ELI5: Explain Like I'm 5

Quarter period

A quarter period is a special thing that happens when something goes in a circle. Imagine you are riding a bicycle around a roundabout or spinning a hula hoop around your waist. A quarter period is the amount of time it takes for the bicycle or hula hoop to go around a quarter of the way, or 90 degrees.

Think of it like cutting a pizza into four equal pieces. When you eat one piece, that’s one quarter of the pizza. In the same way, when you ride your bicycle or spin your hula hoop around in a circle, a quarter period is one-fourth of the full circle.

This is important because scientists and mathematicians use quarter periods to help us understand things that move in circles, like satellites orbiting around the Earth or the hands on a clock moving around the face. Basically, anything that moves in a circular motion can be described using quarter periods.