"Nature abhors a vacuum"

Could someone please explain the saying “Nature abhors a vacuum” to me?

I believe there’s a tendency for fluids to flow from areas of high pressure to areas of low pressure. So if a vacuum is created somewhere (an area of near zero pressure) fluids from surrounding areas will rush in to fill up the vacuum, assuming that there is no barrier.

For example, if you evacuate a container, and then open the container, air may come rushing into it. In some sense, this “destroys” the vacuum. Thus, the saying.

Hope that helps!

Depends how you use it, as silly as it seems it sometimes just refers to the effect of air pressure. I am pretty sure the phrase developed literally.

In ecology the term describes the tendency for an ecological niche to be filled. If conditions exist favorable for plant growth something will grow there. If something grows, something will be there to eat it. A gap in the food chain will be filled.

All I can say for sure is that my cats REALLY hate my Hoover.

IIRC, the phrase dates back to ancient Greece. In the book Zero: The Biography of a Dangerous Idea, the author suggests that the concept of zero and a void were rejected by people like Pythagoras who believed that anything associated with the number zero (as a vacuum would be) was unelegant and therefore wrong.

Sorry about the vague details, my copy of the book is with a friend. If I get it back today, I’ll go into more detail.

Any more info on this?

The phrase dates back to Aristotle. Aristotelian cosmology didn’t allow for the possibility of a “void”; every part of the universe had to be filled with something; an “ether” in the case of the spaces between the planets. (Aristotle was a pretty smart guy, but a pretty lousy physicist. In fairness, his main problem was that he, like most ancient Greeks, never caught on to the idea of checking their elegant theories against reality; Aristotle can’t be entirely blamed that medieval Christian Europe wound up elevating his systems of thought to the status of Revealed Truth.) This prevented Aristotle and those who followed him from having any hope of understanding force and motion and the other things Newton eventually figured out.

Of course, if you want to get really deep about it, neither relativity theory (“curved space-time”) nor quantum mechanics (“virtual particles” and “quantum foam”) really conceptualizes the vacuum as nothing. Nonetheless, Aristotelian ideas hampered the development of physics for a long time in the Western world.

Beautiful, Buck. That’s exactly it. Charles Seife also mentions that Archimedes almost developed a form of calculus while trying to find a way to compute the area of parabolic mirrors. But without zero, and the related concept of infinity, wacky Archie never broke through.

I’d highly recommend Zero. It gives an easy reading history of how the concept of zero has been around for thousands of years yet only recently has it gained general acceptance.

Damn, I sound like I’m on “Reading Rainbow”…

This expression never really made sense to me, since more than 99.99% of everything I consider to be “nature” is a vacuum…

It’s somewhat as if the phrase “The Sun revolves around the Earth” had inexplicably entered the vernacular as some sort of proverbial expression of varied and uncertain meaning. Usually people use “NAAV” in contexts which don’t have anything to do with the original idea that was being expressed, often meaning something on the order of “if you build it, they will come”, or else expressing some jocular reference to the way their cat reacts when they clean the carpet.