Once grasped the Lorentz Transformation, we can use math to compute and infer the time dilation and length contraction.

in above, the sneezing by Einstein measured in his reference frame is 3ct and 0 position(x), but from the perspective of the car -using car’s frame- the time is 3.46 and position is moved to left by 1.73.

We say moving clocks run slow, because the time is always the shortest at the object’s own framework because for itself, the position can be held still.

An object’s length is always the longest when measured at its rest frame.

Velocity Addition and Relativity of Simultaneity: