THE LAST WORD

摘要

I spent time in the Scottish hills last winter and on a couple of occasions I had cause to clean my glasses in a stream that originated from melting snow, effectively at 0 ℃. The water cooled the glass and its metal frame to such an extent that both lenses fell out. But how could this happen when, if I remember my school physics correctly, metal should contract more than optical glass because of a higher coefficient of expansion? Obviously this has never happened when I've been walking around under normal conditions.