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Copyright 2002, all rights reserved
WONDER QUEST with April Holladay, A Weekly Column * June 21, 2002* Albuquerque
Salty water boils hotter
![[Corel] Sea salt](2002-06-21-sea-salt.jpg) Q: Why and how does salt affect the boiling point of water? -Delina
A: Adding salt to water raises the temperature that the water boils at. The more salt you add, the higher the
temperature. Adding 2 tablespoons of salt to 2 cups (473 milliliters) of water can raise the boiling point from
212 degrees Fahrenheit (100 degrees Celsius) by 5 degrees to 217° F (102.8° C).
[Corel] Sea salt
When water is about to boil, the water molecules near the surface bop around. Many get kicked by nearby jiggling molecules and the
extra energy careens them into the air. Of course, many air molecules right above also move around. Some of these air molecules collide
with the escaping water molecules and knock them back into the water. Water boils when enough individual surface molecules have
enough energy to zap past air molecules directly above the water surface.
Suppose we add salt to the water that's about ready to boil. Now the surface has both salt molecules and jiggling water molecules. So, a
water molecule has a smaller chance of getting kicked by a neighbor hard enough to escape because some neighbors are lethargic salt
molecules. So, fewer water molecules at the surface get past the air molecules. The water won't boil until the temperature is higher and
the water molecules on the surface are bopping around faster.
(Answered Jun. 21, 2002)
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