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Will throwing hot water on an icy winshield break the glass?

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DEAR TOM AND RAY:
I HAVE A 1984 PLYMOUTH VOYAGER. TO GET THE ICE REMOVED FROM MY WINDSHIELD ON WINTER MORNINGS, I THROW HOT WATER ON IT (NOT BOILING, JUST HOT), AND TURN ON THE WIPERS. EVERYONE TELLS ME THAT ONE DAY I'M GOING TO BREAK THE GLASS. I'VE BEEN DOING IT FOR NINE YEARS AND IT HASN'T HAPPENED YET. THE ICE MELTS AWAY IN SECONDS. PLEASE SETTLE THE WAGER I HAVE ON WHETHER I CAN DAMAGE THE WINDSHIELD.
RICHARD

RAY: GEE, RICHARD, THE LAWS OF PHYSICS WOULD LEAD US TO BELIEVE THAT YOU COULD CRACK THE GLASS. WHEN GLASS IS TAKEN FROM ONE TEMPERATURE EXTREME TO THE OTHER VERY QUICKLY, IT DOES TEND TO CRACK.

TOM: WE DON'T KNOW WHY IT DOESN'T CRACK FOR YOU. PERHAPS THE TEMPERATURE OF THE WATER IS NOT HOT ENOUGH TO PUSH IT OVER THE EDGE. OR IT MAY BE DUE TO THE FACT THAT WINDSHIELDS ARE FAR MORE DURABLE THAN THE COFFEE POTS I ALWAYS CRACK IN THE SINK.

RAY: I SUGGEST YOU TRY AN EXPERIMENT, RICHARD. GET A THERMOMETER, AND NEXT WINTER, INCREASE THE TEMPERATURE OF THE WATER A FEW DEGREES EACH DAY UNTIL THE WIND?SHIELD CRACKS. WHEN YOU FIND OUT WHAT THAT CRITICAL TEMPERATURE IS, WRITE TO US AND LET US KNOW. I'M SURE AMERICA IS WAITING.

TOM: AND WHILE YOU'RE WORKING ON THE EXPERIMENT, RICHARD, BE THINKING OF A GOOD STORY FOR YOUR INSURANCE COMPANY.
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