If you spent your childhood listening to well-meaning adults chastise you for cracking your knuckles—“You’ll get arthritis!”—you’re not alone. So did Donald Unger, which prompted him to launch what became a 50-year-long experiment (tested only on himself) to discover if cracking his knuckles really would cause any joint damage.

On this episode of Misconceptions, Mental Floss's Justin Dodd is sharing Unger’s findings and debunking some other pervasive myths about health and wellness. Who, for example, convinced everyone that eight glasses of H2O per day was the one-size-fits-all hydration quota for humans—and does that advice actually hold water? Also, how good is vitamin C at keeping the common cold at bay (if at all)?

Hear answers to those questions and more below, and subscribe to the Mental Floss YouTube channel for future illuminating videos.