Quincy is conducting an experiment with limestone rock. He works with five rocks and begins by recording the mass of each rock. He treats each rock with a 7 milliliters of a different liquid. Quincy added these liquids to the limestone each day for a week. At the end of the week, he measured and recorded the mass of each rock.
Mass of Rock Before (grams) Mass of Rock After (grams)
Rock 1 (Distilled Water) 20 20
Rock 2 (3% acid) 20 18
Rock 3 (5% acid) 20 15
Rock 4 (10% acid) 20 10
Rock 5 (20% acid) 20 5
What is the outcome (dependent) variable in his experiment?