If water boils at 100°C, and boiling is the process of turning liquid into gas, why are bathrooms full of steam when showering at only 40°C?
In: Chemistry
The issue is the definition of temperature. You’re using it in a way that makes it sound like “the object is at that temperature” and that’s what is confusing you.
Temperate is the AVERAGE kinetic energy per unit volume. If you measure actual kinetic energies at a molecular level, you’ll find they are spread out over a range of values. If you plot those, you get a curve called the Maxwell Boltzmann distribution. It has a big lump in the middle and a long tail of “hotter” bits. Due to the math, the temperature is in the middle of that lump, because that’s literally the definition.
So when you have water at, say, 30 degrees, this implies the average particle is energy is 30. If you plot that curve and then put a line at 100, you’ll notice there are still particles beyond that 100 line. Those will “boil” even though the water as a whole is well below the boiling point. If you increase the temperature to, say, 50, that curve moves and more and more of the particles are past the line and the rate goes up.
As you continue increasing the temperature, eventually you hit a point where the average particle has that amount of energy. At that point the rate of gasification is great enough that the water is seen to be bubbling en mass, or “boiling”. We call that 100C. Now the situation is reversed: removing heat at this point will leave you with the particles that were still below the boiling point, or were after the random processes.
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