Disclaimer: It's been a few years since Physics 101!
I can't buy the analogy about how water cracks rocks and using
Terry's hot water scraping method. Isn't it the alternate
*freezing* and thawing process that splits the rocks? Why
should putting hot/warm water over a pit on a window do any
harm? If harm be done, it has probably already happened when
the water froze in the first place (filling the crack with ice).
I can see that perhaps eventually the water I pour on might
freeze again, but in practice it blow dries as you drive and
besides it shouldn't be any worse that the water coming from
off the road or from the sky, right?
The danger I was worried about was a too fast transition from
very cold to very hot. But, since we know there is a latent
heat to melt which must be satisfied before the surface temperature
begins to rise, I've about convinced myself we're all right --
provided we stop pouring when the ice is gone or to be safe
when we're down to the last coat which should be easy to
scrape manually.
Herr Doktor Muller, help me out here!
- Dale
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