Here’s a fun trick for Thanksgiving. If you get into an argument about whether you purchased yams or sweet potatoes at the store, chop one in half before cooking and look for milky white sap bleeding off the flesh. Only sweet potatoes do that. But if you don’t see sap, that might mean you just have an old sweet potato, so don’t place large bets when doing this. More useless trivia at “Yams versus sweet potatoes“.