# Floating water Droplets? What's the Explanation? **URL:** \ **Category:** Factual Questions\ **Created:** [April 10, 2008, 3:47pm UTC](https://boards.straightdope.com/t/floating-water-droplets-whats-the-explanation/444770 "2008-04-10T15:47:31Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![ralph124c](https://avatars.discourse-cdn.com/v4/letter/r/8797f3/32.png) [@ralph124c](https://boards.straightdope.com/u/ralph124c)\ **Post date:** [April 10, 2008, 3:47pm UTC](https://boards.straightdope.com/t/floating-water-droplets-whats-the-explanation/444770/1 "2008-04-10T15:47:31Z")
I was sitting in the car, watching the raindrops fall…and noticed that drops of water were flying over the wet surface of the hood. My question-are these droplets being repelled by an electrostatic field? I suppose the drops could pick up a negative charge, and if the water surface is also negatively charged, then the droplets would be repelled-explaining the motion I observed. Anybody know about this phenomena? ---
**Author:** ![Ale](https://avatars.discourse-cdn.com/v4/letter/a/f19dbf/32.png) [@Ale](https://boards.straightdope.com/u/Ale)\ **Post date:** [April 10, 2008, 4:22pm UTC](https://boards.straightdope.com/t/floating-water-droplets-whats-the-explanation/444770/2 "2008-04-10T16:22:00Z")
[QUOTE=ralph124c] I was sitting in the car, watching the raindrops fall..and noticed that drops of water were flying over the wet surface of the hood. My question-are these droplets being repelled by an electrostatic field? I suppose the drops could pick up a negative charge, and if the water surface is also negatively charged, then the droplets would be repelled-explaining the motion I observed. Anybody know about this phenomena? [/QUOTE] You´d need a big fricking electromagnetic field to levitate that many water droplets, I´d guess that what you´re seeing are drops bouncing off the hood. Did you see individual droplets actually levitating for some time or just a layer of droplets some distance from the surface? ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [April 10, 2008, 4:26pm UTC](https://boards.straightdope.com/t/floating-water-droplets-whats-the-explanation/444770/3 "2008-04-10T16:26:07Z")
What you were seeing are probably air bubbles that sometimes form when a raindrop hits water. However, your lack of a good description of the phenomenon makes it difficult to say. ---
**Author:** ![Pasta](https://avatars.discourse-cdn.com/v4/letter/p/ecccb3/32.png) [@Pasta](https://boards.straightdope.com/u/Pasta)\ **Post date:** [April 10, 2008, 4:39pm UTC](https://boards.straightdope.com/t/floating-water-droplets-whats-the-explanation/444770/4 "2008-04-10T16:39:37Z")
Do you mean how the water follows the airstream when the car is in motion? Or are you talking about something happening when you are stopped? ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [April 10, 2008, 4:40pm UTC](https://boards.straightdope.com/t/floating-water-droplets-whats-the-explanation/444770/5 "2008-04-10T16:40:32Z")
[QUOTE=Q.E.D.] What you were seeing are probably air bubbles that sometimes form when a raindrop hits water. However, your lack of a good description of the phenomenon makes it difficult to say. [/QUOTE] Not air bubbles. I’ve seen this many times. If you direct a stream of water into a pool of water, at just the right volume / velocity, the stream will break up when it hits the surface, and little balls of water will go skittering across the surface. Some of them can last for quite a while (seconds), before they “pop” and get absorbed into the body of water. ---
**Author:** ![Duckster](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/duckster/32/1244_2.png) [@Duckster](https://boards.straightdope.com/u/Duckster)\ **Post date:** [April 10, 2008, 4:44pm UTC](https://boards.straightdope.com/t/floating-water-droplets-whats-the-explanation/444770/6 "2008-04-10T16:44:15Z")
Water surface tension. Until that breaks the droplet remains on its own. ---
**Author:** ![Pasta](https://avatars.discourse-cdn.com/v4/letter/p/ecccb3/32.png) [@Pasta](https://boards.straightdope.com/u/Pasta)\ **Post date:** [April 10, 2008, 4:49pm UTC](https://boards.straightdope.com/t/floating-water-droplets-whats-the-explanation/444770/7 "2008-04-10T16:49:17Z")
Oh, are you just referring to beading? If so, see [surface tension](http://en.wikipedia.org/wiki/Surface_tension) ---
**Author:** ![mwbrooks](https://avatars.discourse-cdn.com/v4/letter/m/ba9def/32.png) [@mwbrooks](https://boards.straightdope.com/u/mwbrooks)\ **Post date:** [April 11, 2008, 1:48am UTC](https://boards.straightdope.com/t/floating-water-droplets-whats-the-explanation/444770/8 "2008-04-11T01:48:19Z")
[QUOTE=beowulff] I’ve seen this many times. If you direct a stream of water into a pool of water, at just the right volume / velocity, the stream will break up when it hits the surface, and little balls of water will go skittering across the surface. Some of them can last for quite a while (seconds), before they “pop” and get absorbed into the body of water. [/QUOTE] There was a really cool photo of something like this in [Science News](http://www.sciencenews.org/articles/20070728/fob7.asp) last July 28th. Unfortunately, it’s a subscriber-only link. It shows a stream of oil falling into a rotating pan of the same stuff. The stream “bounces” twice, forming a couple of arches like a sea serpent before finally slipping in past the surface tension. The paper describing it is supposed to be in _Physical Review E_. When I read the OP, though, I thought he meant the droplets were floating in air above his hood. I don’t think I’ve seen that, unless the car was moving and they were caught in laminar flow above the turbulent air?