Due to the difference in density, the can with the sugar in it sinks while the diet can floats. For a further refinement, mix in a bunch of salt--the density of the salt water increases enough that the sugared co*ke now floats.
More Detailed Explanation
- The density of a can of regular soda is just over 1 gm/cc, while that of a can ofdiet soda is just under. This makes for a dramatic display of density differences. A12-oz can of regular soda will sink in the same container of water in which the samebrand of diet soda floats. Brand is not a factor, and only in the case of 12-ozaluminum cans does the small density difference straddle the density of water. Allplastic containers sink. The reason for the behavior is the presence of 39 grams(nearly 8 teaspoons!) of sugar dissolved in the water of the regular soda. It takes amuch smaller mass of aspertaine (Nutrasweet/Equal) to flavor the diet soda. Theeffects of the air space in the can, and the mass of the can, combine with the liquiddensities to end up just over and under the density of water. This is best displayedin a transparent container of at least 4-liter capacity.
- To show that buoyancy depends on both the object and the liquid, the soda candemonstration can be taken further by adding salt to the water in which the cans havebeen placed. The dissolved salt raises the density of the water (ref. swimming in theGreat Salt Lake). When enough salt has dissolved, the sunken regular soda can willrise to the top of the water. At the same time, the floating can of diet soda willrise high enough to tip over and float on its side. It takes about 13-oz of salt (halfa standard cylindrical cardboard container) in a little more than 3 liters of water tobring about the change. The water can be pre-warmed to hasten solution of the salt,but even with regular tap water the change happens in less that twenty seconds with alittle stirring. (To quiet skeptics it might be worth stirring the water before addingsalt to prove that stirring alone does not raise the can.)
- The Dick and Rae Physics Demo Notebook, 1993; demonstration F-110
- The Physics Teacher 24, 164 (1986); Diet 7-Up, Pepsi, Slice
As an enthusiast with a deep understanding of the concepts involved, I can confidently affirm the principles behind the phenomenon described in the article. The behavior of the soda cans in water, influenced by their density and the addition of salt, can be attributed to fundamental principles of physics and fluid dynamics.
Let's break down the key concepts used in the article:
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Density Difference: The article explains that a can of regular soda has a density just over 1 gm/cc, while a can of diet soda has a density just under 1 gm/cc. This density difference is crucial in understanding why one can sinks while the other floats. The presence of approximately 39 grams of sugar dissolved in the regular soda contributes to its higher density.
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Buoyancy: The buoyancy of an object in a fluid (in this case, water) depends on the relationship between the object's density and the density of the fluid. A can will float if its density is less than that of the liquid it is placed in. In contrast, it will sink if its density is greater.
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Effects of Air Space and Can Mass: The article mentions that the effects of the air space in the can and the mass of the can combine with the liquid densities. This underscores the importance of considering not only the density of the liquid but also the overall mass and volume of the object in question.
See AlsoNew Worlds -
Transparent Container and Demonstrations: The recommendation for using a transparent container of at least 4-liter capacity is to enhance the visual impact of the demonstration. This transparency allows observers to witness the behavior of the cans and the water, providing a clear illustration of the density-related phenomena.
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Adding Salt and Changing Density: By adding salt to the water, the density of the water increases. This alteration in density affects the buoyancy of the cans. The article suggests that when enough salt is dissolved, the regular soda can, which initially sank, will rise to the top of the water. Simultaneously, the diet soda can, which initially floated, will rise high enough to tip over and float on its side.
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Salt Dissolution and Speed of Change: The article notes that the process can be expedited by pre-warming the water to hasten the dissolution of salt. However, even with regular tap water, the change in buoyancy happens in less than twenty seconds with a little stirring. This emphasizes the dynamic and relatively quick nature of the density-related effects.
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References: The article cites references, such as "The Dick and Rae Physics Demo Notebook, 1993" and "The Physics Teacher 24, 164 (1986)," providing a scholarly foundation for the described principles. Additionally, specific mention is made of using Diet 7-Up, Pepsi, and Slice in the demonstrations.
In conclusion, the article skillfully combines principles of physics, fluid dynamics, and material science to offer a captivating demonstration of density-related phenomena using soda cans and saltwater. The precision in detailing the quantities and conditions for the experiment showcases a comprehensive understanding of the underlying scientific principles.
