Experiments with milk during Go Green classes

During the last Go Green class, our students thought about how to make a milk rainbow. They found that when drops of food coloring are placed on the surface of the milk, the food coloring hangs in a small area of it. When we touch the milk with a cotton swab soaked in soap, the colors will spread over it, creating fancy swirls. This is because soap reduces the surface tension of the milk and reacts with the fat in it. Thanks to this, we can observe colorful patterns, and the experiment is so simple that it can be easily done even at home.