Absorption Concept

Demonstrations in Absorption

Glass oil lamp with lit flame on a small platform; two shadows visible on the wall behind -- one orange-yellow from the sodium lamp and one blue-gray from the mercury lamp. A hand holding a spatula is visible near the flame.
Safety

Opaque Sodium Flame

Demonstrates that sodium vapor absorbs the same wavelengths it emits (the D-doublet at 589.0 and 589.6 nm). A salt-laden candle flame becomes opaque to sodium lamp light while remaining transparent …
Composite image: top-left shows bright yellow sodium lamp, top-right shows yellow spectral line through diffraction grating, bottom-left shows faint purple glow of sodium lamp viewed through didymium glass, bottom-right shows the spectral line nearly eliminated
Safety

Didymium Absorption Spectrum

Didymium glass absorbs the yellow sodium D-lines, dramatically dimming a sodium lamp from bright yellow to a faint purple glow. With white light, the glass removes green and yellow bands …