While we're on the topic of sound I thought it would be a great time to learn how to make cup-phones. Problem is I had never really done it before. I knew we'd need cups and string, but what kind of cups? Thick string or thing string? Does the material matter? Tough questions, but lucky for me, like Thomas Edison, I've got a stable of engineers in my very own Menlo Park. Given a range of cups and strings to choose from, the kids tested out different models. By the end of the hour I expected a full report on how to make the best cup phone and time-permitting, the pros and cons of various cell-phone plans.