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Mentos and Soda Original Air Date: August 9, 2006
Episode # 57
The Myth:
The myth isn’t that Mentos and soda combine to create an eruption of foam, but rather to find out the complete story on WHY this works.
The Experts: Adam and Jamie
Memorable/Quotable Moments:
Adam: (after seeing the reaction for the first time) I think we’re gonna have to try that a whole bunch more times!
Jamie, taking a mouthful of diet soda, shoving in a few Mentos, and then spewing foam – not once, but twice!
The Action/Results:
Kari introduced the experiment to the guys with a few pictures from her photoshoot for FHM. Both Jamie and Adam had heard of the experiment, but Adam wondered exactly why it worked, and that became the basis of these experiments.
First, Adam did the original experiment – four Mentos in a two-liter bottle of diet soda. It went off as usual, and Adam was impressed! Then, Jamie decided to remove the carbon dioxide gas from the soda, to see what happened. He proved that Mentos won’t do any erupting if there isn’t any carbon dioxide to send out of the bottle. But that wasn’t the whole story. Next, the guys tried one Mentos candy in a bottle of soda water, and compared that to one candy in a bottle of diet soda. The soda water barely bubbled out, leaving the guys to wonder about reactions between the other chemicals in the bottle of soda and the candy.
Adam then tested all the chemicals in the soda and the candy to see if any of them, on their own, would cause an eruption of foam. Bingo! Aspartame, potassium benzoate, caffeine, gum Arabic, and gelatin all had an effect on the soda water. When these chemicals mix together on the nucleation sites of Mentos candies, there is a very rapid reaction, and the carbon dioxide gas is released all at once! This part of the story is BUSTED, because none of the explanations that the guys found listed all those things as factors.
Of course, that wasn’t the end of messing with Mentos and soda! Jamie and Adam next tried to make a rocket that would be propelled by this reaction. They tried several different setups, but they just couldn’t make it work. Mentos as a rocket fuel – BUSTED.
Next, in the height competition, Adam and Jamie both made nozzles that shot the foam from the reaction 23 feet straight up! When they decided to pool their resources and work together, they did even better – shooting the foam 34 feet straight up!
Finally, the guys tried to outdo the Mentos and soda experiment. They made a flaming tower of foam from methane and soapy water. Then they tried to make a smoke bomb out of saltpeter and sugar. It did smoke, but not a lot. They blew the can off a stack of chips with burning hydrogen. And they found out why dry ice shouldn’t be sold to anyone under 18, because they made a bomb out of it. However, in the end, they decided that none of these things were as great a “parlor trick” as Mentos and soda.
Postage Stamp on a Helicopter
The Myth:
Putting a stamp on the rotor of a helicopter will unbalance it enough to make the helicopter crash.
The Experts:
Paul Pan (Century Helicopters) sells the team the models they need
Sgt. Rick Hassna (Air Support Unit) flies the police helicopter for the team
Chad Kuenzinger (rotor balance specialist) measures the amount of wobble that a postage stamp can cause on a rotor
Memorable/Quotable Moments:
Tory: I say we destroy it!
Grant: This is why we can’t have anything nice!
The Action/Results:
Although the build team began this myth at the hangar for police helicopters in Oakland, they decided to start the myth off in small scale. So they got an indestructible trainer model of a helicopter, and a 1/7th scale model of the Oakland Police helicopter. Grant put them together, while Kari and Tory weighed a stamp and realized that they were talking about a tiny amount of weight.
They bolted down the police helicopter model and put the 1/7th scale stamp on it, but absolutely nothing changed. The rotors were not out of balance at all. A weight, however, that was equal to 8000 postage stamps, was enough to throw the rotors out of balance and ruin the model completely.
Then it was time for full scale. They put a stamp on the real police helicopter and Chad Kuenzinger measured the amount of difference it made in the rotor function. It was only barely detectable, so Kari and Tory decided they would test the rest of this myth the hard way. They put another stamp on the tail rotor, just to be sure, and they went on a flight over San Francisco. They had no problems at all, and so, this myth is BUSTED!
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Episode Descriptions 
