The Coco-Cola and Milk Reaction Experiment!

Most of us love a tall healthy glass of milk or a refreshing soda but when combined, the two thirst quenching beverages are not as appealing. With this experiment we find out why the suggestion that soda steals vital nutrients from our body may be true.

Now of course as soon as we set these mini coca cola bottles in front of the kids they were excited and eager to drink it but towards the end of the project that thought began to change!

Experiment Steps:

1. Obtain a full coco cola bottle (Plastic) and remove the coca cola label around it. Slowly open the bottle and pour enough milk into it so that the liquid levels reach where the tamper ring is located (The ring underneath the cap).

2. Screw the cap back on very tightly. Gently rotate the bottle. Do not shake it.

3. Leave the bottle sitting undisturbed. The longer you wait the more distinct the results are.

So what happens you ask?? Coca cola has an acidic pH between 2.5 and 4.5, and as most of you probably know, it can be used to take tarnish off of coins and other metals, and some people even use it to de-grease car engines, but what happens when we mix Coca cola with another liquid with a normal pH like milk?

The upper three-quarters of the bottle ends up with a clear liquid in it and the bottom quarter is filled with a solid material. When the Coca cola is diluted with milk, the phosphoric acid molecules attach to the milk giving it more density causing the soda to curdle the milk into little globs. The surprising chemical change occurs throughout the bottle and that’s followed by a physical change as the curdled milk slowly falls to the bottom.

When the phosphoric acid in the soda reacts with the calcium in the milk a chemical change occurs that creates two new products: tricalcium phosphate and hydrogen.

1. Tricalcium phosphate is the precipitate that falls out of the liquid and settles on the bottom taking almost all of the caramel coloring in the soda with it.

2. The hydrogen gas bubbles to the top and fills the space under the cap along with the CO2 that used to be held in solution by the soda.

There are some studies that suggest that over time, the high levels of phosphoric acid in consuming repeated quantities of soft drinks might increase the chance of osteoporosis which leads to chronically weak, porous, and brittle bones in those who don’t get enough calcium in their diet.

This simple demonstration shows how that might just be possible, too.