Boiling Point of Water

This the the key feature of multi-stage flash distillation. Water boils at different temperatures in different pressures. You might know that water boils at lower than 100°C at higher altitudes (b/c there is lower air pressure), and that cooking instructions are different for “high altitude cooking”. Why is this? Lets start by defining what is boiling? “The boiling point of water is the temperature at which its vapor pressure equals the atmospheric pressure”. What does that mean? Well a simple way to think about it is like this. When water boils it makes bubbles, and its easier to make bubbles when there is less pressure pushing against the bubble. Less pressure, like higher altitudes, create an easier environment to make those bubbles. Easier to boil means less energy and a lower temperature to reach vapor point, or boiling. In contrast pressure cooker creates higher pressures so the water DOESN'T boil until hotter or higher temperatures.