The methods of cracking chain molecules in petroleum have expanded over the past century just as every other invention and process has been modified for the benefit of the consumer. Thermal cracking was developed one hundred years ago as a way to salvage more useful products (gasoline, naphtha, diesel) from the tower residues and heavy fractions. This was the first commercial conversion process. By using hydrogen abstraction and beta scission, engineers were able to “chop up” the long chain alkanes that are the responsible for the heaviness of the residue into shorter C-H chains. Although the first scientists may not have completely known the chemistry of the reaction, they knew that this process was going to be a crucial part of petroleum refineries, especially with the boom of automobiles in the early 20^th century. The influx of automobiles may have been responsible for the beginning of the use of thermal cracking, but it also may have been its demise. The process is barely ever used for increasing the yield of lighter products since it proved to produce low octane numbers (compared to its more chemically accurate counterpart, catalytic cracking). Thermal cracking is still used in today’s refineries, yet most of the time it is utilized for the production of ethylene.