What makes the green stain on your jeans?

Uh...grass? Yes, but what makes the grass green? The answer is the biomolecule chlorophyll. It gets its name from the Greek words chloros ("green") and phyllon ("leaf").

Chlorophyll doesn't absorb green light well so materials, like leaves or our stained jeans, have a green color because green light is being reflected from it.

Not only does chlorophyll make plants green, it’s also the molecule that makes photosynthesis possible. Photosynthesis is the process that plants (and some algae and bacteria) use to capture the light energy from the sun and use it produce food. It also produces oxygen. Without chlorophyll most life on Earth (including us) wouldn’t be here.