this is great stuff! Everytime you dare to think humanity has discovered
everything there is to know, we keep seeing the universe in new ways.
Dare I hope controlled fusion, FTL travel, and handheld laser weapons are
around the corner?
And the flying cars--where are the flying cars?!
----- Original Message -----
From: "Mr. Worf" <hellomahog...@gmail.com>
To: scifinoir2@yahoogroups.com
Sent: Monday, February 1, 2010 5:43:21 AM GMT -05:00 US/Canada Eastern
Subject: [scifinoir2] Chemistry Creates Self-Stirring Liquids
Chemistry Creates Self-Stirring Liquids
• By Laura Sanders, Science News Email Author
• January 29, 2010 |
• 5:09 pm |
• Categories: Physics
•
chemical_mixing
In a tail wagging the dog reversal, researchers have found that simple chemical
reactions can mix a solution. Usually, chemicals are stirred to enhance a
reaction, but a new study finds that the reverse is also true: Simple chemical
reactions can trigger fluid flows, reports a paper in the January 29 Physical
Review Letters.
sciencenewsThe research has implications for many chemical reactions, including
those inside stars or when carbon dioxide stored deep in the earth encounters
water, says study coauthor Anne De Wit of the Université Libre de Bruxelles in
Belgium.
De Wit and her colleagues wondered what would happen to fluid flows if the
reacting liquids were left alone and not stirred. The researchers watched a
very simple reaction — the neutralization that occurs between hydrochloric acid
and sodium hydroxide, a common chemical base — in the absence of stirring.
The researchers carefully injected the denser sodium hydroxide into a container
and then added the hydrochloric acid. The sodium hydroxide stayed on the bottom
and the hydrochloric acid sat on top. Where the two reactive chemicals met, the
reaction’s products — table salt and water — began to form. As the salty
solution formed, it crept upward and hit the lower-density acid, creating
tendrils that started to mix the solution. But the same didn’t happen below the
reaction line. This difference in how the reaction product interacted with each
of its chemical parents drove the mixing the team observed.
These asymmetrical patterns, the researchers say, distinguish mixing during a
chemical reaction from what happens when two nonreactive liquids meet, which
may look more like diffusion or other kinds of mixing.
“These kinds of beautiful patterns can be observed with very well-known
reactions,” says study coauthor Christophe Almarcha, also of the Université
Libre de Bruxelles. “This is quite fascinating for someone who’s done this
reaction hundreds of times.”
The researchers also describe reaction-driven mixing mathematically by creating
a model that predicted a pattern that looked like the real thing. The model can
be tweaked to predict patterns for other chemical reactions, which would vary
widely, Almarcha says.
“Our little model system says ‘pay attention,’” De Wit says. “If there are
reactions, then new things will happen.” For instance, if stored carbon leaches
into an aquifer and starts reacting with water, “those reactions will trigger
flows, which will enhance the mixture,” she says.
Image and Video: C. Almarcha/Université Libre de Bruxelles
See Also:
• Baffling Patterns Form in Scientific Sandbox
• Jellyfish Are the Dark Energy of the Oceans
• Top 10 Amazing Chemistry Videos
Read More
http://www.wired.com/wiredscience/2010/01/self-stirring-liquids/?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+wired%2Findex+%28Wired%3A+Index+3+%28Top+Stories+2%29%29#ixzz0eHPSDR7M
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