Episode 129: Hurricane Windows

Air Date: November 4, 2009

During a hurricane, it is better to have windows open than closed.

busted

The MythBusters first performed a small-scale test using a box with window panels on all sides and with pneumatic valves attached to the windows. In a wind tunnel, it was judged that having all windows open was the best option, since it provided less stress on the structure of the house. For the large-scale test, the MythBusters made use of Medusa, the world’s largest portable hurricane simulator, located at University of Florida’s Hurricane Research Facility. They built a house that was small enough to accommodate Medusa’s cowling, but otherwise built to several state codes. The house withstood the winds Medusa generated (equivalent to a Category 2 hurricane) even when the windows were closed. (The windows-open test left a mess inside the house, though.) The extra pressure exerted on the house while the windows were closed was negligibly small. The Mythbusters explained that unlike their small-scale box, the surface area of a full size house’s windows are only a fraction of the building’s total surface area, minimizing the effect. In further tests, with rain and flying debris added, the house was again left standing, but the windows were broken, resulting in a mess similar to that of the windows-open test. This meant that there would still be damage in the hurricane’s aftermath, inside or out, no matter if the windows are closed or open, and it is still best to board up one’s windows before a hurricane.

A human head dipped into liquid nitrogen for five seconds can be smashed and shattered into pieces.

busted

For this test, Grant built a robot with a large hammer to simulate an object being smashed on the counter. Four heads heads were made using a mold of Kari’s bust, three made of ballistics gel, each with a skull and brain matter analog inside, and one completely made of ice. In the two control tests, the ice head shattered while the ballistics gel head (room temperature) only had its front part broken. The test for the head dipped into liquid nitrogen for five seconds showed a result seemingly in between the two control tests: parts of the head did shatter, but not completely. To achieve the results shown in the film, the third head had to be dipped in the liquid nitrogen for five minutes. The myth was technically busted at this point. But to really simulate human flesh and blood, the myth was then retested using two pig’s heads. The head dipped for only five seconds merely had its snout flattened while the one submerged for fifteen minutes did not even shatter, completely busting the myth.

(This myth is based on a scene from the film Jason X.)

A fresh Christmas tree doused with liquid nitrogen can spontaneously explode.

busted

For a control test, a Christmas tree explosion was made using a detonation cord. Then, a second Christmas tree was sprayed with liquid nitrogen. But after half a hour and with the temperature of the tree plummeting to almost −330 °F (−201.1 °C), no explosion occurred, not even after Tory shot it with buck shot bullets. The myth was busted because conifers and other kinds of cold-climate trees have air spaces outside the tree cells large enough to accommodate the expanding water as it turns into ice, preventing them from freezing and thus preventing an explosion.

6 Comments

  1. Patrick McNamara says:

    Re your item on making a boat from ice and wood. The idea was originally mooted early in WW2 as a way of making a torpedo proof aircraft carrier for the north Atlantic to operate against submarines. The idea was to have a hull so thick it could withstand a torpedo hit. Also, the hull would incorporate refrigeration piping, so it could keep frozen as it sailed along. There is a long article on it in an Australian magazine of the late 40′s. The advent of long range planes made the idea unnecessary.

  2. MSD says:

    Just watched the “Hurricane Windows” episode for the first time, and – as always – very interesting and entertaining.

    However, one question (and I have to admit I missed a few minutes): When constructing the small house to test the hurricane myth, were the structural components also scaled down? For example, were the sizes of the wall studs and roof joists adjusted? Or the thickness of the wood wall or roof paneling, and even the thickness of the glass in the windows?

    If you use the same size lumber as a “normal sized” structure, or same-thickness of glass, but it’s spanning a smaller distance or covering a smaller area, the relative strength of those components will not be reflective of a regular-sized home – they will actually be stronger for the size of the building. And “code” is based on full-sized proportions, so adhering to that would probably distort the experiment.

    But as I said, I missed a few minutes so perhaps you did.

  3. Tom says:

    i don’t know about scaling down changing the strength factor although it makes sense to me. I’ve never heard of opening windows during a hurricane that sounds ludacris to me. I’ve always heard you open your windows during a tornado to equalize the atmospheric pressure.

  4. frank says:

    the show is so cool,thanks for many hours of quality tv.i have seen trees explode.it was not that cold. the trees were populars. the sap made pops like a 22 rifle. i thouight some one was shooting. the tree was about 8 inches in around.must havew shot the tree about 2 to 3 feet striaght up and over about 5 feet.first time and last time i ever saw that happen.ive seen scars where it has ocured.it was so violent that the end of the trunk looked like a hair brush.if any one is intrested i can try to send you some shots of the tree .thanks for one of he best tv shows on the air

  5. Gariandos says:

    Tom: The whole pressure equalization thing about tornadoes is a myth as well. Tornado damage doesn’t come from the pressure inside of it, but rather just the winds themselves. Besides, the tornado would take care of that problem by simply shattering the windows.

  6. David Kempsey says:

    The whole point of the hurricane myth is that a SEALED house would be at normal air pressure and outside would be at low pressure possibly caused the house to explode or pop at least. I don’t think that the experiments replicated that scenario.

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