Question

Explain why the temperature of water stays the same for a while once it starts boiling?

Answer 1

Whatever it is being heated by has a certain temperature and once the water teaches that equivalent temperature it cannot go higher or lower unless its heat source does too

Answer 2

The temperature remains constant during these phase transitions. Water has a high boiling point because of the strong hydrogen bonds between the water molecules; it is both a strong hydrogen bond donor and acceptor. The first change of phase is melting, during which the temperature stays the same while water melts.