This morning before a physics tutoring session on optics, I had a few minutes to make a spectrometer for the session.
This spectrometer acts a lot like a prism by separating the light into the colors which make it.
Any element or molecule can only give off light at certain frequencies (colors). You can figure out what element something is by comparing its spectroscopic readout to its established “fingerprint.” You may try this with fireworks, fluorescent light, or burning of pretty much anything (safety first of course).
In order to make it I cut a square hole on one side of a box (either left or right side). Then on the opposite side of that hole I cut a very narrow vertical rectangle. The thinner this rectangle the better the resolution, but the wider it is the brighter your readout will be.
Then I cut out a piece of diffraction grating and placed it onto the square hole with tape.
Viola! Its really that easy.
Here are some videos demonstrating the work:
If you are not in the mood to experiment, I placed the precise dimensions for my manifestation of the device below:
I should mention that there is a design decision when making the slit.
The thinner you make the slit the more precise your spectrometer,
but the dimmer the readout.
The wider the slit, the brighter the readout,
but each output line will be at least as wide as your slit.
I found that 2mm worked pretty well for my purposes.
Anyways, more dimensions:
These are the things I used to make it:
- Diffraction Grating*, about $9.10 (using 1cm^2 you can make over 400 spectrometers with one of these)Link:
- Any tape
- Any cardboard box
- Something sharp and pointy to craft with
*A 1000 lines per mm grating will create a spectrum wider than the 500 lines per mm grating, allowing better resolution.