Channel your inner scientist and enjoy exploding colors with this simple rainbow milk experiment! This rainbow milk, also known as magic milk, is a classic experiment that teaches us about the chemistry of soap.
How does it work? The reason soap is so good at cleaning things is because of a special property of the soap molecules. One end of each molecule is hydrophilic, or water-loving. That end of the molecule easily dissolves in water. The other end is hydrophobic, or water-fearing. That end won't go near the water molecules, but it will attach easily to oil. That's exactly what you're seeing happen in the milk explosion. In addition to water, milk contains lots of fat and protein. Just like oil, the fat and protein molecules attach easily to soap molecules. When the soap touches the milk, it starts grabbing as many fat and protein molecules as it can. The attraction between the soap and the fat causes the molecules to move quickly, creating colorful explosions!