this is a fun way to introduce chemistry students to the subject of pH.
Step 1: Setting Up
each student sets up a square field of centrifuge tubes.
I would recommend a 5x5 field because filling 25 tubes is a reasonable task.
Step 2: Filling the Tubes
in a 5x5 field you would like to create 4 ships
1x fishing boat 1 tube
2x patrol boat 2 tubes
1x cruiser 3 tubes
fill these with a liquid with a pH higher than 8 ( soapy water)
that leaves 17 tubes which can be filled with highly diluted vinegar.
Step 3: Ammo
use Litmus as ammunition.
this will cause a correct guess to turn blue and an incorrect one red.
Step 4: Let the Game Begin
let the students play against each other!