## Physics: Principles with Applications (7th Edition)

A liquid boils when its saturated vapor pressure equals the external pressure. From Table 13–3, we see that the saturated vapor pressure of water at $20^{\circ}C$ is about 2330 Pa, or about 2.3 percent of normal atmospheric pressure. If $20^{\circ}C$ water is placed in a vacuum chamber and the pressure is reduced to that value, the water will boil. You can find videos of this on the Internet.