Can air be boiled?
We are all wondering if life is possible on the frozen outer planets. Well, a visitor from a hotter planet than ours might well wonder how we managed to exist in a world where the ground is frozen solid, even on the hottest day of the year. He might shudder at the idea of our oceans, chilled to the liquid state of water. The solid, liquid and gaseous states of the things around us depend upon temperature and temperature covers a wide range.
The chilliest temperature in the universe is absolute zero, which is minus 273.2 degrees Centigrade. At this point, every substance loses all its heat and can get no colder. Heat is the energy which keeps the atoms and molecules of a substance in motion. At absolute zero, all this energy is gone and the atoms and molecules are still.
On earth, we never reach absolute zero and even in a laboratory the job is almost impossible. However, we can make things very hot for ourselves and we have furnaces that can run up to many thousands of degrees. Normal temperatures, however, range between 50 or so below to 100 or so above zero. The ground, the air and the oceans exist in this temperature range,
An iron poker is frozen solid at about 1500 degrees. Water becomes solid ice at about 0 degrees. Copper is frozen solid at 1080 degrees. Each substance freezes solid at a certain temperature, which is its own special freezing point. At normal temperatures, iron and copper are frozen solid and the ocean is liquid. Copper does not melt into liquid form until it reaches 1083 degrees. Iron must reach 1583 degrees before it melts into liquid form.
The melting point of a substance is the same as its freezing point.
At 0 degrees, solid ice melts into liquid water. If we add more heat, a liquid substance reaches its boiling point and becomes a gas. Boiling water turns to gaseous vapor and its molecules fly off separately into the air. Copper boils and becomes gas at 2300 degrees, iron reaching boiling point at 3000 degrees.
Oxygen and nitrogen, the chief gases of the air reach their boiling points far below normal temperatures. Oxygen boils into its gaseous form at minus 183 centigrade degrees and nitrogen at minus 195 degrees. Carbon dioxide, neon and the other rare gases of the atmosphere also boil far below normal temperatures. We cannot boil the air because it is already boiling. It reaches boiling point and becomes a mixture of gases at far, far below zero.
When a substance reaches its boiling point, its molecules have enough heat energy to separate from each other and fly off in all directions. As this heat energy is lost, the molecules lose some of their speed: Below boiling point, their natural attraction for each other is strong enough to make them cling together in liquid form. At freezing point, the molecules are so slow that this attraction can hold them together in rigid formation