My daughter is a bit of a magpie – a collector of things, some shiny, some not. If you open any small purse or pouch in her room, you’ll likely find a collection: plastic butterflies, acorns, pressed flowers, feathers, rubber bouncy balls. (I’m sure there is a fine line between her kind of “collecting” and hoarding, but for the sake of my sanity and the story, we’ll just call it collecting.)   The newest special exhibition at the Perot Museum of Nature and Science focuses on the hobby of collecting – and why people (and museums) do it.  After all, that’s what a museum does: they conserve and collect the world as we…