|
Helium Football/Catching a Bullet |
|
|
|
|
Written by Doolley012
|
|
Monday, 20 March 2006 |
Helium Football
Air Date: February 1, 2006
Episode #47
Helium Football/Catching a Bullet
The Myth: A football filled with helium will fly farther than one equally pressurized with air.
The Possible Source: A kicker who played for the Oakland Raiders from 1973 to 1986, Ray Guy, had an astonishing kick, which made the ball seem to stay in the air for exceptionally long amounts of time. This period in the air was dubbed hang time. Reportedly, during a game in the 70's, one had such a spectacular hang time that the ball was immediately collected and tested for the presence of helium. It came up negative.
The Experts:
Debrah Nolan [Statistician] provides Adam and Jamie with expert analysis of the data collected during their experiments.
Memorable/Quotable Moments:
"I put everything on my head." - Adam
"Well, yeah, but we would, you know, aspire to not be idiots." - Jamie
The Action/Results: To begin, Adam and Jamie travel to San Francisco City College where they meet with football coach John Balano and kicker Tim Sonnenburg. After getting some pointers on proper kicking techniques (and humorously attempting) the two agree that the college kicker would be the best choice for sending the ball downfield. Ten trials are performed, five with helium and five with air. The data collected shows the balls filled with helium went an average of 3 yards farther than the ones filled with air. Unfortunately, there were too many outliers in the data set, and so Adam and Jamie, unsatisfied with the method, contemplate how to achieve more accurate results.
The next experiment is simply to determine how large a difference of weight is given between the two footballs. After emptying the ball and refilling it with the standard 13psi of air, they find the ball has gained 3.2 grams in weight. The ball is once again flattened, filled with helium and weighed. Surprisingly, it is almost 7 grams lighter than the ball filled with air - even lighter than the football without anything in it. Following this, the two pressurize a football using Grant's bottle rocket rig until a satisfying explosion occurs.
To eliminate human and atmospheric variables, Adam and Jamie set up a kicking machine in an indoor hangar at Moffet Field. Jamie sets up a bungee cord to trigger the firing mechanism to further avoid human error. Jamie then proceeds to fire twenty air filled balls through the hangar, followed by twenty helium balls while Adam marks and records their distance. In the end, the Mythbusters have 60 data points and take the records to statistician Debrah Nolan. She finds that the air filled balls actually had a one-inch advantage, but declares the data inconclusive.
The two finally decide to test the transfer of energy from a kick to the ball. By modifying the A-frame shock rig used in the catching a bullet myth, Adam and Jamie can give a determined amount of force to the ball from a pendulum-like motion. After "kicking" the balls with a hammer and viewing the resultant high-speed film, they find
that both the air-filled and helium-filled balls had the same speed. The helium balls did not have the advantage.
The final conclusion was that because the helium balls were lighter, they were more susceptible to drag when flying through the air. The very thing that should've made them fly farther, was, in fact, causing the balls to move a slightly shorter distance.
Myth Busted!
Catching a Bullet In Your Teeth
Myth: Is it possible to catch a bullet in your teeth?
Experts:
Sergeant Alan Normandy [Chief Firearms Instructor at the South San Francisco Police Department] provides space and expert opinion on the experiments.
Memorable Quotes:
"I'm trying to stay in my happy place." - Kari
"Oh, this brings back memories." - Tory (while at South SFPD)
The Experiments: Tory, Kari, and Grant set up a three part experiment: First, to see whether or not teeth are able to withstand a bullet strike, second, to find if a human can react fast enough to actually catch one, and third, to make a rig that can actually catch a bullet.
To begin the first test, the team builds an A-frame which will swing a weight on a pendulum that will deliver the force into a single pin. Grant determines that the rig must swing 50 lbs from a height of four feet in order to give the same kinetic energy as a bullet would have. Meanwhile, Tory bites down on a force gauge to
determine the average human bite strength. This comes to 117 Newtons, or 85 pounds.
They use a pneumatic cylinder to clench a bullet in the dentures with this exact force.
In their first experiment, the team planned on using the incisors, which unfortunately could not withstand the strain pushing on a lead bullet, and broke before they could be tested. The team then moves the bullet back to the molars, and drop the weight.
Despite a few cracks, the teeth are intact, proving that the dentures could withstand a strike from a firearm.
To measure human reaction time, the team fire blanks in front of a high-speed camera, and see the time it takes for one of them to close their teeth down. Kari has the quickest reaction time with 9 milliseconds. This proves a human could possibly close their teeth around a moving bullet, but to be sure, they see if Kari can catch a bullet-like projectile. Tory fires several paintballs at a wall, while she attempts to catch them. Unsurprisingly, she catches none, as they are simply moving too fast.
Grant, meanwhile, begins on the third part of the experiment - building a rig that CAN catch one.
Tory is unconvinced with the first experiment, realizing that acrylic dentures are much stronger than actual teeth. Although teeth are coated with a hard layer of enamel, underneath they are a softer substance known as dentin. To retest, Tory gets a pig head and carves out the jaw from it (much to Kari's chagrin). This is then placed on the shock rig, clenching a bullet with the pneumatic cylinder.
The bullet falls out when the weight is dropped. To further emphasize the point, a live round from a .357 magnum is fired at the bullet held in the pig teeth, and the molars are blown apart. A pig's jaw, which has more integrity than a human jaw, cannot hold onto a bullet, disproving the myth completely.
The team then, with Grant's bullet-catching rig in tow, travel to the South San Francisco Police Department to shoot in the firing range while under the supervision of Chief Firearms Instructor Sergeant Alan Normandy. The rig uses a timer to trigger a pair of steel jaws to close after Grant fires the gun. Using the high-speed camera, the team fine-tunes the timing until they finally get a bullet to stop in the duck-billed shaped "mouth." Regrettably, the soft lead striking solid steel simply destroys the bullet, even with a full metal jacket. Fortunately, by observing the track marks made by the bullet, it is possible to see that they were, in fact, "catching" the bullet.
To make a final point, the team fires the gun at a set of dentures, which are demolished completely. The force is too strong for a human mouth, and on top of that, the timing of such a catch would be sheer luck.
Myth Busted!
|
|
|
Episode Descriptions 