* Endothermic processes absorb heat from their surroundings. This means the system (in this case, the copper) gains energy.

* Exothermic processes release heat into their surroundings. The system loses energy.

Why melting copper is endothermic:

* To melt copper, you need to provide heat energy to break the strong bonds between the copper atoms in its solid state.

* This energy is absorbed by the copper, causing its temperature to rise until it reaches its melting point.

* Once the melting point is reached, the energy continues to be absorbed, breaking the remaining bonds and transitioning the copper from solid to liquid.

Think of it this way: You need to put energy (heat) into the system to melt copper, so the process is endothermic.