Sunday, June 20, 2021

Thoughts on Miodownik's Liquid Rules: Learned a lot of science on this imaginary plane trip

I read Mark Miodownik's book, Liquid Rules: The Delightful and Dangerous Substances That Flow Through Our Lives, with great interest. This book gives practical insights into liquids, things that we constantly see in everyday life but have very subtle physics, chemistry, and biology. The book is organized around a transcontinental plane flight from London to Paris, where the author goes through various liquids that he encounters along the journey, from the engine fuel at the beginning to the soap in the washroom and adhesive in the plane's wings in the middle, and finally to the fog upon landing in San Francisco.

I particularly liked a number of the vignettes. For example, I liked how the author discussed surface tension, i.e., the difference between the forces on the liquid surface and those in the internal structure, which leads to an apparent elastic force on the surface. I liked the way this was used to explain simple things like the way towels wick away water through microfibers, but also more subtle things like the Marangoni effect and how tears form on the surface of a highly alcoholic wine glass, and finally, how surface tension forms a repulsive spring force when wind pushes against water to give rise to waves. I was also impressed with the many different chemicals that underlie liquids, such as the mixture of alkali and fat to create soap or surfactant, which then create emulsions, and the mixing of two liquids to connect them in the form of an epoxy, or a two-part glue. I also found interesting coolants, particularly CFCs and PFCs. The latter compound is fascinating in that a rat can be completely immersed in it and yet breathe liquid oxygen like a fish.

Finally, I was intrigued by the discussion of the ballpoint pen and its ink. This is an example of a non-Newtonian liquid that changes its viscosity with pressure. Here, the fluid flows faster when it is under the pressure of the ballpoint. This allows one to write upside down with the ballpoint pen and keeps the ink from dripping out of the well even though there's no top on it. It also explains why ballpoint ink doesn't leak and doesn't diffuse through paper after it's put down, unlike fountain pen ink.

Overall, I found this a very interesting book with useful tidbits on everyday life.

Liquid Rules: The Delightful and Dangerous Substances That Flow Through Our Lives : Mark Miodownik, Michael Page

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