MythBusters Episode 89: Exploding Water Heater

A water heater can explode and shoot through the roof of a house like a rocket.

confirmed

In small scale testing, the MythBusters started with a small six gallon water heater and disabled all of its safety features under the theory of poor installation or neglect. While the water heater eventually ruptured, it did not explode like a rocket. The MythBusters then upgraded to larger thirty gallon water heater which exploded with significantly greater force, sending the water heater several hundred feet into the air. In order to confirm the stated myth, the MythBusters obtained a full size fifty two gallon water heater and built a shack around it with a roof that followed standard California building codes. The water heater eventually exploded, shooting through the roof five hundred feet into the air and disintegrating the shack. In light of these results, and the fact that there is documented evidence corroborating the myth, the MythBusters deemed it confirmed.

(The MythBusters revisit this myth in Myth Evolution to see if a water heater can explode through the roof of a two-story house.)

If a person is being dragged by a horse, the friction caused by the movement will make their jeans catch on fire.

busted

Wearing full body padding and a denim shirt and jeans, Tory allowed himself to be pulled along the ground by a horse. While the movement and friction did increase the surface temperature of the jeans, it wasn’t enough to cause the jeans to combust. The Build Team then moved the experiment into the lab, where they simulated the friction caused by being dragged by a horse with a power sander. However, when they applied the jeans to the power sander, the jeans were torn apart before they could combust. The Build Team agreed that friction alone cannot make jeans catch on fire.

Shrinking jeans while wearing them in a hot bath for six hours can kill you.

busted

The theory behind this myth is that if a person wore a pair of jeans and sat in a hot bath intending to shrink them to fit, the shrinking jeans can cut off blood circulation to the legs which can cause a lethal clot or require the legs to be amputated. The Build Team experimented with a pair ballistic gel legs with tubes running through it to simulate blood vessels. They then covered the legs in jeans and put it in a hot bath for six hours, but found no change in blood flow. They then had Grant wear a pair of blue jeans and had him sit in a hot bath for six hours. During the experiment, Grant was continually monitored by a medical expert and by the end of the six hours, he was declared healthy and in no risk of death. The Build Team decided that the myth was busted, but reminded the audience that blood clots and cutting off blood circulation are very real dangers and should not be taken lightly.