What is the boiling point of water in degrees Celsius?

Water reaches its boiling point at 100 degrees Celsius under specific conditions. This temperature is a fundamental concept in science and everyday life, representing the point at which liquid water rapidly transforms into a gaseous state, known as steam. This transformation occurs when the water molecules gain enough energy from heat to overcome the forces holding them together as a liquid, allowing them to escape into the air as vapor.

The key condition for water to boil at precisely 100 degrees Celsius is standard atmospheric pressure, which is typically found at sea level. Atmospheric pressure is the weight of the air pressing down on the surface of the water. When water is heated, its vapor pressure increases. Boiling commences when the vapor pressure of the water equals the surrounding atmospheric pressure, allowing bubbles of vapor to form and rise throughout the liquid.

Interestingly, the boiling point of water is not always 100 degrees Celsius. If you were to boil water at a higher altitude, such as on a mountain, you would find that it boils at a lower temperature. This is because atmospheric pressure decreases with increasing altitude, meaning less energy is required for the water molecules to escape into the gaseous phase. Conversely, increasing the pressure, like in a pressure cooker, will raise the boiling point of water.

The Celsius scale itself is intrinsically linked to water's phase changes. It was invented by Swedish astronomer Anders Celsius in 1742. While his original scale had 0 degrees as the boiling point and 100 degrees as the freezing point, it was later inverted to the scale we use today, with 0 degrees Celsius as the freezing point of water and 100 degrees Celsius as its boiling point at standard atmospheric pressure. This makes the Celsius scale a very intuitive way to understand temperature in relation to water.