In the 20th century, physicists have understood space and time as being coupled into a space-time manifold, a fundamental arena in which everything takes place. Space-time was considered to have three spatial dimensions and one temporal dimension. Out of the experimental facts, one can conclude that time t we measure with clocks is only a numerical order of duration of motion, i.e. material change in a three-dimensional space. This view allows description of electromagnetic phenomena in a three-dimensional Euclidean space.