I use this fun Halloween mystery to teach students about mixtures, solubility, and chromatography. Ink that dissolves in water is called “water SOLUBLE.” Water SOLUBLE black ink is a MIXTURE of several different colors of ink. If water drops fall on a message written with a water SOLUBLE black ink pen, you will find that the black ink separates into colors. The pattern of colors formed by the ink is called a chromatogram. Different brands of ink produce different chromatograms. Students will us