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Module 1 Assignment 1
Describe the light sources and spectra that you have projected in detail as well as any experimental difficulties you encountered in the process. How do the different light sources compare with each other?
The sun displayed the full color spectrum. it was interesting using this large diffraction grating, because it showed a repeating pattern for the spectrum. Also, it appeared that the light was brightest (by far) in the yellow-green part of the spectrum. I challenge with this was that I saw "spots" for the next 20 minutes.
ReplyDeleteIt was also a challenge to find an area dark enough to view different things and not have it blended out by other light sources. i eventually settled on the garage. There, I viewed my car's headlights, brake lights, and yellow turn signal. The headlights showed a full spectrum like the sun, though not as bright. The brake lights glowed in the red through yellow part of the spectrum, and the turn signal glowed in the red through green part of the spectrum.
Just wanted to let everyone know that the kits have now been mailed to everyone who has completed the technical pre-assignment. We learned only a few weeks ago that our funding will end June 30, so we have scrambled to reschedule this class to fit within this period. That included getting more kit material!
ReplyDeleteUsing the diffraction grating, I observed a continuous spectrum for both incandescent and fluorescent lamp. The only difference between these two light sources is the presence of bright line in the spectrum of fluorescent light. After observing these light sources, I went out and observed the sunlight. I observed the same spectrum but there are some dark lines present in the spectrum.
ReplyDeleteThe only difficult part in doing this activity is the interference of other light sources. This experiment should be done in a dark room and only one light source should be present.
Sandra
I observed a rainbow spectrum when I looked on deifferent light sources: headlights, sun, incandescent bulb, fluorescent lamp.
ReplyDeleteFor the CF lamp, I saw a continous spectrum. The sharpest emmision lines for mercury are the following: blue (around 400nm) purple( around 440nm and green (around 550 nm)
For incandescent bulb: a continous spectrum similar to CF lamp spectrum
I tried the diffraction gratinsically see all the colors of the rainbow or visible light spectrum starting with the blues on the right and the reds on the left.
For sunlight: I saw a "continous spectrum" with dark lines. But these "continous" spectra are just the absorption spectra.
I observed fluorescence lamp in my room. It had continuous spectrum.
ReplyDeleteI observed projector`s light. It had very bright spectrum centered in the middle, which was thinner than the other spectra I observed.
When I looked at the neon light, there was mainly red color.
I observed smog signal light, It was not that bright, green color was seen most.
Finally I observed sun like 6pm on the way to Los Angeles. I observed dark absorption lines on sunlight spectrum. It was brighter than the others.
I started by looking on the fluorescent light in my kitchen. There is a complte rainbow or it is a continous spectrum. Then I went out to my garage and observe the spectrum of incandescent bulb. The spectrum is the same with the fluorescent lamp. I went inside and try to compare the two spectra. And I think there are bright lines present in the fluorescent spectrum. This morning I observed the spectrum of sunlight. It was also a continous spectrum but there were dark lines in the spectrum.
ReplyDeleteHow do different light source spectra vary?
ReplyDeleteComputer Screen: Defraction of the light produced lots of red and yellow, with a gap then some blue and a small amount of purple.
Halogen Light: Defraction of the light was redder than other colors, but all colors were present and no gap was seen.
Sunlight: Defraction was harder to see because the sunlight is so intense. Using the reflected light coming through the window the blue was the strongest color, but all colors were seen.
Incandescent Light: Defraction of this light most closely resembled sunlight with all the colors seen, blue and red were the most dominant.
Fluorescent Light: This light was strange… the bulb itself was repeated in each different color! All other spectra had just the separation into the colors but no distinct shape was seen). Red, green, and purple are the strongest colors.
None of the spectra observed was exactly the same as any other. The most difficult part of this was getting the sunlight as the source is too bright to look directly into.
I started by first looking at an incandescent bulb. The grating produced a smeared rainbow image of the bulb from red to violet - a continuous spectrum. When I looked at a CFL bulb I saw four distinct images of the bulb in red, green, blue and violet - apparently an emission spectrum. In this case the red and green images were brighter than the blue and violet ones.
ReplyDeleteA computer screen also demonstrates an emission spectrum at red, yellow, turquoise, blue and violet. Different than the emission spectrum from the CFL bulb.
The sun shown a continuous spectrum. I tried looking for absorption lines but no luck.
Difficulties in carrying out the assignment had to do with looking at bright light sources as the colors were washed out. Particularly the sun. I noticed that the grating also reflected a spectrum when I was looking at the sun that I could project on the sidewalk and see much more clearly.
