If you have ever put a bunch of different types of sodas into a cooler on a hot summer day and let the ice melt, then you may have noticed that some of the sodas floated to the top of the cooler and some rested on the bottom of the cooler. In this homeschool science project, you’ll learn why some sodas float and others sink. After finishing this homeschool science experiment, next time you’re out with friends on a hot summer day and ice melts in your cooler, you’ll be able to explain why some of your friends have to get a little wet to get the soda they want!

To get started, you’ll need a few materials:
    •    A few unopened cans of regular (full sugar) soda of different types
    •    A few unopened cans of diet soda of different types
    •    A large ink or basin you can fill with water

Once you have these materials gathered together, you’re ready to get started with the project by following these basic steps:
    •    Fill the basin or sink with water to the top.
    •    Put one can of regular soda into the basin. Be sure that when you place the can in the water, no air bubbles are trapped underneath the can.
    •    Record your observations about what happens to the can.
    •    Place one of the cans of diet soda into the basin, being sure that no air bubbles are trapped underneath the can.
    •    Record your observations about what happens to the can.

Chances are good that one of the cans sunk while the other floated. But why? Each can of soda appears to have the same size, meaning that each of the cans should have the same volume. However, just because the volume is the same doesn’t mean that the density is the same. In fact, some densities are greater than others.

By the way, you might want to download a free copy of the Homeschool Science Experiment Guide and workbook to find more great experiments

The soda that has sugar in it has a larger density than the soda without sugar in it. Because regular soda contains so much sugar, regular sodas are denser, which means that they are more likely to sink to the bottom of the basin of water. Some sodas contain up to 40 grams of sugar, increasing the density of regular soda significantly.

However, because diet sodas are made with artificial sweeteners, such as aspartame, they have fewer grams of sweetener. After all, many artificial sweeteners are far sweeter than sugar, meaning that fewer grams of artificial sweetener are needed to achieve the same sweet taste of regular soda in diet soda. In other words, regular soda is often denser than water, so the cans of regular soda sink. However, cans of diet soda tend to be less dense than water, so they tend to float.

Test the different types of regular and diet soda in order to determine which sodas float and sink. Can you find similarities and differences between different varieties?