In honor of this season of Festivals of Light – Bob Kulawiec, Chemistry teacher extraordinaire, offers the following Holiday Tale – On Strontium, on Lithium, on Copper, on Barium:
Most years, during the last class period of each section of chemistry before winter break, I share “celebratory holiday pyrotechnics” with my students. The dishes contain metal salts dissolved in methanol, a highly flammable solvent. When the methanol burns, the heat of combustion promotes the metal atoms to higher energy states. When they fall back to their ground states, they emit the excess energy in the form of visible light. Since each element has its own characteristic quantized energy states, each element emits light of different wavelengths, which we perceive as different colors. The colors correspond to the classic “flame tests” used for centuries to identify elements. They are, from left to right: lithium (bright scarlet), copper (green), strontium (reddish orange) and barium (green-tinged yellow).
Happy Holidays from the Edmund Burke School Chemistry Lab!
–Bob
