Kai takes a hamburger off of the grill and puts a piece of cheese on it. Explain how and why the cheese melts when Kai puts it on the hamburger

 The cheese melts on a hamburger because the burger has more thermal energy than the cheese, and because thermal energy travels from a warmer substance to a cooler substance, the cheese will melt due to substance reaction, and conduction coming from the hamburger onto the cheese when the cheese is placed on the hamburger.

Explanation: Because of thermal energy transfer. I hope I helped! :)