How the World Flows

Microfluidics from Raindrops to Covid Tests

By: Albert Folch

Narrated by: Mike Cooper

How the World Flows acts like a microscope that pulls the listener into the barely noticeable, Lilliputian world of fluids at small scales—the microfluidic world—and answers the question "What is microfluidics?" in non-technical language.

Microfluidics is the field of science that studies fluids constrained to spaces that are smaller than one millimeter wide, and by extension, the engineering field which builds devices that exploit the unique properties of fluids at these scales. Author Albert Folch explores this micro science which has inspired engineers to build devices such as engines, spray cans, ballpoint pens, inkjet and 3D printers, pregnancy and Covid tests, glucometers, asthma nebulizers, kidney dialysis machines, and DNA analyzers.

This book also shows that many processes essential to life on Earth—such as the formation of raindrops, the rise of sap in plants, and the percolation of water through soil—are all microfluidic marvels. It examines how our cells breathe, feed, and fight diseases through small capillaries. Through engaging and digestible stories, Folch takes a lens to this tiny science and demonstrates how big a role microfluidics play in life as we know it.

©2025 Albert Folch (P)2025 Oxford University Press