My son got an electricity set for Christmas that we have been playing with this afternoon. We made a simple DC circuit between a battery pack and a buzzer. I measured the voltage as 6 volts using a multimeter in parallel. We then decided to put a grape and a kiwi into the circuit. We got the following results: Grape: Lower pitch, 5.37v, 48.7 kohms (measured across the fruit) Kiwi: Higher pitch, 5.11v, 32.3 kohms I thought the pitch would be relative to the voltage, but it seems not. Given Ohms law I'm guessing pitch is relative to current? Anyone have an explanation? Thanks!

If you're measuring the voltage across the fruit then you're actually measuring voltage drop therefore the higher the voltage across the fruit, the lower the voltage at the buzzer. If you want to know what's getting to the buzzer then measure the voltage across the buzzer. Kiwi fruit has lower resistance than the grape therefore lower voltage drop which should mean higher voltage at the buzzer and higher pitch.