At what vacuum does water boil?
At standard atmospheric pressure, water boils at 100 degrees Celsius, or 212 degrees Fahrenheit. However, in the absence of atmospheric pressure, also known as a vacuum, the boiling point of water decreases significantly. This is due to the fact that at lower pressures, the intermolecular forces between water molecules are weaker, causing the water to vaporize at lower temperatures. In a vacuum, the boiling point of water can be as low as -218.6 degrees Celsius (-361.48 degrees Fahrenheit) at absolute zero (-273.15 degrees Celsius, or -459.67 degrees Fahrenheit). This is known as the critical point, beyond which water cannot exist in its liquid form. At lower vacuum levels, the boiling point of water decreases gradually with decreasing pressure, until it reaches a point where the water molecules have enough energy to overcome the intermolecular forces and evaporate rapidly, creating a violent and rapid boiling effect known as a “vacuum blaze”. This phenomenon is commonly observed in vacuum chambers during the process of pumping down to high vacuum levels.
