If you need to speed up the rte at which your potatoes are cooking in boiling water, would it be better to turn up the heat or use a pressure cooker? why?

2 answers

Use a pressure cooker. Why? Because at increased pressure, the boiling temperature is increased as well as the steam will help cook it. Turning up the heat on a stove top will get the water to the boiling point faster but it won't get the water any hotter than 100 C.
A pressure cooker raises the water (and steam) temperature, and makes things cook must faster. Turning up the heat on a pan of water exposed to the atmosphere does not increase the temperature of the water, but does increase the heat transfer rate somewhat.