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

The sealed radiator, with fixed volume and contents, is under high pressure because of the high temperature. From Figure 13-22, we see that the boiling point of water increases at higher pressure. So, the water is in a liquid state even though the temperature is much higher than the normal $100^{\circ}C$. If you are unwise enough to open the radiator cap, the sudden drop in pressure causes the superheated water to boil, and the emitted steam and expelled water can burn you.