Phase Change:This is when substances transition between solid, liquid, and gas states. It's like moving from one floor to another in our staircase analogy.
Thermal Equilibrium:This refers to when all parts of a system are at the same temperature. It's like everyone on one floor of our staircase being at the same level.
Endothermic Process:This is when heat energy is absorbed from surroundings during a chemical reaction. Imagine having to exert more effort (absorb more energy) to climb up the stairs.