What, you don’t carry pH test strips around as a matter of routine? /s

Just call it something online, if people don’t immediately pop out of nowhere to correct you, then you’re probably right.

1. Take a sip. Did you trip balls? Acid.
2. Take a red wire, black wire, and a clock. Can you power the clock? Alkaline.

Duh.

Lick it. Just a little bit. Just a little snaky lick…

Learn botany. You can tell the approximate pH from the species of plants growing there.

1. Determine whether it’s a swamp or a marsh.

2. Tell someone else you did your part, now it’s their turn.