Did you ever have a bowl of Cheerios and notice that when there are only a few Cheerios left floating on top of the milk, they tend to cluster together in little bunches — usually around the edge of the bowl? Did you ever wonder why they do that? Well, I’ll tell you, I’ve wondered about that for many years.
If you’ve read this blog over the years, you know there are a lot of things that I wonder about. Sometimes I wonder about something for some period of time and finally I just don’t wonder about it anymore. Or, sometimes I solve the puzzlement to my satisfaction and then I stop wondering.
It turns out that I wasn’t the only one wondering about that mysterious behavior of Cheerios. Finally, the scientific community took action and performed a scientific study to explain the behavior. Thanks to Brown University for looking into this phenomenon.
Here’s what’s happening — it has to do with surface tension, the tendency of molecules on the surface of a liquid to stick together, forming a thin film across the surface — and — gravity. Small objects like Cheerios aren’t heavy enough to break the surface tension of milk, so they float. Their weight, however, does create a small dent in the surface film. When one Cheerio dent gets close enough to another, they fall into each other, merging their dents and eventually forming clusters on the milk’s surface.
That certainly puts my mind at ease. The study went on to develop a method to measure the forces that cause small object to cluster together on the surface of a liquid. I really don’t care about the forces involved — I just needed to know why they congregated.
The study did, however, name the phenomenon the “Cheerio effect.” I do like the name — now I can truly enjoy my next bowl of Cheerios….
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