Lab 1: CD Spectrometer
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- Опубликовано: 14 окт 2024
- MIT 6.S079 Nanomaker, Spring 2013
View the complete course: ocw.mit.edu/6-S...
Instructors: Dr. Katey Lo, Dr. Joseph Summers, Prof. Vladimir Bulovic
This video is a tutorial on how to assemble and use a spectrometer using a CD diffraction grating and cellphone camera. Sample spectra of a white LED and red laser are also shown.
License: Creative Commons BY-NC-SA
More information at ocw.mit.edu/terms
More courses at ocw.mit.edu
I made this using the instructions from this video and it works perfectly. I can point it at the sun and I can see almost all of the fraunhofer lines very well.
My niece & I made a spectroMeter following the guidance of the video. The end result is high quality for real usage and durable enough for a nine year old. Thank you! I am not sure who has had more fun with it me or her. Our questions: What does it mean when the colors are clear and bright vs soft and fuzzy? What do the thinner vs thicker color lines mean? What does it mean when more parts of the color are show vs one color (maybe be a repeat question but not sure)?
How the refracted lines look is partly due to the wavelengths of light that the light source beam is being split into. If they are fuzzy, or a full spectrum, it partly means that the chemical composition of the materials in the light source are mixed. The HeNe (Helium Neon) laser in the video shows what we can take to be a chemically pure light source so it makes a pretty discrete band of red. A typical tungsten filament light should give about a rainbow spectrum, while a LED light should have discrete bands. The angle of prism (which is built into the pattern cast when the CDs were molded) also plays a role I believe (sorry I forget the exact mathematical forumula though).
Saved my life. Son's assignment is nearly done ! :)
My niece & I made a spectroMeter following the guidance of the video.
The end result is a high quality for real usage and durable enough for a
nine year old. Thank you! I am not sure who has had more fun with it me
or her. Our questions: What does it mean when the colors are clear and
bright vs soft and fuzzy? What do the thinner vs thicker color lines
mean? What does it mean when more parts of the color are show vs one
color (maybe be a repeat question but not sure)?
footlessmichael
Brightness = Intensity(# of photons) of the light
Thickness = how big the range of the wavelenghts is i.e. a redlaser might have a wavelenght of 740nm +- a few. Which will give you a very small red line (well most likely a dot, but thats because of the shape of the lightsource, not the light itself)
A red lamp how ever will have a much wider range like 700-800nm (and very likely some other wavelengths/colors mixed in)
I'm not sure what you mean by soft and fuzzy but I guess it's either a problem with how well the light gets focused, or the light contains many different wavelengths spanning over a range of different wavelengths/colors, so you don't get distinct lines but a gradual change from one color to the next.
Most lightsources produce light consisting of different wavelenghts. A spectrometer splits this light (different wavelenghts get refracted at a different angle) into those distinct wavelenghts.
The dark space between the lines are the wavelegths the lightsource does *not* produce(or some medium between the source and the spectrometer absorbed).
There is an 8 inch discrepancy between the needed supplies and first instructions. It's 2 X 12 not 2X4 as stated initially.
well another argument to go for the metric system ;D
All day I searching how to make a specrometer and I find you...briliant. I will give you like and subcribe right now.
After watching a few of these videos I'm dying to go to MIT. So cool.
Excelente mini curso de optica básica, principios fundamentales.
There are 3 questions people need to answer by building, this. 1. Why not Abs 12 inch black tube instead? That would be superior. 2. What mental fixation is it with the transparency spacing of the razor blades? Why not just state it in millimeters, then offer the gap in several household items, like toothpicks or 2 razor blade wide, etc. As it is in video, I have no idea how to do the gap, as unfamiliar with item mentioned, and so rushed through this step, it might as well as been cut out. 3. Since no point in spending 2.5 hours and $20 in duct tape, foam core razorblades, gas, when any step is misunderstood, why isn't the properties of a recordable CD shown to the camera? No zoom on the clear acrylic track lines. Without this zoom shot, most users will just scratch their head and assume this is beyond comprehension. All, but those with blind faith the video maker isn't leaving some critical step out. This blind faith is further shaken when other mistakes are made, like the dimensions of the foam core. At very least, address all 4 of these in the video description, so viewers don't think themselves not understanding enough to attempt to build this. If enough people build it, hopefully an android app will emerge that can be calibrated, and used commonly. Applications from element identification, to circadian rhythms, to choosing leds, to interior design and architecture, to artist lighting, color matching, lighting sales, etc, etc. Limited by imagination. Less guesswork, less work, one tool.
