Soda Lab


To understand density.


If you look in the refrigerator, there is a solution you can easily identify - a soft drink. No matter whether it is called soda, soda pop, or just plain pop, all soft drinks basically contain the same solutes dissolved in water. These include a sweet syrup, artifcial flavoring, and carbon dioxide gas to give it a bubbly taste. Have you ever shaken a soft drink bottle or can and then quickly removed the cap? If so, you know that the soda sprayed out from the bottle as soon as you took the cap off. This is due to carbonation.

To make the soft drink, the manufacturer adds carbon dioxide gas under pressure. Bubbles form and come together. You can see these gas bubbles come to the surface of the liquid whenever you open the soft drink. The pressure, sealed in by the can, and these bubbles force the water to spray out when you break the seal. The gas is also responsible for the sparkling taste that is charcteristic of carbonated solution. If you leave the open container of soda standing for a long enough time, the drink will taste flat and have fewer bubbles because most of the carbon dioxide gas has escaped from the water.

Although all carbonated beverages contain carbon dioxide gas, one solute that may differ in various types of soft drinks is sugar. Whereas regular drinks contain sugar as the main sweetening ingredient, diet beverages use a substitute such as saccharin. Saccharin is said to be 300 times sweeter than sugar, so in using such a sugar substitute, a smaller quantity is added. By replacing sugar with saccharin, the manufacturer is reducing the number of calories in the soft drink for those who are concerned about their weight.

Since diet beverages contain less sugar, how does their density compare to that of regular soft drinks? Recall that density represents the amount of mass present in a given volume. Expressed as a formula, density is equal to mass (usually expressed in grams) divided by the volume. In the following experiments, first you will examine the amount of sugar in many soft drinks. Then you will compare the densities in regular and diet soft drinks.

Procedure I: Determining the Amount of Sugar in Soft Drinks

This procedure was created by the Women in Science program at Appalachian State University

Procedure II: Density of Diet vs. Regular Soft Drinks

This procedure was submitted by the Summer Institute at Durham Academy

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