All around us, the fruits of science labor on our behalf to provide us with convenience, comfort, safety, and entertainment. From simple machines like wheels and levers we have come to a point where we have computers and space ships. How do they work inside, and how do the same principles make up so many different machines? Brilliantly illustrating the principles behind many of the most ubiquitous machines in the modern world, David Macaulay's The Way Things Work is a classic of science for the young and old alike.
Thousands if not Millions of times every day, people put a sheet of paper into a fax machine and press some buttons only to have a duplicate sheet of paper roll out of a machine which may literally be on the other side of the planet. Not one person in a thousand is thinking about the process of "sending" that sheet of paper thousands of miles around the globe. But the Fax machines are "thinking" away, busily scanning across the sheet1 reading the page on one end and sending information on the page to the other end, where it is printed out again. Inside the box there are motors, gears, and rollers which pull the paper through; an optical scanning element capable of breaking a page up into lines and then breaking those lines up into a pattern telling us where there is a dark spot and where there is not; and a laser printer, itself a complicated device based on lasers, heaters, and static charges. A signal is produced and converted from a binary pattern of ones and zeroes into a sequence of audible tones which can be transmitted down the phone wire and converted back into digits at the other end. But first, it has to travel through the telephone company...
We start out with simple machines, and they come more or less in order (inclined plane to lever to wheel) and accompanied by charmingly illustrative illustrations, mostly featuring mammoths and cavemen who work together to achieve various goals with the assistance of machines. In the earlier portions of the book, a new machine is demonstrated (The wheel and axle begin on page 34) and then you see some things based on these machines (such as the hydroelectric turbine on page 37 and the windmill on page 38) before moving on to the next related development (say, the gear on page 40 and then the "gearbox" (or transmission) on page 44.) Just to return to my fax machine example, we get electric motors on page 301, the "coin tester" (which has an optoelectrical sensor in it) on page 323, computers on page 330, and printers on page 349 - just about everything you need to illustrate the basic principles.
The simple truth is that most of us do not ever consider what goes on inside most of the machines in our house in any kind of detail. While every interaction in the physical world comes down to a question of physics, whether Newtownian, Einsteinian, or Bohrish2 the truth is that we do not ponder those physics often, preferring to leave the issue entirely to the engineers. It's true that you can generally do this so long as you do not need to step into their shoes (for example, to make repairs) but there is an entire unseen world of fascination within our television sets and DVD players.
If you have children, you need this book. It will help them understand (and you explain!) all the common devices in your household. There will be no more answering "I don't know" to the question "How does that work?" A coffee table is another excellent excuse to purchase it; it's a big book full of amusing illustrations, and with the potential to start conversations. But ultimately, simple curiosity is sufficient justification to pick this one up regardless of your age.