So How Do You Weigh Things In Zero-Gravity?

With extremely controlled and strict diets, it's not like astronauts have to worry about gaining too much weight on the space station. But have you ever stopped and wondered how you would actually measure mass in a weightless environment? After all, the entire concept of weight and scales is entirely dependent on… » 7/17/12 6:40pm 7/17/12 6:40pm