Fluids flowing near a surface tend to follow the shape of the surface. Using Schlieren optics, we can see this behavior. It is known as the Coanda Effect and its explanation depends on viscosity, the frictional forces between the molecules of a fluid (be it liquid or gas). The Coanda effect is the culprit behind many everyday incidents as well as more esoteric phenomena, such has levitating a ball in a stream of air.
From the Harvard Natural Sciences Lecture Demonstrations channel on YouTube, Wolfgang Rueckner demonstrates the Coanda Effect using a wine bottle, a candle, coffee mugs, a hairdryer, a basketball, and more.
This Webby award-winning video collection exists to help teachers, librarians, and families spark kid wonder and curiosity. TKSST features smarter, more meaningful content than what's usually served up by YouTube's algorithms, and amplifies the creators who make that content.
Curated, kid-friendly, independently-published. Support this mission by becoming a sustaining member today.