The same principal is put to use to speed
cooking in the pressure cooker. This appliance
reduces cooking times by trapping the steam
that escapes from boiling water, thereby
increasing the pressure on the liquid, and so
raising its boiling point — and maximum
temperature — to about 250ºF/120ºC. This is
the equivalent of boiling water in an open pan
at the bottom of a pit 19,000 feet/5,800 meters
below sea level.
The pressure cooker was invented by the
French physician Denis Papin in the 17th
century.
The Boiling Point Is Increased by Dissolved
Sugar and Salt When salt, sugar, or any other
water-soluble substance is added to pure
water, the boiling point of the resulting
solution becomes higher than the boiling point
of water, and the freezing point lower than
water’s freezing point. Both effects are due to
the fact that the water molecules are diluted