Speed Reads

Thanks, science!

Here's a quick way to test if your AA batteries are dead

It's pretty obvious when your alkaline batteries run out of power — the flashlight or camera or toy or whatever stops working. But what about the out-of-package batteries lying around your house? Sure, you could find or buy a battery tester. But electrical engineer Lee Hite has an easier test: Just drop your nonrecharable AA battery — or AAA, C, D, or 9 volt — on a hard surface and see if it bounces. If the alkaline battery bounces, it's dead (or near dead); if it doesn't, you're good to go. Watch Hite's video below for his explanation of why dead batteries bounce. (Hat-tip to Digg) --Peter Weber