In a swimming pool or lake, the water is a liquid until the water temperature gets
down to 0 C or 32. F. Water in pools
stays liquid during Las Vegas winters,
with just a bit of ice forming if it gets really cold overnight. Even when it is
chilly in January and February (usually 15° C or 60° F), water stays liquid.
Then, when our area's temperature gets really hot in the summer (usually
about 40° C or 100. F), the water in the pool is still a liquid. It would have
to be 100. C or 212. F for the water in the pool to boil! Those
temperatures have never happened on Earth.
Remember, though, that water does not have to boil to turn to a gas.
Some of the water evaporates at all temperatures. Water temperature is a
measure of the average kinetic energy of its molecules. Some molecules
have more kinetic energy than others. The molecules that have enough
kinetic energy to break the bonds with other molecules can leave the
liquid and move off into the air. That is why you have to keep filling up the
swimming pool, even though it is not boiling.
Why does water stay liquid over a large range of temperatures? Hint:
Think about molecular structure.