Texas drivers are getting some very important lessons about how to deal with their first real encounters with windscreen frost. For many Texas residents, this is their first experience dealing with a frosted windscreen. But some people are already jumping the gun — pouring boiling hot water onto their windshields — and getting a very quick lesson in thermodynamics. When your windscreen is frosted, it’s not just the outside that’s cold — the inside of the glass is too. When hot water is poured onto it, the exterior layer expands rapidly.