Everyone knows water and oil don’t mix—or at least, don’t stay mixed. Think about how you need to shake your vinaigrette salad dressing before using it every time, and how the oil separates out from the other ingredients after you let the bottle sit for a minute or two. A group of scientists from MIT have developed a new process that, defying experience, combines oil and water, and keeps them from separating. First, they created a mixture of oil and a soap-like substance called a surfactant, which can bind to both water and oil molecules. They put the mixture into a humid environment, where water vapor from the air condensed onto the surface of the oil-surfactant mix. The condensing water formed uniform, nano-sized droplets. Because the droplets are so small, once you shake up the mix, they can spread throughout the oil-surfactant mixture and remain stable for months. Researchers say the technology could be applied in pharmaceuticals, cosmetics, processed foods, and more. Watch the video above to see how it works.