physics in action and yams

Today I learned that optical brighteners in laundry detergents are chemicals that stay in the fabric and absorb UV light and radiate blue light so your white clothes look whiter. It never occurred to me that laundry detergent was so high-tech, but then again, I never gave much thought to laundry detergent until it started making me sick.

In other news, yams in the US are really just different varieties of sweet potatoes. Having read the description of actual yams, it's not clear to me that I've ever seen one. I mean, have you ever seen a yam in a grocery store with rough, scaly skin? If you ever did see a real yam, and you were a brilliant chemist in the 1950's, you could be famous (in some circles) for extracting steroids (hormones) from them, leading to the development of oral contraceptives.