Whilst it is travelling through the air two things are happening: it is cooling down very rapidly (a process known as quenching) and it is being deformed.
The deformation of a droplet depends on the speed at which it is erupted from the volcano, its surface tension, the viscosity (thickness) of the magma and the resistance it experiences as it travels through the air.
Pele's tears are interesting to volcanologists because trapped within the glass droplet are bubbles of gas and particles called vesicles.
When the gases trapped within the vesicles of Pele's tears are analyzed they can provide a great deal of information about the chemical composition of the magma chamber.
[2] This information can be used to determine the explosive nature of an eruption and help to understand the complex processes occurring within volcanos.