TEACHING SCIENCE AT HOME   About 150 years ago, a mother in Port Huron, Michigan, took her son out of school after a teacher called the youngster “addled.” She knew the boy was bright, so she decided to teach him at home. She encouraged his questions, let him set up a lab in the basement with old bottles and wires and parts he’d collected, and gave him a primer on physics called the School Compendium of Natural and Experimental Philosophy, which was full of experiments he could perform himself. Many years later, the son told a newspaper reporter, “My mother was the making of me.” By that time, Thomas Edison was America’s most celebrated inventor and scientist. There are several lessons to be drawn from Edison’s life. One is this: physics, chemistry, and biology aren’t just for the school lab. You can learn plenty of science at home. Perhaps the single best thing you can do is simply foster your child’s wonder about the world and teach him to ask: Why is that? What are clouds made of? Where does the water in rivers go? What makes birds fly? (Young Edison asked himself that one. He once talked a playmate...