Liquids are a bit strange. They are formless but filling, tangible but elusive, apparently insubstantial but also incompressible. The first liquid to occur to you would probably be water, followed perhaps by oil or petrol, or other water-based substances such as beer and wine ¨C mixtures of water and another liquid, alcohol. We are extremely familiar with these liquids, yet we know little about the liquid state.

At school, you will have been told about three of the four states of matter: solid, liquid and gas. You will probably have encountered Hooke¡¯s Law describing the stiffness of solids and Boyle¡¯s Law relating the volume and pressure of a gas. But you are unlikely to have encountered any ¡°liquid laws¡±. You know that they flow under gravity to fill any shape and you can probably call Archimedes to mind ¨C for ¡°Eureka!¡± as much as for displacement ¨C but that¡¯s it. At university, you could study ¡°solid state physics¡±, but I challenge you to find a programme on ¡°liquid state physics¡± (although, to be fair, there are a few research books with that title).

It is therefore about time we had an accessible book on liquids, and Mark Miodownik has poured some of the contents of his inventive mind into this volume. He previously won the Royal Society Winton Prize for his first book Stuff Matters: The Strange Stories of the Marvellous Materials That Shape Our Man-made World (2013) and it is clear that he is passionate about stuff. Most of what we think of as ¡°stuff¡± is solid and this bleeds through into Liquid: Miodownik finds it hard to write about liquids without introducing a lot of information about solids ¨C it just gushes out of him. But enough of the puns, what about the book?

The style of?Liquid is extremely chatty and the framework is a flight from London to California; so it is clearly not a?textbook. Miodownik takes the reader on a tour of the various liquids involved in?his journey.?He begins?with kerosene, which powers the aeroplane, and then proceeds quickly via wine (from the drinks trolley), liquid crystal (in the screen on which he watches the movie), saliva and mucus (no comment), milk and coffee, air conditioning fluids, rain, magma (beneath the earth on which he eventually lands), the Queensland pitch drop experiment (I can¡¯t quite remember how he worked this in) and finally, liquid helium. Phew! In the spaces between the liquids on this journey he discusses polymers, Fukushima, rubber, Post-It notes, plywood, oil painting and a lot else.

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So what to make of all this? Liquid is a tour de force, full of interesting insights. But it has to be read rather like a novel. I was constantly engaged but occasionally irritated, for instance by reference to the artificial (and not very illuminating) device of the stranger in the adjacent seat to Miodownik, who is reading Oscar Wilde¡¯s The Picture of Dorian Gray.

Liquid?has a dramatic dust jacket that entices the reader in, but inside, the numerous monochrome illustrations are disappointing: they are too small, insufficiently clear and only rarely do they genuinely support the text. Nevertheless, Liquid is a fascinating read and a worthy contribution to helping us think about ¨C and perhaps partially understand ¨C the world around us.

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Peter Goodhew is honorary professor of Engineering at the New Model in Technology and Engineering, Hereford.

Liquid: The Delightful and Dangerous Substances That Flow Through Our Lives
By Mark Miodownik
Viking, ?16.99
ISBN 9780241977293
Published 6 September 2018