In special relativity, the concept of time dilation arises due to the relative motion between observers. When two observers are in relative motion, they can perceive the passage of time differently. To understand the difference between a moving clock and a non-moving clock, let's consider two observers, one at rest (stationary observer) and the other in motion (moving observer).
From the perspective of the stationary observer, the moving observer's clock appears to be running slower compared to their own clock. This is known as time dilation. The faster the relative velocity between the observers, the more pronounced the time dilation effect.
From the perspective of the moving observer, however, they perceive their own clock to be running normally, and it is the clock of the stationary observer that appears to be running slower. This is a consequence of the principle of relativity, which states that the laws of physics are the same in all inertial frames of reference.
The time dilation effect can be explained by considering that the speed of light is constant in all inertial frames of reference. When an observer is in motion relative to another observer, the relative velocity affects the propagation of light signals. This leads to a stretching or compression of the time intervals observed by each observer.
It's important to note that the time dilation effect is only significant when the relative velocities involved are a significant fraction of the speed of light. At everyday speeds, the differences in perceived time are negligible. However, at very high speeds, such as those approaching the speed of light, the time dilation effect becomes significant and has been experimentally confirmed.
In summary, the difference between a moving clock and a non-moving clock in special relativity is that the moving clock appears to run slower when observed from a stationary frame, while the non-moving clock appears to run slower when observed from a moving frame. This apparent discrepancy arises due to the effects of time dilation resulting from relative motion between the observers.