## Boiling Points

The scale you use will determine how your numerical answer to the question, “at what temperature does water boil?” Water boils at 212 degrees Fahrenheit, 100 degrees Celsius, 373.15 degrees Kelvin, and 671.67 degrees Rankine.

## Temperature Scales

The amount of heat in the water determines at what temperature does water boil; each scale simply uses different numbers to represent the same amount of heat. More information on how the scales compare can be found here.

## The Boiling Process

Asking “At what temperature does water boil?” also leads to the question of how boiling the boiling process happens. Boiling is the process by which a liquid, in this case water, becomes a gas. When water is heated, its molecules gain energy and begin to move faster.  As the water reaches its boiling point, these excited molecules begin to form bubbles and eventually escape the water’s surface as a gas. The gas released is called steam or water vapor.

## Are boiling points the same everywhere?

While water boils at 100 degrees Celsius at sea level, at 10,000 feet elevation, it will boil at 90 degrees Celsius. This occurs because at higher levels of elevation, there is less atmospheric pressure on the water, meaning that the water requires less energy to escape the surface. Every liquid has its own boiling point due to differing physical qualities. For example, at sea level, Acetone boils at 50.5 degrees Celsius, jet fuel boils at 163, oxygen boils at -183, and tar boils at 300. Thus, it is important to pay attention to altitude, temperature, and the physical properties of the liquid in question when examining boiling points.

For further information, check out this handy list of the boiling points of many substances.

## Why Does Water Boil?

Why does water boil? The answer to the question “Why does water boil” is important knowledge for everyone, as water is part of the basis of human life and provides many health benefits. Boiling water has a number of uses, includingboiling to purify water, sterilizing medical tools, cooking, and as a starting material or solvent in chemical reactions. The boiling point of water and the process of boiling itself is determined by various chemical properties of the substance.

## Why Does Water Boil: Boiling Water for Food Preparation

One place to begin investigation of the question “why does water boil” is to survey the most familiar usage of boiling water: food preparation. A variety of simple foods including spaghetti and hard boiled eggs can be prepared simply by placing them in a pot of boiling water. One Food Network show even has the tongue-in-cheek title “How to Boil Water.” With a subject this familiar, a few myths and sayings have naturally arisen. “A watched pot never boils,” says one popular expression. Of course, this is not technically true, an intense gaze having absolutely no effect on the boiling point of water.

## Does adding salt to water change anything besides taste?

Something that does affect the boiling point of water, however, is the old tradition of throwing a pinch of salt in the pot. Adding salt to water will raise the boiling point of the water due to the reduction in vapor pressure. This means that the water will boil more slowly, which can be an advantage when trying to hard boil the perfect egg. For an in depth analysis on these effects, referring to Volker Thomsen’s article “The Boiling Point of Water” written for The Physics Teacher may be helpful, or simply just continue reading.

## Why Does Water Boil: The Chemistry

When asking why does water boil, people may come across such phrases as “vapor pressure,” “atmospheric pressure,” and “heat of vaporization.” While the boiling point of water is listed as 100 degrees Celsius, the truth is that the boiling point given in the literature is that for standard pressure, approximated as 1 atm.