I did my first observation using a fluorescent lamp. I notice a smooth spectrum with a bright lines just like others observed. Then I tried to observe the spectrum of incandescent bulb. This gave me a very smooth spectrum similar to fluorescent but without lines. I went out this morning and observed that the spectrum of the sun is also a contonous spectrum but with dark lines. I searched on the internet why there were dark lines and I learned that these dark lines were absorption lines. Sometimes they called these lines as Fraunhofer lines. A complete color spectrum will produce a white light just like the sun. When I looked on the red LED, its only red spectrum and maybe a blue LED will give only blue color spectrum.
ReplyDeleteI started using an incandescent bulb from my lamp shade. I noticed a complete spectrum similar to rainbow. Then I tried the CFL and I saw a similar spectrum with bright lines. The spectrum of the incandescent was smoother than the CFL. I went out to observe sunlight spectrum (from the clouds) and I saw similar spectrum. There were dark lines but you need to look closer to be able to see these dark lines. I looked on the street light and I saw also a continuous spectrum but this time there were emission lines of blue green and yellow green.
ReplyDeleteI tried this experiment in the hospital last night and since I did not bring my laptop with me I was not able to post in the blog. Anyways, here are my observations:
ReplyDeleteFluorescent light - produced a "continous spectrum. I saw a bright green line, a bright blue-purple line, and a fainter orange line. These lines tell us that the element mercury is making some of the light
Street light – continuous spectrum, with superimposed emission lines of blue, green, yellow-green. The was a fainter orange and red color and a yellow-orange absorption line
Incandescent light – produce a smooth and continuous spectrum
Neon light – mostly in the red and orange parts of the spectrum
Green LED - produced a yellowish-green. I can also see a lot of green, but also some yellow, orange, and red.
Computer monitor White neon – continuous spectrum
Sunlight - continous spectrum
This activity should be done at night
Assignment 1
ReplyDeleteSecond submission for this assignment.
I have test the incandescent light bult, cathode computer monitor, flourescent bulb and Sun and obtained the same results.
I also test red and blue light incondescent light bulbs. Both produced the entire spectrum except they produced a wider band for their respective colors. The black light incondescent bulb produced a very interesting spectrum. Between the different colors where thick black lines. Without the spectroscope, the light is purple.
I test LED light of different colors and warm white. The blue LED bulbs produce a spectrum consisting of blue and a thin band of green. The red LED produced red and a think band of yellow. The "warm" white LED bulb produced the entire spectrum but with clearly define lines.
A nice variety of experiments! I must tell those of you who reported dark lines in the solar spectrum (which at least one of you identified as the absorption Fraunhofer lines) that you didn't actually see these. With this grating the spectral resolution (you can look that up!) is much too low to see the sun's absorption lines. Could you have been looking at the dark bands between the different orders of the spectrum? (I doubt I'll see an answer due to the linear nature of this blog...:)
ReplyDeleteIncandescent light bulb produced a continuous and smooth spectrum (ROYGVB)
ReplyDeleteand fluorescent light bulbs produced a discrete spectrum. There were some bright lines and it seemed to contain less red, green and yellow than sunlight.
I went out to my garage and observed the spectrum of the headlight of my truck. It was also a continuous spectrum
The halogen lamp in my backyard produced a continuous spectrum with spectral lines. A blue LED produced a spectrum which is more on blue.
Maybe they have been looking at the dark bands between the different orders of the spectrum!!!
ReplyDeleteI started with sunlight coming through my window iluminating a 6 inch space on a white wall. When I look at the white wall through the grating, I see a just the wall where the sun is shining. Then to the left and right of the stripe I see a continuous spectrum of red, orange, yellow,white, blue, violet. I do not see any green. Then I went outside. I hid the sun behind the cardboard holder. The spectrum was a very bright, thin line that included red, orange, yellow, green, blue indigo, violet. I looked toward the sun as the light filtered through a mesquite tree and saw similar spectrum multiple times (probably reflecting off leaves).
ReplyDeleteMy bathroom lights are clear, 60 watt incandescent bulbs. The spectrum I see from these are still continuous like the sun where one color touches the next. Three colors (red, green, blue) were dominant and equal size. I could see the other colors as very thin parts of the whold spectrum.
My living room chandelier has CFL (compact fluorescent). This spectrum appeared differently. The whole outline of the bulb was repeated 4 times in 4 different colors (orange, green, blue, indigo). I got the same effect from the long fluorescent bulbs in the garage.
Lastly, I looked at my cell phone face in a dark room. It appeared to be a continuous spectrum except that it appeared white where I would expected green.
A general observation: the closer the grating was to the light source, the closer the color was to the light. As I back up from the light source, the color spectrum moves further to the sides.