I remember where I was on the very first Earth Day, on April 22, 1970: Standing mid-thigh in central Pennsylvania’s Buffalo Creek, ostensibly taking measurements of stream flow but instead watching the very expensive stream-flow measuring device break its cable and disappear quickly downstream. I remember this more than a half century later because our usually mild-mannered science teacher, Mr. Morris, became wildly animated as he told just how expensive the device, which he’d borrowed, was.