Final answer:
The second law of thermodynamics is exemplified by the spontaneous heat transfer from a hot object to a colder one, which results in increased entropy, showcasing the natural tendency for systems to become more disordered.
Step-by-step explanation:
A classic example of the second law of thermodynamics involves observing the natural transfer of heat from a hot object to a colder one, without the use of an external work source. This follows the second law stating that heat spontaneously flows from a hotter to a cooler body and is a reflection of the law's directionality, which is aligned with the increase in entropy. Entropy is a measure of a system's disorder and the unavailability of energy to do work. Thus, when heat transfers from hot to cold, entropy increases, exemplifying the second law's prediction that systems tend towards greater disorder and less available energy for work.