Why do Diet Coke and Mentos React?
Jay C.

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Figure 1 (Ingredients)

Carbon Dioxide

Diet coke has CO2 (or carbon dioxide) so if you shake the bottle the CO2 comes out of the liquid and get stuck on tiny pits in the bottle called nucleation sites. Another way for CO2 to escape and that is if you drop an object in the soda the CO2 attaches to the object and if the object floats to the top the bubbles will escape. CO2 has a faintly sour taste and a sharp odor. Carbon dioxide is made by an atom of carbon and two atoms of oxygen. Carbon dioxide makes up 2 percent of the air. All life depends on dioxide. If there is more carbon than oxygen then a poisonous gas called carbon monoxide (CO) is formed. Carbon dioxide dissolves in water which also means it dissolves in soda because soda is water with flavoring. Carbon dioxide also has a solid form but it only appears when it is below -78 Celsius which is also known as dry ice.

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Figure 2 (what happens)

CO2 is a gas. Gas is a form of matter that doesn’t have a true volume or a true shape. Gas is different than solids and liquids because if you put a solid or liquid it would stay at the bottom but a gas would completely fill up the container. Gas moves faster in warmer temperatures. The more particles of gas there are the more pressure there is. Fewer particles there are the less pressure. If the gas is forced to the bottom of a liquid the pressure builds and the liquid is forced up. Gas can expand if the space increases. To compact the gases decrease the space. So when the mento dissolves all the CO2 that got stuck on the nucleation sites float to the top. But, because the liquid is above the CO2 the liquid is forced up. That is why diet coke and Mentos react.
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Figure 3 (Step by step diagram of how diet coke and Mentos react)

  • Carbon Dioxide – an invisible gas with no odor (smell)
  • Nucleation Sites – tiny cracks and imperfections
  • Gas – A type of matter that is not solid or liquid
  • Particle – A tiny amount
  • Dissolveto disintegrate or scatter
Citation list

Photosynthesis. Art. Encyclopedia Britannica. Web. 24 Sept. 2012.

Cuevas, Mapi and Sally Ann Vonderbrink Introduction to Matter Austin, TX 2007. Print

Lentech What is carbon dioxide and how is it discovered? Web. 27 September

National Geographic Society et al. The Nature of Matter Columbus, Ohio 2002. Print.

Spangler, Steve. Unforgettable experiments that make science fun. Austin, TX: Greenleaf Book Group Press, c2010. Print.