Diet Coke and Mentos - Mythbusters
Summary
Alike the Chemmaters article, the Mythbusters base their concept on nucleation. Nucleation being the forming of C02 bubbles as C02 particles collect in rough texture or pits of a surface in contact with the soda. The Mythbusters relate to nucleation in this reaction as they state that Mentos have tiny pits that serve as a site for nucleation when dropped in the soda. As the C02 bubbles formed by nucleation are released they rise to the mouth of the bottle and enter the atmosphere resulting in the geyser or fountain of soda.
The Mythbusters place a big emphasis on the importance of the tiny depressions in the Mentos as they are the nucleation sites. This means that at these thousands of dimples contain C02 molecules and are able to transform them into the gaseous state from which they can float up and create enough pressure to shoot the soda out the top of the bottle. The nucleation sites are able to pump out millions of bubble of C02 particles which are pulled away from the Mentos by buoyancy and float up to the top. As the massive amounts of C02 bubbles reach the top they put pressure on the soda and the surface tension, and as the surface tension ruptures the built up pressure shoots up the soda into the air. Therefore the root of this reaction is nucleation which occurs on the course surface of the Mentos.
The Mythbusters tested as to whether their theory was correct, to do so they changed the variable. The variable being the texture of the candy to detect if the eruption was caused by nucleation. By using a different type of Mentos with the same ingredients but a waxy smooth coating instead of the usual rough pitted surface, they observe that with the waxy surface the candy and soda did not result in an eruption or any significant reaction what so ever. This test proved that nucleation is the cause of the eruption as the only variable changed was the texture of the candy meaning that as the reaction only occurred with pitted Mentos, the reaction was a result of nucleation.
The Mythbusters place a big emphasis on the importance of the tiny depressions in the Mentos as they are the nucleation sites. This means that at these thousands of dimples contain C02 molecules and are able to transform them into the gaseous state from which they can float up and create enough pressure to shoot the soda out the top of the bottle. The nucleation sites are able to pump out millions of bubble of C02 particles which are pulled away from the Mentos by buoyancy and float up to the top. As the massive amounts of C02 bubbles reach the top they put pressure on the soda and the surface tension, and as the surface tension ruptures the built up pressure shoots up the soda into the air. Therefore the root of this reaction is nucleation which occurs on the course surface of the Mentos.
The Mythbusters tested as to whether their theory was correct, to do so they changed the variable. The variable being the texture of the candy to detect if the eruption was caused by nucleation. By using a different type of Mentos with the same ingredients but a waxy smooth coating instead of the usual rough pitted surface, they observe that with the waxy surface the candy and soda did not result in an eruption or any significant reaction what so ever. This test proved that nucleation is the cause of the eruption as the only variable changed was the texture of the candy meaning that as the reaction only occurred with pitted Mentos, the reaction was a result of nucleation.