Well, it's done and on the poster board. I retested everything making sure the probes were about 2.5 inches apart. When my kids did it, some of them were about .5 inches apart. The celery and mushroom were both below 1, so at least the acidic fruit was higher. We put for the conclusion that the screw was probably not strong enough to produce more than 1 volt no matter how much acid is present, and more experiments are needed. Thanks for all the help! I was really lost, esp. since I thought there were actually some alkaline pieces of produce there based on the ph strips.
