Episode:  MythBusters Revisited II

Original Air Date: October 12, 2005

Myths:

In this episode, the MythBusters revisit tests that received outpourings of comments / criticisms by viewers for being incorrect or having 'missed something' in the testing methodology. The tests revisited are: Plywood Builder; Exploding Gas Tank; Exploding Cola; Air conditioning; Walking / running in the rain; Blown Away


Revisit #1: Blown Away



The Myth: Can being shot really throw you backwards



Initial Results: Busted

What the Critics Said: Because the pig and Buster was hung by a hook their center of gravity was not like a persons; they should have been supported around their chest.



Experts:



Brian Feige - Gun Expert and Owner of the 50 Cal



Memorable Moments/Quotes:

-  Kari - "I would say that this is Busted, Busted, Rebusted and Busted."

 

Setup:



Tory and Grant recycle the first Pig-rig but change the support mechanism so that he is supported at his chest, making the center of gravity the same as it would be in a human.



They test the rig by throwing a baseball at Buster's chest; he falls off proving that the rig works. Kari makes a bulletproof plate for Buster in order to capture all of the bullet's energy.

 

Test:



They bring the rig to the Alemeda County Firing Range. Buster will be shot at a range of 22 ft (the average distance for a fatal shooting).



** 12 Gauge Deer Slug at 20 Feet; knocks him off the rig, but does not make him fly back.



A second test is conducted with the 50 Cal. The .5 inch steel plate is added to Buster's chest so that the full force of the 50 Cal is transferred to Buster's center of Gravity.



** 50 Caliber at 20 Feet; knocks Buster off the rig, but did not make him fly back. The Bullet pierced the metal plate and lodged in his spine.

Result:  Busted

 

Revisit #2: Running In the Rain



The Myth: Which will make you wetter, walking or running in the rain?



Initial Results: You get wetter in the rain if you run.

What the Critics Said: Because "real" rain was not used, the test was invalid



Memorable Moments/Quotes:

- Adam (about Latex suits) "Jamie feels really sexy in these. He wears them all the time on the weekends. I've come into the shop when he doesn't know anyone's here and he's like, ya, prancing around. Amazing."

 

Setup:



Jaime and Adam wait for 'real' rain, don their latex suits with the cotton overalls & caps. The overalls and caps are weighed before hand so that they can determine how much water was absorbed.

 

Test:



They begin the initial test by walking in the rain.  However, the rain stops before they are able to complete the testing.



The test is reset with Grant and Tory; they prepare by wearing the same latex, pre-weighed overalls, and caps as Jaime and Adam had. However, in this test one will walk while the other runs at the same time so they are both exposed to the same rainfall.



The first test indicated that Tory's clothes were lighter than when he began. The rain volume was not enough to overcome the margin of error. However, the rain increases and they repeat the test. They completed a series of six different runs.



 

Result:  The runner gets less wet than the walker does. On Average, they collected 4 grams less water than the walker did.



Myth Confirmed: It is better to run than walk in the rain.



Revisit #3: Exploding Cola Cans (variation on Biscuit Bullet)



The Myth: A can of Cola will explode if left in a hot car.



Initial Results: Busted

What the Critics Said: The car experiment was wrapped too early; the cola can will explode at 140 degrees; Adam was too impatient.



Setup:



Adam agreed with the assessment of the critics but proposed a new test. What will heat up faster; a white or black car.



Test:



Two identical cars are obtained; the only difference is that one is black and the other is white.



Result:  The black car got hotter, faster and retained the heat longer.

 

Revisit #4: Plywood Builder



The Myth: A man was blown off a building holding a piece of Plywood. He was able to use the plywood like a parachute and land safely back in the building.



Initial Results: Busted

What the Critics Said: The MythBusters did not take into consideration "updraft". In addition, viewers did not believe that the 15mph speed was sufficient.



Memorable Moments/Quotes:

- Tory, to Kari holding an athletic Supporter: "Party time. Who's putting it on?"



Setup:



Tory creates a support system for the back of the truck. He will be strapped into the support and hold a piece of plywood above his head. Grant will drive the truck to see if Tory can get any plywood lift.


They will look at the angle that provides lift and at what speed can he no longer hold onto the sheet of plywood.



Test:



In the first run, Tory needs to be able to put the board above his head and angle it. He is unable to raise the board. At 45 mph he is unable to hold on to the board.


In the second run, Tory starts with the board above his head. When it reaches 15mph, he is unable to hold on to the board.


Updrafts around tall buildings can reach up to 90mph, according to the American Society of Civil Engineers.



They reconstruct the experiment to create a brace. Tory hangs beneath it and waits for the lift. He experienced lift at 30mph but he was unable to hold on.



Result: Busted



 

Revisit #5: Explosive Decompression



The Myth: A gun shot will cause a pressurized plane to explosively decompress as portrayed in the movies.



Initial Results: Busted

What the Critics Said: Fans argued that the tests were invalid because the tests were done on the ground. In a flying plane air would rush over the bullet hole and increase the pressure difference that may be enough to rip the plane apart.



Setup:



Tory takes the DC 9 Souvenir door and builds an air-tight chamber around it. The chamber will be filled with smoke. They will put the chamber in the wind tunnel to see if the air passage causes any smoke to be sucked out of the bullet hole in the door.



Test #1:



The conduct an initial test; with the fan off, no smoke escapes; the pressure is the same inside and outside the chamber; with the fan on, the smoke is drawn out of the box. The wind speed is 4.6mph.



Test #2:



Grant increases the efficiency of the fan by adding streamlined acrylic to the rig. Kari builds a barometer to measure the difference in air pressure.  The winds speed increases to 19.1mph. The difference in pressure is .002psi



Test #3:



They leverage the jet pack to increase wind speed. At full throttle the wind speed increase to 30mph and the pressure increases to 0.02psi.



Test #4:



The rig is added to Tory's truck. The airflow is raised to 65mph the pressure to 0.05psi.



Result:  As the wind increases, so does the suction. A Bullet size hole at altitude at 500mph would only generate 1.4 psi and would not be enough for explosive decompression.

Busted



Revisit #6: Air Conditioning Efficiency



The Myth: More Fuel Efficient to Drive with your Windows down than with the AC at full blast.



Initial Results: At 55mph Air Conditioning was more efficient, however open Windows proved to be more fuel efficient at 45mph than AC at Full Blast.

New Data:



Both results were correct. As you go faster open window drag increases until you reach a point where AC is more efficient. That crossover point is 50mph.



Result: Busted



Revisit #7: Car Capers - Gas Tank Explosion



The Myth: In Hollywood, every bullet plus any given gas tanks equals an explosion or a fire.



Initial Results: Busted

What the Critics Said: "You should have used a tracer round."



Experts:



Frank Doyle Jr; Retired FBI Special Agent



Memorable Moments/Quotes:

- Jamie "Why didn't you use an RPG?"

 

Setup:



At Alameda County Bomb Range, they set up with a gas tank and a fire crew on hand. A gas tank is set up in a sandy area. Frank Doyle provided the MythBusters with .223 Caliber Tracer Rounds.

 

Test:



Jamie fires a single tracer round into the half-filled gas tank. The gas tank was hit but it did not ignite.



In the second run, Jamie fires a full clip of rounds and it did not cause the gas tank to ignite.



In the third test, all of the MythBusters fire at the gas tank with tracer rounds. After 75 gun shots, the gas tank did not explode.



In the last test them move the tank 50 feet back, Jamie fires several rounds and finally one of them ignites the tank.



 

Result:  Confirmed that tracer rounds will blow up a gas tank.