You had me at the argument that the gap needs to be given as a measurement- I don't keep transparencies around the house. You lost me at all the other gripes-
Thank you for posting this project really interesting
is it critical to make that tube 12 inches long? will it affect on results if i'll make it shorter or longer?
i guess the answer is "yes", but which way?
Muchas gracias por el video! espero Salvar mi curso de Física con ese proyecto
Thanks you so much, I hope to save this course and pass with this project
Como le fue Nicolás? Si la salvó?
LOVE YOU MIT!!!!
this has me hungry for more.... to visit the link & look for a similar project with a vis-spectrophotometer
as the end result , one that can measure A and T of the common 10mm sample cell.
High powered lasers can destroy IC´s. So I guess that it could be a good idea to diffuse them if you want to measure or use as reference. Just a thought.
Search youtube for: laser camera damage
Do you think it is possible to use a similar equipment to identify the element composition of a metal surface?
Buy an ICP-MS and put the metal surface through it.
You have sooo cool labs!!!
Thanks from Ajmer Rajasthan India
Neat Idea but why do I have a feeling there is a MUCH easier way to assemble the spectrometer body.
There is. By using the foam core's paper outside, you can fold the foam together with the paper backing acting as the duct tape.
Why does he says the 4 pieces of foam core should be 2 inches by 4 inches, but points to pieces lying next to a ruler which are clearly at least 12 inches long? I guess they are supposed to be 2 inches by 12 inches.
How many lumens do you need to make a spectrophotometer? I want use it against subjects on internet screen not intense ligting.
Is this as good as cheap Ebay handheld spectrometers?
May I use a dvd-r instead cd-r?
Тут один умник уже так сделал. Судя по тому, что он не отличает КД от ДВД, но смог его расковырять - ничего сложного, видимо, нет.
Nope it doesn’t work with dvd´s
"Launch the phone's relevant image capture program." This needs some explaining. Turns out my built-in camera didn't do the trick. I downloaded the SpectraSnapp app for my smart phone & will try that out.
Also, all the CDs I've come across are like plastic sandwiches with the reflective layer in the middle. I had to cut the CD into sections, split them apart, and THEN peel off the reflective layer with sticky tape.
> Also, all the CDs I've come across are like plastic sandwiches with the reflective layer in the middle
That's not CDs, that's DVDs! Read wikipedia!
I've never, ever seen a CD with plastic over both sides of the reflective label... ever... ever. Because that is not how they are made.
Katey Lo
What on earth is that Matlab nonsense? Did Newton use it? Or Max Planck? I doubt it.
Please offer proper analog quantitative calibration on your website.
thank you
I will have to watch this when I have battery life. Skipping through the video, I am puzzled. they rip apart the cd, using only the clear part? I would have thought you would need the shiny stuff? Skipping through, I must be missing something.
The shiny part is only used to reflect the laser back inside a CD reader. Its the transparent coating below the shiny part that really holds the data (and hence has micron/sub-micron features that split the color components of the light)
This is amazing.
I wonder what 2 pieces of printer transparency thickness is in fraction of inch?
About 1mm. He didn't specify in the video.
nice job!
That's cool.
amazing !!!
YESSSS
Can We use our eyes?
Thank you. 😊 I liked this video.
genius!
no detector ????????????????????????
nice
como puedo ver este vídeo traducido al español
May be I can help with that
Disappointed, I thought that CD stand for circular dicroism, not for compact disk...
look up foldable mini spectrometer
Exente curso de óptica básica.
Save ducks, don't use duck tape.
Yeah sure Mack 🙄
Jesus Christ, why tf is trending failing so hard?
Exente curso de óptica básica.