So what exactly is happening in this video? Basically, the acid in the soda curdles the milk.
Coke, like most soft drinks, contains significant levels of phosphoric acid. When this acid comes into contact with the proteins in the milk, the phosphate molecules bond themselves to the milk’s calcium molecules, producing a heavier compound (tricalcium phosphate) which sinks to the bottom.
The remaining components of the milk and cola are lighter than the tricalcium phosphate, so they float to the top. The hydrogen from the phosphoric acid molecules is released as gas (H2).
Here’s the chemical equation for the reaction:
3Ca + 2H3PO4 —> Ca3(PO4)2 + 3H2
Some studies have suggested that the high levels of phosphoric acid in soft drinks like Coke can increase the chances of osteoporosis for people who don’t get enough calcium in their diet.
BONUS: Coke and Pepsi are used as pesticides in India because they’re not only cheaper than the real stuff, but more effective as well.