Spectronomy Lab

In this lab, we learned about diffraction of light, and how to use this to find the spectral lines and eventually the compositions of various elemental gasses. 

Part I: Observing Spectra Using a Diffraction Grating

A. First, we observed visible light with a diffraction grating. We were able to see the spreading of the colors of light, which would be considered a continuous spectrum. "A grating uses the wave phenomena of diffraction and interference to produce spectra."
B. For the rest of the lab, we used a spectrometer, which labels the spectra of light on a scale. On this scale are wavelength values in nanometers (nm), which are numbered 400-700 nm. 

Part II: Observing the Continuous Spectrum of an Incandescent Light Bulb

A. First, we calibrated our spectrometers by looking at an incandescent light bulb. Through this, we were able to see the continuous spectrum fall on the wavelength scale. This is what one would have seen while viewing an incandescent light bulb through a spectrometer:

B. There were certain limits at which our eyes could no longer see the color on the emission spectra. For me, these were from 400 nm to 610 nm.

Part III: Observing the Emission Spectra of Several Elements

A. In this section, we looked at many different spectrum tubes, each with a different colored gas. The tubes were heated, so that there was a current flowing through it, making the gasses look luminescent. Because each gas created spectral lines, we were able to find the name of each gas simple from the color and numbers at which the spectral lines fell. Here are the results of this section:

1. Light Bulb, Continuous Spectrum

2. Hydrogen, Light Purple Gas

655 nm- Red

490 nm- Green

3. Neon, Red Gas

400 nm-700 nm, almost continuous but not quite

4. Krypton, Light Blue Gas

590 nm- orange

560 nm- green

5. Helium, peach gas

610 nm-orange

550 nm- green

505 nm- green

450 nm- blue

6. Sodium, orange gas

605 nm- orange

7. Argon- white gas

620 nm- orange

650 nm- green

440 nm- blue

495 nm- teal

 In conclusion, after looking at different elemental gasses, I have found that we are able to find which each gas is simply by observing their emission spectra. It is also possible to find the compositions of different gasses by their emission spectra as well.