Chromatography
Chromatography is the process of dividing a substance into its separate parts. For Sharpies, performing a chromatography experiment will separate the ink's pigments, allowing you to see some of the ingredients that went in to making it. The experiment can be performed by drawing a dot on a piece of paper and placing the paper in a bowl of water. The water will act as a solvent, dispersing the ink through the fibers of the paper. Different pigment particles will disperse through the fibers at different lengths, allowing you to see them all separately.
Permanence
In this experiment, you will test how permanent the Sharpie's ink is on different material types, such as aluminum, paper and cotton. Draw five large dots on separate square pieces of each material, resulting in five square pieces each of cotton, paper and aluminum with a Sharpie dot on each. Apply water, rubbing alcohol, nail polish remover, vinegar and bleach to each dot on the various materials to see which will most easily remove the Sharpie mark.
Dye
You can perform an experiment using a Sharpie and other natural dyes to see which is the longest lasting. You will need various dyeing agents, such as fruits, mustard or other sauces, and an equal number of cloth pieces to rub them on, such as an old T-shirt. Apply one dye to each piece of cloth and let the cloths sit for awhile to fully absorb the dye. Wash each fabric piece an equal number of times and let the cloths sit outside where the sun will break down the dyes further. After a number of days, you can see the results of which dye lasts the longest.
Tie Dye
Sharpie tie-dye is an excellent chemistry experiment to show the solubility of the ink. It is helpful to have different-colored Sharpies to really highlight the effects of this experiment. Simply color in a circle on a white T-shirt with various colored Sharpies and then slowly add a few drops of rubbing alcohol. The rubbing alcohol will dissolve the Sharpie ink, making it flow through the T-shirt fabric, creating a brilliant tie-dye effect.