The MythBusters The MythBusters

MythBusters Episode 39: Chinese Invasion Alarm

Premier Date: October 19, 2005

The ancient Chinese were able to detect an invading army tunneling beneath the ground by using a drum submerged in a shaft.


Kari was able to hear Jamie and Tory’s digging in an underground mine shaft in two of the three tests. She actually detected them better by listening to the drum compared to Grant’s use of modern geophone equipment.

The “five-second rule” is valid when it comes to food dropped on the floor.


This myth yielded a varied number of results, but in the definitive test where the only variable was time the myth was definitively busted. There was no real difference in the amount of bacteria collected from 2 seconds exposure as there was from 6 seconds exposure.

The toilet seat is the cleanest place in your house.


Adam tested this myth just out of curiosity and when the results were compared to the bacteria samples from the “five-second rule” tests, the toilet seat actually proved cleaner than all other surfaces tested.

A dog’s mouth is cleaner than a human’s.

partly confirmed

The sample collected from Adam’s mouth had much more bacterial growth than the sample collected from Lulu the dog. Jamie suggested, however, that the bacteria from the dog may be more potent.