Eli5 what would happen if you had water in a completely sealed container and brought it past boiling temp

Question

Would it just turn into a pressurized container full of steam? Would the water stay water but just like, really hot?

In: 98

Answer 1

A perfect example of the situation the poster described is the common household water heater. If the temp control fails and the relief valve is damaged or in some way purposely disabled, the results are catastrophic. For an eye-opening demonstration, check the Myth Busters water heater explosion on YouTube.