le to low up inoming missiles.

5 1. Totl internl refletion 2. Critil 3. Fier optis 4. Inndesent 5. Fluoresent 6. Filment A. Light reted from high het. B. The prt of light ul tht glows when hot nd mkes inndesent light. C. When ll light nnot espe glss or nother medium nd stys inside. D. The pst whih light nnot espe. E. Tehnology sed on ending light in les. F. Effiient light from UV rdition. How n light e redireted y fier optis? Cn fier opti le e ent ny diretion? Why or why not? 1. Polriztion 2. Polrizer 3. Photoluminesene 4. Phosphorous 5. Lser lens A. An tht sreens out ll ut light in one diretion. B. Light mplifition y stimulted emissions of rdition. C. An element tht releses light slowly; used in glow-in-the-drk s. D. The t of only llowing one-diretionl light to pss through filter. E. Ojets tht give off light slowly. Show where the 3 light rys will go. Conve or onvex lens? Wht do we ll the dot? Mgnifying or reduing? Convergent or divergent? You hve n offie uilding nd need to ut ost. Wht kind of lights will you use nd why? Light is pssed through polrizer. How ould you nel out light with seond polrizer? Wht element is photoluminesent nd why? mirror Use RGB to mke these olors. Cyn Yellow White Blk Green Mgent Show where the light will go. Conve or onvex mirror? Mgnifying or reduing? Convergent or divergent? Use CMYK to mke these olors. Blue Red White Blk Green Mgent Why don t lsers spred out into rinow in prism? A onvex lens is onvergent/divergent nd mgnifies/redues. A onve lens is onvergent/divergent nd mgnifies/redues. A onvex mirror is onvergent/divergent nd mgnifies/redues. A onve mirror is onvergent/divergent nd mgnifies/redues. Angle of inidene: Angle of refletion: Norml: Inident ry: Refleted ry: M i rr or d If the of inidene is 25 o, wht is the of refletion? If the etween the inident nd refleted rys is 80 o, wht is the of refletion? If n imge look 20 meters wy in mirror how fr wy is the? An is 4 meters wy from mirror. How fr wy does the imge look? Using CMYK Wht olor does yellow sor? Wht olors does yn reflet? Wht hs more energy: Rdio wves or Visile light? Wht hs shorter wvelength: Ultrviolet or Gmm rys? Wht hs higher frequeny: Visile light or Infrred? A sound wve hs period of 0.5 ses. Find its frequeny. Find the wvelength of the ove wve. If the fourth hrmoni of stnding wve is 48 Hz, find the fundmentl frequeny. You her your eho 6 seonds fter you yell into nyon. How wide is the nyon?

6 1. Optis 2. Imge 3. Ojet 4. Conve 5. Convex 6. Convergent 7. Divergent A. The study of how light ehves. B. A lens or mirror tht is igger in the middle. C. Light rys tht spred prt. D. Where your eyes think something is. E. Light rys tht ome together. F. Wht you re tully looking t. G. A lens or mirror tht is igger t the ends. 1. Norml 2. Mirror 3. Angle of inidene 4. Angle of refletion 5. Lens 6. Fous A. A drwn perpendiulr to the surfe of mirror or lens. B. An optil devie tht works y refrtion to end light. C. From the norml to the inoming ry. D. From the norml to the outgoing ry. E. Where ll prllel rys ome together. F. An optil devie tht works y refletion. The of inidene is: The of refletion is: The norml is: The inident ry is: The refleted ry is: A onvex lens is onvergent/divergent nd mgnifies/redues. A onve lens is onvergent/divergent nd mgnifies/redues. A onvex mirror is onvergent/divergent nd mgnifies/redues. A onve mirror is onvergent/divergent nd mgnifies/redues. Wht quntities re these units for? m mi m s 2 hr s volts Kg Km Meters Joules Se Wtts Ω N Amps Hz If sound is 60 db loud. Answer how mny db these would e: 1) A sound twie s loud: 2) A sound hlf s loud: A sound wve hs wvelength of 20 m. Find its frequeny. Mirror d You stnd 2 feet in front of mirror. How fr wy does your imge seem? d Whih letter shows where the inoming light ry will go? Whih rrow shows the pth tken y the lens? The etween the inident ry nd refleted ry is 60 o. Wht is the of refletion? The of refletion is 40 o. Wht is the of inidene? If wve s fourth hrmoni hs frequeny of 24 Hz, wht is its nturl frequeny nd wht is the frequeny of H 6? Find its period: Wht hrmoni is this? Could humn her this frequeny? Mrk the nodes nd nti-nodes. How mny wvelengths is it? If sound wve s frequeny is 100 Hz. Wht is its period? You yell into nyon nd it tkes 3 seonds for the eho to ome k to you. How fr wy is the other side of the nyon? Find the fundmentl frequeny: 5th hrmoni frequeny: Cn we her this frequeny? 100 Hz