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Q & A: Low-viscosity liquids floating on water

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Most recent answer: 10/22/2007
Q:
Do you know of a liquid that will float on top of water without being desolved in water while remaining at very low viscosity at low temperatures (0C or so)? Forexample oil floats without mixing with water but it gets very viscous in low temperatures. And Alcohol keeps its low viscosity in low temperatures but dissolves in water. So each one fits my requirement only half way... Thanks.
- Oguz Capan (age 57)
Marmaris, Turkey
A:
Hi Oguz,

Oils come in many different viscosities -- light machine oil or vegetable oil will have less viscosity than, say, motor oil, and some may retain their low viscosity at low temperatures. Try experimenting with various oils.

Other compounds may suit your requirements but may have other undesirable or hazardous properties. For example,

Freon -- mostly inert, but it evaporates easily, does not degrade, and harms the ozone high in the atmosphere. It also dissolves oils and fats easily and can soak through your skin. Not good to ingest! It has low viscosity at low temperatures, however. It may be difficult or impossible to obtain because of environmental regulations.

Gasoline -- very flammable! Evaproates easily, and the vapors are explosive. It's poisonous, too. Widely available.

Xylene -- this is the stuff that makes magic markers smell so bad. It is also flammable.

Turpentine -- flammable, evaporates easily, poisonous.
Used to dilute artists oil paints.

Most hydrocarbons are insoluble in water and many are liquids at room temperature with low viscosities. Unfortunatley, most are flammable or poisonous or both.

Tom

(published on 10/22/2007)

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