Freezing, Melting, and Boiling Points of Solids, Liquids, and Gases in general Use Today

The temperature at which a liquid boils and turns into a gas. The boiling point temperature will be lower if the atmospheric pressure is decreased. For example the boiling point of pure water at standard atmospheric pressure (or sea level) is 100°C (212°F) while at 10,000 feet (3,048m) it is 90.39° C (194.7°F). This decrease will affect the time it takes to cook anything in water to the extent that any food that requires five minutes to prepare at sea level will take around 20 minutes at 3km (10,000 feet). In theory you could also calculate your altitude by recording the temperature water boils at.

Solvent based liquids will generally have a lower boiling point than water. In other words they will require less heat to turn them into vapour. Liquids with a much lower boiling point than water are generally classed as flammable.

The temperature at which a liquid becomes a solid. The freezing point temperature will be higher if the pressure is increased. This may not be by a noticeable amount due to the volume change upon melting being much smaller than the volume change (expansion) when boiling. For example the freezing point of pure water at standard atmospheric pressure (or zero feet) is 0°C (32°F) while at 11km (6 miles) above sea level it would only be 0.001°C higher.

The only known liquid that does not freeze, even at absolute zero, is liquid helium unless it is under pressure.

The temperature that a solid substance becomes a liquid. Some solids do not have a liquid state and will change directly from a solid to a gaseous state. This is called sublimation, e.g. Carbon Dioxide (dry ice).

The terms melting point or freezing point are often interchanged depending on whether a substance is being heated or cooled. For liquids it is known as the freezing point and for solids it is called the melting point. The melting point of a solid and the freezing point of the liquid are normally the same.

Table of Boiling and Melting/Freezing Points at Sea Level (Standard Atmospheric Pressure). The information is provided in centigrade (Celsius).