Waves Interference Remote Lab2 (3) (4) PDF

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Waves Interference Remote Lab 2 Interference(This‌‌‌lesson‌‌is‌designed‌‌for‌‌‌a‌‌‌student‌‌‌working‌‌remotely‌.)‌‌This‌lab‌uses‌the‌ Waves Interference ‌simulation‌from‌PhET‌Interactive‌Simulations‌at‌University‌of‌ Colorado‌Boulder,‌under‌the‌CC-BY‌4‌license. phet.colorado/sims/html/wave-interfere...

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Waves Interference Remote Lab 2 Interference (Thislessonisdesignedfora studentw  orkingremotely.) ThislabusestheWaves InterferencesimulationfromPhETInteractiveSimulationsatUniversityof ColoradoBoulder,undertheCC-BY4.0license. https://phet.colorado.edu/sims/html/wave-interference/latest/wave-interference_en.html

Note about prior learning: StudentsshouldhavecompletedWavesonaStringRemoteLab  andWaves  RemoteLab)orlessonswithsimilarlearninggoals. InterferenceRemoteLab1(orWavesIntro Learning Goals:Studentswillbeableto: A. Createaninterferencepatternwithtwosources,anddeterminethewaystochangethepattern. B. Findpointsofconstructiveanddestructiveinterferencebyeyeandbyusingthedetectors. C. Putupabarriertoseehowthewavesmovethroughoneortwoslits.Whatsortofpatterndothe slitscreate?Howcanyouchangethispattern? Develop your understanding: OpentheInterferencescreen,thenexploretomakewaterwaveswith varyingpatterns.

Explain your understanding: 1. Considerthese threepatternsofwaterwaves:

ABC a. Describethesimilaritiesanddifferencesofthe threepatternsofwaterwaves. i.

The wave patterns between pictures A and B are similar because they both have interference patterns which shows there are multiple sources. Picture C’s wave patterns does not show any wave interference. A and C also share the similarity of frequencies and this is shown from the crests and troughs of the wave. C and B do not have any other similarities other than the amplitude of the waves.

b. Experimenttomakesimilarpatterns,thenexplainhowyoucanusethesimulationto makeeach.

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i.

To replicate A I turned on both faucets to have wave interference and put the simulation frequency at the midpoint and the amplitude at the maximum, and set the two taps at a separation of 2 cm. To replicate B I used a 3 cm gap between the two faucets which were both on, the frequency was at the maximum and amplitude was also at maximum. To replicate C, I set the frequency to midpoint and amplitude to the max and the separation between the two faucets was at a minimum, however I only had one of the faucets on. (figure 1)-A (figure 2)- B, (figure 3)-C.

c. Whydothedirectionssay“similarpatterns”? i.

Similar is used because all are interference patterns and have the basic phenomenon behind all are the superposition of waves.

2. Experimenttomakewavesofdifferentinterferencepatternswithwater,sound,andlight. Useyourownwordsandcapturedimagesfromthesimulationtoshowyoucanmeet learninggoalA:“Createaninterferencepatternwithtwosources,anddeterminethewaysto changethepattern.”

i.

ii.

If there are two or more wave fronts that cross or interact with one another, interference patterns will always occur. Constructive interference occurs when waves are in phase with each other and they are added together making much larger waves, with constructive interference the amplitude of these waves is higher. On the other hand there is destructive interference which is when the waves cancel each other out. The simulation shows the different interferences with different colors for the waves. When the faucets or sources are closer together there is less interference and the lower the frequency the less interference occurs. figures 4 shows half the maximum amplitude, figure 5 shows minimum separation, and figure 6 shows maximum separation interference waves.

3. UsetheWaterLevel watertank:

tooltounderstandwhatishappeninginthe

a. Measurethedarkandlightareasofwavesmadewithonlyonefaucet.Insertascreen imagetohelpexplainyouranswer. i. When there is only one faucet on there is no interference, there is only a change in the amplitude bc of the energy of the wave transferring out. The wave is going up and down and different points as shown by the water level tool and it shows the displacement of the wave. This is seen by the light and dark areas in the simulation waves, the dark areas are lower water level and the light areas are higher water levels.

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1. b. Makewavesusingbothfaucetsandmeasurethedark,lightandfuzzyspots.Inserta screenimagetohelpexplainyouranswer. i. Both faucets being on causes wave interference. The light areas represent the crests and the dark areas represent the troughs of the wave interference. The water level tool shows the amplitude changing to a much larger scale. This is because the net resultant amplitude is much higher than when it was just one faucet on. The fuzzy parts of the waves where they meet each other, cancel out and there is no wave because its amplitude is 0.

1. c. Whatdoyouthinkconstructiveanddestructiveinterferencemeansbasedonyour measurements? i. Constructive interference is the result of two waves being in phase with each other, which aligns their crests and troughs resulting in the amplitude to be twice the size as a normal wave. Destructive interference is when two waves are mostly out of phase so the crests and troughs cancel each other out and there is almost 0 amplitude because of the net amplitude. d. Verifyyourunderstandingusingyourtextoronlinereferences.(citereferences) i. The link below is a UConn article that specifies more about constructive and deconstructive interference using visual aids. This really helped me understand how it works in relation to amplitude. ii. https://www.phys.uconn.edu/~gibson/Notes/Section5_2/Sec5_2.htm

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1. Considerthelightpatternontheright: a. Describewherethepointsofconstructiveanddestructive interferenceareintheimageontheright. i.

