Time reversal is a concept in physics where the direction of time is flipped, allowing events to unfold in reverse order. This idea challenges our everyday experience, as we perceive time as a one-way street, moving from past to present to future. In theoretical physics, time reversal symmetry suggests that the fundamental laws of nature remain unchanged if time were to run backward. In quantum mechanics, time reversal can be applied to understand particle interactions. For example, if a particle collision is reversed, the resulting paths of the particles can still obey the same physical laws. This principle helps scientists explore the nature of time and its relationship with entropy and thermodynamics.