When Pyrex cookware first came out, it was advertised as icebox to oven. Because it was made of borosilicate glass which could weather large temperature changes without undergoing thermal shock and shattering. But today American Pyrex and Anchor Hocking dishes are made of soda lime silicate glass, which is prone to shatter. So says a report in the Bulletin of the American Ceramic Society. Researchers calculated that a rapid temperature change of just a hundred degrees Fahrenheit could fracture the new glass, compared to three hundred and thirty degrees for the old stuff. They say that means it's possible to break a glass measuring cup with boiling water. Or to explode a cool casserole dish by sliding it into a hot oven. Manufacturers say that they temper the new glass to make it stronger. And researchers did find some evidence of that. But they believed the heat treatment was inadequate. Because in the lab tests, the cookware exploded into large glass shards rather than tiny pieces as tempered auto glass does. As the saying goes, if you can't stand the heat, stay out of the kitchen. If this research is accurate, the heat is on this cookware. 

 

Thanks for the minute for scientific American sixty seconds science. I'm Christopher Intagliata.