Modern Physics > Atomic Physics > Spectra
 DCS# 7B11.65

ABSORPTION SPECTRA

light bulb viewed through diffraction grating and filter

APPARATUS

didymium glass
 202-21-G
slide projector
 202-09-F
single slit mask
 202-21-C5
diffraction grating on stand
 202-21-E5

DESCRIPTION

Use the slide projector and diffraction grating to project a white light spectrum.  Place the glass filter over part of the slit so the absorption spectrum can be compared with the continuous spectrum.

Or use the showcase bulb (202-21-B) and distribute slide-mounted diffraction gratings.

The rose-colored glass-blower's glasses filter out the sodium yellow lines and have a spectrum like that in the photo above.  The green glasses also filter out some infrared.

For a broadband absorption spectrum, use a theater gel from the Rosco swatch book, or tidy bowl, or a glow doodler.

A GE Reveal bulb has a neodymium glass envelope:  GE Reveal bulb and its spectrum

REFERENCES

Phys. Teach. 29, 454 (1991); http://dx.doi.org/10.1119/1.2343383
Phys. Teach. 48, 206 (2010); http://dx.doi.org/10.1119/1.3317466