The discovery of oil in Pennsylvania in 1859 was a major factor in the change of energy sources in the United States between 1850 and 1900. Prior to this, the primary sources of energy in the country were wood, water, and coal. However, with the discovery of oil, kerosene became a cheaper and more efficient source of fuel for lighting homes and businesses, leading to a decline in the use of whale oil. The development of the oil industry also led to the growth of other industries, such as the production of gasoline for transportation. This shift towards oil as the primary source of energy laid the foundation for the oil-dependent society that the United States has become today.