Soda and Diet Soda Experiment


  • 1 can of soda
  • 1 can of diet soda
  • 1 or 2 large, clear containers (like an aquarium, or large bowls)
  • Water

What to do:

  1. Add water to the aquarium so that it can cover the soda cans.
  2. Place the cans into the water.

What’s the Science:

The diet soda and regular soda differ in the amount of solids (sugar/sugar substitute, soft drink ingredients, etc.) that are dissolved in the liquid. The amount of dissolved solids in a liquid will affect the liquid’s density. An object will become buoyant (float) when it is less dense than the liquid surrounding it. Buoyancy is simply an upward acting force caused by the fluid. Archimedes was the first person to dissect this phenomenon and stated what is now known as Archimedes’ Principle: “Any object, wholly or partially immersed in a fluid, is buoyed up by a force equal to the weight of the fluid displaced by the object.”

One packet of an artificial sweetener is approximately equal in sweetness to about three packets of sugar, and the artificial sweetener weighs less.  The regular soda has more solids (soft drink ingredients and sugar) dissolved in the liquid than the diet soda, so it is denser than the water surrounding it causing it to sink, and the diet soda has fewer solids dissolved (soft drink ingredients and artificial sweetener) so it is less dense than the water and floats.

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About the author

Carl Nelson is the Chief Scientist at Imagination Station in Toledo, Ohio. He holds a Masters Degree in Experimental Physics from Michigan State University and has been having fun exploring (exploding?) science in Science Centers for the past 20 years.


One Response to “Soda and Diet Soda Experiment”
  1. Eric says:

    Cool experiment! I noticed this when I started using Zero Water Filters. When I used a TDS meter on regular water it sank more quickly than after using the filter. After using the filter I felt the meter push up, and I was wondering why. This puts things in perceptive. Thank you!

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