The Kid Should See This

Exploding Rainbow Milk Spiral

The classic milk, food coloring, and dish soap experiment! This easy science demonstration shows how soap can send colors flying through (2% or whole) milk, and there are lots of examples on YouTube. But this version, an Exploding Colors Milk Spiral, literally puts a twist on it. The secret: A well-positioned line of caulk and a dish soap-soaked string.

The caulk forms a wall that extends halfway across the shallow dish. When the string is placed between that caulk and a row of food color dots, the colors spiral around the dish in the opposite direction. “This video is a variable time-lapse of a reaction that went on for an hour and a half,” YouTuber AutistiVision explains. “You can see when it finally ran out of soap. This was fun!”

rainbow milk
So what’s happening? From Sick Science:

The secret of the bursting colors is in the chemistry of that tiny drop of soap. Like other oils, milk fat is a non-polar molecule and that means it doesn’t dissolve in water. When soap is mixed in, however, the non-polar (hydrophobic) portion of micelles (molecular soap structures in solution) break up and collect the non-polar fat molecules.Then the polar surface of the micelle (hydrophilic) connects to a polar water molecule with the fat held inside the soap micelle. Thanks to the soap connection, literally, the non-polar fat can then be carried by the polar water. This is when the fun begins.

AutistiVision tries more caulk configurations in the video below:
milk, food coloring, and soap experiments
milk, food coloring, and soap experiments

Visually-related: Skittles candy dissolves into rainbows and the Hot and Cold Water Science Experiment.

Plus, more soap videos and more colorful liquid experiments:
Van Gogh’s Starry Night painted on dark water
Odyssey: A universe of ink, oil, soap, and glitter in macro detail
How to make an Amazing 9 Layer Density Tower
• Guinness World Record Elephant Toothpaste Reaction
• Pacific Light: Water, ink, oil, and soap form a tiny universe of color

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