Every material in the physical world has a resonant frequency. I'd bet that a knock on the wood with your knuckles would generate a sound of the same frequency where your conducted-audio peak is.
|Originally posted by DoyleS|
Too many science fair projects turn into a competition of the dads instead of provoking a deep interest in science for the kid. Your role is to ask him questions that help him figure out what is going on. Don't worry about the linearity of the meter. It is an instrument and it is the best one he has and it will do.