I am interested in experimenting with colored flames, maybe by adding a substance to the flame. Please tell me how to do it and with what kind of substances. — M
You can produce colored flames by adding various metal salts to the burning materials. That’s what’s done in fireworks. These metal salts decompose when heated so that individual metal atoms are present in the hot flame. Thermal energy in the flame then excites those atoms so that their electrons shift among the allowed orbits or “orbitals” and this shifting can lead to the emission of particles of light or “photons”. Since the orbitals themselves vary according to which chemical element is involved, the emitted photons have specific wavelengths and colors that are characteristic of that element.
To obtain a wide variety of colors, you’ll need a wide variety of metal salts. Sodium salts, including common table salt, will give you yellow light—the same light that’s produced by sodium vapor lamps. Potassium salts yield purple, copper and barium salts yield green, strontium salts yield red, and so on. The classic way to produce a colored flame is to dip a platinum wire into a metal salt solution and to hold the wire in the flame. Since platinum is expensive, you can do the same trick with a piece of steel wire. The only problem is that the steel wire will burn eventually.