Video narration
How can one black ink spot turn into several colors? A coffee filter lets liquid pass through, but chromatography is not simply filtering by size. It separates by unequal travel. A mobile phase-the moving liquid or gas-carries the mixture through or across a stationary phase, the material that stays put. Components attracted more strongly to one phase are held back, so they move at different speeds. Paper chromatography and TLC use flat surfaces, with separated spots seen by position or color. Column chromatography sends liquid through packed material and collects the separated parts. Gas chromatography uses a gas to carry compounds that can be vaporized. HPLC pushes liquid through packed material at high pressure for precise measurement. Choose from a simple visible test to fast, controlled laboratory analysis. So why did black ink split? It contained several dyes, each traveling at a different speed.