The change in heat-resistant glass has an explosive effect

Written by Theodore Gray | Published 8:58 PM, April 26, 2011

Most people may not think of Corning as a crime-fighting company, but when it sold its Pyrex brand to World Kitchen in 1998, the company accidentally made the illegal manufacture of cocaine more difficult—an unintended consequence A fascinating example of.

If you heat it too fast, ordinary glass will break: pour boiling water into an ordinary flint glass, and it may crack after a few seconds. The glass on the inside expands when it gets hot, thereby exerting pressure on the cold glass on the outside. When the pressure is too great, it will burst.

Pyrex, which was always borosilicate glass at first, solved this problem by adding boron to silica (quartz), the main component of all glasses. Boron changes the atomic structure of glass, so it remains roughly the same size regardless of temperature. Small thermal expansion means small stress. Therefore, borosilicate glass is heat resistant not because it is stronger, but because it does not need to be stronger.

When World Kitchen took over the Pyrex brand, it began to use prestressed soda lime glass instead of borosilicate to make more products. For prestressed or tempered glass, the surface is compressed by the internal force of the glass. It is stronger than borosilicate glass, but when heated, it will still expand like ordinary glass. It will not break immediately, because the expansion is only to release some internal pressure in the first place. But only one point.

One unfortunate use of Pyrex is to cook cocaine, and the container undergoes rapid temperature changes when the drug is converted from powder form to water. The pressure generated by this process exceeds the pressure that the soda-lime glass can withstand, so the entire underground industry is forced to switch from measuring cups purchased at Wal-Mart to test tubes and beakers stolen from the laboratory. This just means that if you think you know all the consequences of today’s decision, you may be wrong.

In order to eliminate prejudices in the code, MIT has developed courses to teach young people moral concepts.

Multiple experiments in a new study show that certain types of information never enter working memory.

In the next five years, the United States will spend billions of dollars on non-renewable energy.

Do you like science, technology and DIY projects?

Sign up to receive popular science emails and get highlights.

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program that aims to provide us with a way to earn money by linking to Amazon.com and affiliate sites. Registering or using this website signifies acceptance of our terms of service.