Why is Pyrex rather than soda glass used in cooking glassware such as casserole dishes and saucepans?

Pyrex is preferred over soda glass for cooking glassware due to its superior thermal shock resistance. Here's why:

* Composition: Pyrex is made from borosilicate glass, which has a lower coefficient of thermal expansion than soda glass (the type used in regular windows and bottles). This means it expands and contracts less with temperature changes.

* Thermal Shock: Soda glass is more susceptible to cracking or shattering when exposed to sudden temperature changes, like going from a hot oven to a cold counter. Pyrex's lower thermal expansion allows it to withstand these changes without breaking.

Other advantages of Pyrex for cooking:

* Chemical resistance: Pyrex is resistant to most acids and chemicals, making it safe for cooking a wide range of foods.

* Durability: Pyrex is strong and durable, able to withstand repeated use and cleaning.

* Transparency: It allows you to easily monitor your cooking progress.

While soda glass is cheaper and readily available, its lack of thermal shock resistance makes it unsuitable for cookware. Pyrex's superior properties make it the preferred choice for cooking glassware.