Spectra of Elements Lab

SPECTRA OF ELEMENTS LAB

Part I. Spectra of selected elements

Sample Spectrum R O Y G B V Hydrogen

R O Y G B V Helium

R O Y G B V Neon

R O Y G B V Argon

R O Y G B V Krypton

R O Y G B V Xenon

R O Y G B V Mercury

R O Y G B V Nitrogen Part II Fluorescent lights vs. incandescent lights

1. Look carefully through a diffraction grating at an incandescent light. Concentrate on the red and violet ends of the spectrum. Do you see more red or more violet?

Does fabric swatch 1 look blue or purple?

Does fabric swatch 2 look red or maroon?

2. Now look at a fluorescent light. Do you see more red or more violet?

Does fabric swatch 1 look blue or purple?

Does fabric swatch 2 look red or maroon?

3. Use the spectroscope to look at the fluorescent light. Although you will see all colors of light, you should also see a few brighter lines. This is the spectrum of an element used in fluorescent light bulbs. R O Y G B V

Identify which element this is by comparing this spectrum with those in the data table on the first page.

Conclusions:

1. Use your answers to Part II, questions 1 and 2, to explain why fabrics sometimes look one color in the store and a different color (or shade) when you get the clothes home.

2. Why are the atomic spectra line spectra rather than continuous spectra (i.e. only some lines rather than a full “rainbow”)?