Cell phones . . . airbags . . . genetically modified food . . . the Internet. These are all emblems of modern life. You might ask what we would do without them. But an even more interesting question might be what would we do if we had to actually explain how they worked? The United States is riding a whirlwind of technological change. To be sure, there have been periods, such as the late 1800s, when new inventions appeared in society at a comparable...