The MythBusters The MythBusters

MythBusters Episode 60: Earthquake Machine

Premier Date: August 30, 2006

Nikola Tesla invented a machine that when attached to an object and tuned to vibrate at a certain frequency, can cause an earthquake-like effect on the object it is attached to.

busted

The MythBusters built several variations of Tesla’s pneumatic "earthquake machine" using modified jackhammers, as well as a specially designed computer-controlled electromagnetic linear actuator made by Grant. Small scale tests on metal bars were mixed, with the modified tools performing poorly while the more finely-tunable actuator produced significant vibrations in the bar. A scale test with a model of Tesla’s lab and miniature motor failed to produce any noticeable result. Finally, a large scale test using an actual bridge was attempted. The MythBusters attached the resonator to the side of a large truss bridge to see whether the entire bridge would be shaken. While the resonator did match the bridge’s frequency and produce a vibration noticeable 100 ft away, it was not strong enough to be considered an earthquake. With the combination of the lack of spectacular results and Tesla’s tendency to exaggerate his accomplishments at the time of publication, the MythBusters declared the myth busted.

Placing a lava lamp on a stove will cause an explosion that could kill a person.

confirmed

All lava lamp tests produced violent reactions. The reactions differed depending on the lamp’s design. When lava lamps with safety caps exploded, they vented their contents out through the top of the lamp because of the safety cap popping off (as designed). A bottlecapped lava lamp being tested leaked due to a poor seal, and was helped to explode with a spray of cold water (through the thermal stress caused by the cooling effect of the water on the glass). The explosion lodged a piece of glass deep into a ballistics gel dummy planted near the lamp. A jumbo lava lamp exploded with enough force to pierce the dummy with numerous shards of glass. With the combination of the violent explosion, glass shrapnel in the dummy, explicit warning labels, and a recorded incident, the myth was deemed confirmed.

Placing a can of beans on a stove will cause an explosion that could kill a person.

confirmed

The cans of beans tested exploded with force proportional to the size of the can. Larger cans explode more violently than smaller cans, especially since large cans do not have a weakened pop-open top, but the build team concluded that any can of beans on a stove is potentially lethal.

Placing a can of potted meat on a stove will cause an explosion that could kill a person.

busted

Though the can of potted meat exploded rather violently, the explosion did not have enough force to be deemed lethal.

Placing a large glass jug of milk on a stove will cause an explosion that could kill a person.

plausible

The jar of milk exploded violently, though not with a large amount of force. The build team concluded that an exploding jar of milk can be lethal if a person happened to be standing over it.