Taste Test

My motorcycle battery needed re-charging, so I headed down to the part of town that deals with that sort of thing. I found a place quickly, but right away I found myself in a disagreement on what liquid was needed to top off the battery. I argued that distilled water was necessary, while the mechanic at the shop insisted that it needed battery acid. The mechanic seeing that we were at an impasse, opened one of the battery terminals poured some of its contents onto his finger, and then licked his finger. He then looked at me confidently and said "it's acid". Hard to argue with that...