Science Buddies: "Ask an Expert"

Hello,

Question about the candle carousel project. We're testing using a timer or stopwatch. We plan to begin the test with 1 candle, then 2, 3 and 4. When we count the rotations using 2 candles for example, do we need to count how many times the blade with the mark passes over both candles. Or do we only check how many times the marked passes over 1 candle throughout the trials regardless of how many are added,?

Hi - you want to count how many complete revolutions the blade makes, so you only count when it passes over one of the candles.