There are two different types of glow sticks. There are glow sticks with a glass vial in them and some skinnier ones without but we will be talking about the thicker ones with a glass vial. On the outside of the vial there is something called H2O2 or hydrogen peroxide. On the inside of the vial there is something called phenyl oxalate esters or bis. When you bend or snap the glow stick it starts to glow which mean you’ve snapped the vial inside and the hydrogen peroxide has made contact with the phenyl oxalate esters. When the substances come in contact with each other the reaction occurs which makes the molecules from both substances absolutely freak out. This reaction uses kinetic energy to produce the color that you see in your glow