I realize you're probably not dying to perch yourself at your microwave and stare aimlessly through the glass while your food cooks. But if you find yourself waiting on that popcorn to pop and you happen to watch the bag as it inflates, rest assured: You will do no harm.

Microwave ovens have been engineered not to leak anything dangerous, says Lou Bloomfleld, Ph.D., professor of physics at the University of Virginia, and author of How Everything Works.

This physics expert says the only way micro-waves can reach you is if there is serious damage to the unit or the door is open while you cook -- which is impossible really, thanks to designers who know this would be a risky oven feature. Keep in mind too that microwaves emit thermal radiation which is quite painful. If your microwave was spitting rays at you, you'd know it.

If you're not so sure about the effectiveness of your nuker, take it to a repair shop and have it screened for leakage with an FDA-certified meter.