As new sources of crude oil became available, scientists started to look for other products. Crude oil needs to be refined to produce products, unlike natural gas which could be used untreated. The heating of crude causes different products to be distilled in a tower. Crude oil which is just hydrocarbons (hydrogen and carbon) have different boiling points. Kerosene and diesel require higher boiling points than gasoline, which requires lower temperatures.

This has to do with the ability of hydrocarbons to form chains of hydrogens and carbons. Different lengths of the chains will create different products through distillation. It was also realized that distillation in a vacuum will also cause chains to produce new products. Chemical processes like "cracking" of crude oil breaks long hydrocarbons into shorter chains which produce gasoline. "Reforming" of different by-products with heat, pressure and catalysts, will make chains start chains to create branches. These will also produce new products.

The products from petroleum seemed endless as scientists started to understand the chemistry of the hydrocarbons and how they react under different chemical techniques.