titration: a measured amount of a solution of unknown concentration is added to a known volume of a second solution until the reaction between them is just complete; the concentration of the unknown solution (the titer) can then be calculated
investigation: the work of inquiring into something thoroughly and systematically
ground cherry: any of numerous cosmopolitan annual or perennial herbs of the genus Physalis bearing edible fleshy berries enclosed in a bladderlike husk; some cultivated for their flowers