Carbonated drinks makers, including Coca-Cola and Pepsico, have been criticized for the health risks associated with the consumption of the liquids. Apart from sugar or the artificial Aspartame sweetener, Coke and Pepsi also contain phosphoric acids which have a negative effect on, among others, teeth enamel and bone structures. To learn about the impact of acids in the drinks, students on all levels can perform a variety of tests and experiments.
PH Value Project
Determine the acidity in soft drinks, including Coke and Pepsi, by measuring their pH values. Buy a selection of common soft drinks and include milk and water. Pour a test sample of each drink into a jar. Use a digital pH measuring meter or pH paper to get the acidity value. The lower the pH value reads, the more acidity is found in the drink and the higher the health risks are for the consumer.
The phosphoric acid found in Coke and Pepsi is reputed to dissolve the calcium in bones and therefore represents a health risk). To prove the effect of the soda pop on calcium, choose an experiment involving chalk, which is high in calcium carbonate. Cut one piece of chalk into equal sized pieces and place each of the pieces in a jar. Measure an equal amount of Coke, Pepsi, water and milk and pour the liquid over the one chalk piece at a time and document the reaction with photographic evidence. Alternatively, use limestone or egg shells, which also have a high calcium content.
The acidity contained in sodas, Coke in particular, are subject to a large amount of urban legends and lore. Among the claims are that the drinks will dissolve a T-bone steak within 24 hours and a nail within 4 days. Other rumors tell about state troopers using soda to clean blood of highways, or car exteriors being ruined by spilled Pepsi or Coke. Arrange a series of easy and quick experiments to prove or disprove the claims made in the legends. Submerge a T-bone steak for a day or a nail for a week in Coke and Pepsi to see if the acid in the soda pops dissolve the material. Ask for blood at the local butchers, pour it over some concrete, and try to rinse it first with water, then with Coke and see if there is a difference in stain removal. Beg or buy some metal car pieces from the junk yard and pour soda over them to see if it affects the paint. Document your findings with photographs and written reports.
Soda Can Corrosion
Arrange for an experiment to prove the necessity of using plastic in food protection. Despite the acidity found in soda, the liquid does not seem to affect the metal containers it is contained in. To prove that the metal must be protected by an additional layer, cut a soda can in half. Scratch on half of the can with a file or nail and leave the other part as it is. Submerge both parts in soda and leave to stand for one week, continuously documenting the effect of the soda pop on the metal with photographic evidence and written reports. After seven days, the scratched soda can show signs of distress, while the unscathed can will not have any damage at all. You can add further to the experiment by also submerging plastic in soda for seven days to prove or disprove that the drinks will affect metal, but not the polymeric structure in plastic. Test other common packing materials, including paper or textiles, for their suitability as defense against acid in soda pops by submerging them in Coke and Pepsi.
- Iowa State University: Coke or Pepsi
- Harvard University: Soda Pop Increases Risk of Bone Breaks
- Coca Cola: Products and Packaging Rumors
- University of New Hampshire: What You Should Know About Soft Drinks
- National Center for Biotechnology Information: Evaluation of The Erosive Potential of Soft Drinks
- Snopes: Acid Slip
- Geology: Limestone
- Oklahoma State University: Folk Beliefs
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