Saturday, August 22, 2009
THE START OF A GREAT YEAR IN SCIENCE ONE OF MY GOALS IS TO MAKE SCIENCE AN ENRICHING, CHALLENGING AND FUN PART OF THE STUDENTS DAY. TO KICK OFF THE YEAR IN SCIENCE I DO THE MENTOS EXPERIMENT. HERE IS SOME INFORMATION ON THE MENTOS EXPERIMENT ALONG WITH SOME EXCITING PICTURES AND VIDEOS. Main article: Diet Coke and Mentos eruption A Diet Coca-Cola bottle, shortly after Mentos were dropped into it.First popularized by Steve Spangler on 9News in 2005, which resulted in Internet coverage of the incident, a Mentos mint expedites a rapid release of carbon dioxide when dropped into a carbonated liquid, such as a soft drink, because of its high surface tension. Also, the small dents in the surface of the candy provide a great site for nucleation, which is how the carbon dioxide molecules can escape so rapidly. The escaping bubbles quickly turn into a raging foam, and the pressure can build dramatically in a restricted container such as a two-liter bottle. As Jamie Hyneman and Adam Savage, special mechanical effects experts who have come to be known as "The MythBusters," explained on an episode of MythBusters (Episode 57, Season 4; "Mentos and Soda," aired on August 9, 2006), diet sodas (particularly colas due to their visible brown color) are most commonly used for the experiment. The MythBusters also found that the fruit flavored Mentos produced a smaller reaction, supporting their theory that nucleation is the largest factor in the reaction, because the wax coating blocks the pits that allow nucleation. People are often under the illusion that aspartame causes the reaction-—this is only partly true; the MythBusters have shown aspartame to be one of many reactive components and/or catalysts in both the soda and the Mentos. Diet colas are also preferred because they do not contain large amounts of sugar like regular colas. Sugar molecules help keep the carbon dioxide in solution, slowing the reaction. Artificial sweeteners in diet colas are much sweeter per molecule, and so make up a smaller proportion of the solution and allow a faster reaction; they also enhance the reaction. The resulting geyser (popularly known as a "Diet Coke and Mentos eruption") can shoot as high as 6 meters (20 ft). The unofficial record, reached in MythBusters, was over 34 feet with the use of a nozzle. On July 10, 2007, a record number Mentos-and-Diet Coke geysers, 791, were set off in Flower Mound, Texas by employees of Books Are Fun and the company's independent representatives. Guinness World Records had a representative in attendance, who confirmed the feat.  On July 15, 2007, a world record was set in Perfetti Van Melle's hometown of Breda, North Brabant, The Netherlands, in which 850 people set off Mentos-and-Diet Coke geysers at the same time. Everyone put five pieces of Mentos in the Coke at the same time producing geysers of four to five meters high. The record will be included in the Guinness World Records. On April 23, 2008, students in the Belgian city of Leuven set a new world record, simultaneously launching 1,360 Mentos geysers. Besides making geysers with cola and Mentos, the bottles can also be fired as rockets by unscrewing the lid until a thin stream shoots and slamming horizontally into the ground, creating enough pressure on impact to blast the lid off and launch the bottle in the opposite direction. These work best when the bottle is shaken for about 20 seconds vigorously after quickly putting in the Mentos. It takes a few practices to work out how much to twist the lid off (usually approximately one full turn) but can travel large distances with this technique, often up to 20ft high and between 40–70ft horizontally. In November, 2006, the Urban Legends Reference Pages examined the rumors of people dying from eating Mentos and drinking cola. Their research found that while eating Mentos and drinking cola can result in people regurgitating the foamy result (as evidenced by numerous online videos), no actual news accounts exist of anyone dying from it. MythBusters also tested this hypothesis using sheep parts and found that the act of drinking the cola releases enough of the carbonation to prevent the violent reaction caused when the Mentos is added to the cola directly.