On the "Golden Age" of children's science publishing: I'm just guessing but I think it started just after WWII and probably extended sometime into the sixties. I'm not talking so much about the little kids' Read-and-Find-Out books, although some of those are semi-classic too (like Benny's Animals And How He Put Them In Order), but something more; a collaboration between scientists, writers, and well-known (or well-known later) childrens' book illustrators. These books were written...let's say...to appeal to junior George Baileys ("Then I'm coming back here and go to college and see what they know…and then I'm going to build things"), Little Eddies, and Homer Prices. Kids like my dear Mr. Fixit who wanted to know how things worked, and who weren't scared off by having to read information instead of getting it delivered in multimedia format.
I picked up three books like this at the thrift shop last week. One is The Story of Sound, by James Geralton. (James Geralton is the pen name of Harvard physics professor emeritus Gerald Holton.) The illustrations are by Joe Krush; you might have seen Beth and Joe Krush's illustrations in The Borrowers or Gone-Away Lake. The cover is terrible, especially with the dustjacket missing; the title is boring (gee, thanks Uncle Max, just what I wanted, The Story of Sound).
But the text draws you in, keeps you interested, and teaches you something along the way. Some examples (they're not consecutive paragraphs):
Wind whistling through a forest may sound mysterious and frightening. But we can now explain that noise quite simply. When the wind hits a branch or a leaf, or a blade of grass, its smooth flow is broken up--just as the pillars of a bridge break the passing stream into small whirlpools and eddies. The eddies of water try to stay and hide right behind the pillars. The little eddies of air, too [no, not those Little Eddies], lie behind the twig or blade, leaf or telegraph wire, while the wind that rushes past pushes them lightly back and forth. The whirls of air vibrate to and fro behind their hiding place, like a flag on a stormy day that flutters from its pole. This vibration of whirling air sets up sound waves, just like any other vibration!
Hot gases, too, like the exhaust from the engine of a car, expand quite rapidly. To make one's automobile trips pleasanter a muffler is usually attached which lets the gas expand more slowly through a widening tube of metal. Thus the noise is deadened a little.
Now we have come to a large and interesting family of noises: those made by explosions! [ooh yeah]The other two books are sixties paperback reprints of earlier books: Everyday Weather and How It Works, by Herman Schneider, illustrated by Jeanne Bendick; and Research Ideas for Young Scientists, by George Barr, illustrated by John Teppich. The George Barr book in particular is terrific and asks all kinds of questions that young scientists can find answers to: How far did your helium balloon travel? What accounts for the force of a collision? How quickly can you stop your bicycle? Does a blindfolded person walk in a circle? What is the traffic picture at a busy corner? [I'm visualizing Policeman Small here...] Why are ships pointed? How reliable is your camera's shutter?
"Have you been getting poor snapshots lately, even though you used the recommended exposure? Maybe your shutter speed is not what is supposed to be....The next time you use a roll of film, save your last shot for this test. Take a record player, with an extension cord, out into the bright sunlight. Use the standard 78-rpm speed. Place a 10- or 12-inch record on the turntable. Tape a thin white paper strip to the record from the center to the edge....[take a picture while it's going around]....When the picture is printed, measure the angle with a protractor--or compare it with the one shown in the diagram...."Of course the experiments (like that one) are sometimes anachronistic; other experiments involve roller skates, milk bottles and "stapling machines" ("Dad, can I use that 'stapling machine' you have on your desk?" "Sure, Beaver"). But many of them are still workable; and some of them are more relevant than ever (How much water is wasted in your home?).
Moral: don't be scared off by boring titles or cover art showing tin-can phones; there's gold in some of them thar Golden Age books.