How is an afterimage measured?

Time, space, sound, liquid, solid, love, emotions, responsibility, tempo's, just about anything tangible.

In feet. (5,280)

Reality in reference to the physical world or nature can be observed and measured. But reality also consists of things with which we can't observe and measure such as values, morality, and the...

Water deposited by rain or artificial irrigation.

Because a perimeter is measured in linear units while an area is measured in square units.