Two bodies have different specific heat capacities and come into contact.?

The entirety of the water, as a whole, gains the heat slowly. But what they often do not teach in schools is that the water doesn't heat uniformly. The parts of the water surrounding the copper at first will heat rapidly, while the parts of the water far away from the copper will not. So part of the water will boil fast, some of it will take a longer time to boil.