Spectroscopic Spectral Flame Analysis Lab
A challenging, hands-on discovery and STEM project designed for curious young minds aged 10 to 14.
Materials Needed
- • Table salt (Sodium chloride) (1 tablespoon)
- • Diet salt substitute (Potassium chloride) (1 tablespoon)
- • Borax laundry booster (Boron compound) (1 tablespoon)
- • Wooden craft splints or bamboo skewers (6 units)
- • Diffraction grating sheet or clean stripped DVD disc (1 unit)
- • Ceramic tile and safety glasses (1 set)
Pro Tips
- → Soak wooden craft splints in mineral salt solutions overnight before testing.
- → Each element produces a signature atomic emission color: Sodium = intense yellow/orange, Potassium = pale lilac/purple, Boron = bright emerald green.
- → Look at the flame through a diffraction grating (or reflection from an old DVD) to split the color into discrete spectral emission lines.
Safety First
Adult supervision strictly required for flame handling. Work on a metal tray with a water extinguisher ready.
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Step-by-Step Instructions
Step 1
Soak wooden splints in separate cups: Cup 1 = table salt (NaCl), Cup 2 = salt substitute (KCl), Cup 3 = Borax solution.
Step 2
Place a small metal dish on a heatproof ceramic tile and light a clean alcohol burner or gel flame (adult supervision).
Step 3
Hold the soaked sodium splint in the flame edge to observe characteristic bright yellow-orange light; repeat with the potassium splint to see pale lilac.
Step 4
Introduce the boron splint to observe bright emerald green, viewing the flame through a diffraction grating to identify distinct spectral lines.