# Oil and Water do mix???? **URL:** \ **Category:** Factual Questions\ **Created:** [February 24, 2001, 7:23pm UTC](https://boards.straightdope.com/t/oil-and-water-do-mix/55749 "2001-02-24T19:23:30Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![OliverTwistofLime](https://avatars.discourse-cdn.com/v4/letter/o/b487fb/32.png) [@OliverTwistofLime](https://boards.straightdope.com/u/OliverTwistofLime)\ **Post date:** [February 24, 2001, 7:23pm UTC](https://boards.straightdope.com/t/oil-and-water-do-mix/55749/1 "2001-02-24T19:23:30Z")
High enough in outer space where gravity is extremely minimal, oil and water do mix. These are the words of my friend fondly called the _astronomical nerd_. If the above is true, how does this occur? ---
**Author:** ![Ice\_Wolf](https://avatars.discourse-cdn.com/v4/letter/i/dfb087/32.png) [@Ice\_Wolf](https://boards.straightdope.com/u/Ice_Wolf)\ **Post date:** [February 24, 2001, 8:35pm UTC](https://boards.straightdope.com/t/oil-and-water-do-mix/55749/2 "2001-02-24T20:35:29Z")
In outer space, water is no longer heavier than oil, according to some sites. Therefore, it mixes. ---
**Author:** ![Squink](https://avatars.discourse-cdn.com/v4/letter/s/b5e925/32.png) [@Squink](https://boards.straightdope.com/u/Squink)\ **Post date:** [February 24, 2001, 9:10pm UTC](https://boards.straightdope.com/t/oil-and-water-do-mix/55749/3 "2001-02-24T21:10:50Z")
The hydrophobic nature of oil is unchanged by gravity, so you still get an emulsion in space. The unimportance of density differences between the two fluids will slow down the breakdown of the emulsion relative to what happens on earth, but surface tension at the water/oil interface will still drive the emulsion towards breakdown and separation of the fluids. ---
**Author:** ![Escanaba](https://avatars.discourse-cdn.com/v4/letter/e/c77e96/32.png) [@Escanaba](https://boards.straightdope.com/u/Escanaba)\ **Post date:** [February 24, 2001, 9:15pm UTC](https://boards.straightdope.com/t/oil-and-water-do-mix/55749/4 "2001-02-24T21:15:42Z")
If you shake it enough, oil and water will stay mixed. This is how “homoginized” milk is made. There are other mixtures, like mayonnaise. Even though my two examples contained additional proteins, this is not a requirement. Pure water and pure oil of any kind will work. ---
**Author:** ![Patty\_O\_Furniture](https://avatars.discourse-cdn.com/v4/letter/p/96bed5/32.png) [@Patty\_O\_Furniture](https://boards.straightdope.com/u/Patty_O_Furniture)\ **Post date:** [February 27, 2001, 2:15am UTC](https://boards.straightdope.com/t/oil-and-water-do-mix/55749/5 "2001-02-27T02:15:03Z")
From [BadChemistry.com](http://www.princeton.edu/~lehmann/BadChemistry.html#hydrophobic): > [@](#): > > …when a highly polar substance (such as water) is mixed with a nonpolar or weakly polar substance (such as most oils) the substances will separate into two phases. This phenomenon is usually rationalized in introductory chemistry text books by saying that oil is hydrophobic, and thus does not make solutions with water… > > \ > > This explanation almost universally leads students (and even some professional chemists) to believe that individual water and oil molecules repel each other, or at least attract each other very weakly. **Nothing can be further from the truth!** An individual oil molecule is attracted to a water molecule by a force that is much greater than the attraction of two oil molecules to each other. Try this at home: > [@](#): > > We can observe the consequence of this greater attraction when we put a drop of oil on a clean surface of water. Before hitting the surface, the oil will be in the shape of a spherical droplet. This is because the oil molecules are attracted to one another and a spherical shape minimizes the number of oil molecules that are not surrounded by other molecules. When the oil hits the surface of the water, it spreads out to form a thin layer. This happens because the attractions between the oil and water molecules gained by spreading over the surface is larger than the oil-oil attraction lost in making a large oil surface on top of the water. If a sufficiently small drop of oil is put on the surface, it will spread to form a single molecular layer of oil. By measuring the area produced, one can get a simple estimate for the size of each oil molecule and thus Avogadro’s number. Okay, so “mix” is the operative word here. But just make sure to note that oil most certainly **is** attracted to water, and if it weren’t for the much stronger attraction between water molecules, you would end up with a single phase mixture. I don’t see what gravity has to do with any of this. Get your friend to explain him/her/itself. ---
**Author:** ![OliverTwistofLime](https://avatars.discourse-cdn.com/v4/letter/o/b487fb/32.png) [@OliverTwistofLime](https://boards.straightdope.com/u/OliverTwistofLime)\ **Post date:** [February 27, 2001, 5:33am UTC](https://boards.straightdope.com/t/oil-and-water-do-mix/55749/6 "2001-02-27T05:33:36Z")
Attrayant and the rest of you: One of the joys of the SDMB is to read some excellent answers to a posed question. Thanks for the information.