The fuzzy lines are points of destructive interference and the blue and black squares are representative of constructive interference.

a. Createasimilarwavepatternandusethedetectorstofindpointsof constructiveanddestructiveinterference.

i. b. Explainhowyoumadethewavesandusedthedetector.Insertanimageoftheentirescreen forevidence. i.

To recreate the waves I put the separation to 2500 nm and had the amplitude set to the maximum amount and the frequency about ¾ the way up the bar. I also set the separation a little lower. I used the detectors on the fuzzy area and the black and blue areas to show the amplitudes of each of the constructive and destructive interferences.

1. ii.

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5.Thesethreepatternsweremadewithsoundwavesbyvaryingonlyonething.

. ABC a. Whatdoyouthinkwasvaried? i.

I think the distance between the two sources was varied.

b. Testyourideabymakingsimilarpatterns. i. c. Is there more than one way to make thesethreepatternsbyvaryingonlyonething?Testyourideasandprovideevidencefor support. i.

After testing a few different methods, varying frequency would be the best thing to change in order to replicate these 3 patterns. To replicate A I just had to put the frequency setting to half. To replicate B, the frequency was set to maximum because it lowered the wavelength. For C I put the frequency to a minimum value and that was the closest I was able to get it to the picture.

1.

- this was the reproduction of B when frequency was max

d. Trytomakesimilarpatternswithlight.Describeyourobservationsandideas.

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i.

The frequency of light waves is much larger than the frequency of the south waves so with a higher frequency there are more areas of destructive interferences that occur.

1.

- this was recreating B with the frequency at the maximum.

2.

3.

-recreating A

- recreating C

6.Summarizekeyideasthatyouwanttorememberabouttherelationshipsofinterference

patternsofwater,soundandlightwaves. i. Interference can be observed with water waves and occurs when there are two or more sources that can produce these waves. When these two sources are moved further apart from each other, there are more destructive interference areas and when the sources move closer together there are less destructive interference. Destructive interference is when the two waves are out of phase so the amplitudes cancel each other out and is zero. The properties that can affect the types of waves are amplitude which changes the height of the wave. The other is frequency which is seen in the visual as dark and light areas becoming smaller. Constructive interference patterns are caused when the two waves are in phase with each other and the amplitude is added up.

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Develop your understanding: OpentheSlitsscreen,thenexploretomakewaterwaveswithvarying patterns.

Explain your understanding: 7.Howdowavesmadebyadrippingfaucetcomparetothewavesseenpassingthroughslits?You maywanttohavebothInterference andSlitsopen(oropenthefullsimulationWaves Interference), sothatyoucaneasilycomparethewavesandtheirpatterns. i. The dripping faucet onto the wave causes the frequency to stay the same throughout, it just moves up and down. When a wave is passed through the single slit, diffraction occurs. The light spreads out and after it passes through the slit, it interferes with itself. The intensity stays the same from the point where the drop was placed until the point in which it goes through the slit. If the wave passes through two slits, the intensity is highest in between the two slits and there will be light areas above and below the 2 slits and areas with diffraction across from the slits.

8.Dothesameconceptsapplywhenyoucompare the soundandlightwavesinInterference andSlitsscreens? i. Yes the results and concepts apply to both sound and light waves. Sound and slit simulator are the same because there are no interference patterns. There is the obvious shape difference though. For sound source we see that the amplitude is similar to the slit width and the detector shows the same amplitude for both simulations. Most patterns generated by the slit simulation can be almost exactly replicated by the two sound sources. 9.Summarizeyourunderstandingofwavesastheypassthroughslits.Makesureyoudemonstrate meetinglearninggoalC“Putupabarriertoseehowthewavesmovethroughoneortwoslits.What sortofpatterndotheslitscreate?Howcanyouchangethispattern?”

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i. In order to understand the motion of waves as they pass through slits, it is important to understand diffraction. Diffraction is the bending of waves around an obstacle or in this case the barrier. The wave pattern differs depending on the slit width and the wavelength of the wave. Before passing through the slit, if the wavelength is less than the slit width, the diffraction of the waves causes them to spread out as they pass through the slit. That is why we see the waves resemble a semicircle motion. If the wavelength is greater than the slit width, the waves don’t spread out a lot and so this creates a concentration of constructive interference towards the center and destructive interference elsewhere as we saw in the simulation. In other words as the slit width increases, the spread of the waves decreases and vice versa. The slit width variable is responsible for changing the pattern in one slit simulation.Increasing the slit separation does the opposite and so there are more horizontal “fuzzy lines” separating regions of constructive interference. All of these aspects can be used to change the pattern of the waves.

Screenshots figure 1, 2, 3

figure 4,5,6

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