Why does condensed steam form water droplets on a takeout container in neat, straight lines?
In: Physics
picture: https://twitter.com/chinamanblue/status/1205628592631242753?s=09
Water is kind of “sticky”. Unlike most liquids, water molecules love to stick to other water molecules, which is why you get droplets forming rather than an even but very thin layer. They also like to stick to any irregularities in a surface. Whenever a surface isn’t entirely smooth, water molecules go “Hey look over here, a lump!” and all the nearby water molecules follow it and they crowd around and go “ooh, weird lump!” like a group of tourists in a very, very unimpressive national park.
The reason the weird lumps are organised in lines is an artifact of the production process. A takeaway container really doesn’t need to be very high quality.
The mold that formed the plastic lid was likely machined by a cutting head that moved in one axis and then perpendicular in order to smooth the surface to the point of being imperceptible to the eye. It wasn’t perfect though and this texture was imparted to the molded plastic pieces.
When water vapor started to condense those tiny features were more likely nucleation points than elsewhere, making the pattern of droplets.
Latest Answers