Understanding circadian rhythms has taken scientists a long time and so much dedication that it has its own form of study: chronobiology. Over decades of research, scientists have concluded that circadian rhythms, which are the changes a person experiences physically and mentally over a 24 hour period, are the body’s natural reaction to light. In order to react, the body has a naturally occurring biological clock that allows molecules to interact with organs and tissue. On a bigger scale, the body contains a master clock, which controls all of the neurons that control the hypothalamus in the brain, which helps process any light information received by your eyes.