Water boils faster in a kettle because the pressure is higher in there and the boiling point is reduced... But according to the phase diagram for water the line between liquid and gas is increasing when temperature and pressure increase right ?
So how is it possible that by,let's say, walking on an increasing line to the top (because we increase the pressure in a kettle) the boiling point is less ?
Sorry, my native language isn't English so maybe I didn't explain so good my question :)
Water only boils faster (than whatever else were comparing) in a kettle because it's supplying more heat to the water than whatever we are comparing it to.
There should be minimum pressure buildup in a kettle. They have some mechanism to release vapour to ensure that it doesn't turn into a high pressure high temperature accident that injures people.
If kettles were pressurized, you could heat it past 100°C as a liquid, then as soon as it leaves the kettle it would begin to vaporize in the outside air pressure. There's no real reason to pressurize the container though. It's too unsafe.
Water boiling faster is not because the pressure. Pressure in a kettle is atmospheric. When pressure is higher, the boiling temperature becomes higher and boiling is slower as you discovered. Boiling can carry away heat. Without heating, the water temperature will decrease in a kettle. This will reduce boiling rate. Heating is critical that keeps the water temperature at boiling temperature and making the boiling fast.
