While popularly known for his role as one of the United States’ founding fathers, Benjamin Franklin was also a renowned scientist who made a number of substantial contributions in the field of Earth science. Affectionately known as Dr. Franklin (even though he never received his Ph.D.), he published numerous scientific papers—mostly on electricity. Franklin became a scientist because he was insatiably curious about the world around him. He wanted to know how things worked and figure out ways to make them better.
In 1743, Franklin compared weather observations in letters he received from friends in other colonies. He was one of the first to observe that North American storms tend to move from west to east, and predicted that a storm's course could be plotted. He even made some of the first-recorded weather forecasts in his Poor Richard’s Almanac, a 25-year publication that Franklin first published in 1732 under the pseudonym of Richard Saunders.
In 1752, Franklin, along with his son William, performed his famous kite-flying experiment which proved that lightning is a naturally-occurring electrical phenomenon. The kite was constructed with a sharp metallic wire situated on top and at the end of the kite string, and a key tied to the end of the string with a silk ribbon. When Franklin saw loose threads on the kite string stand up, he grounded the makeshift insulated conductor by touching his knuckle to the metal key on the string. Consequently, he observed a passing spark between his knuckle and the key, which presented the final proof of lightning's electrical nature. Miraculously, the charge was not strong enough to be fatal to Franklin or his son. (Under normal circumstances, a lightning strike can instantly kill any individuals bold enough to fly a kite during a thunderstorm.)
Franklin's Climate Studies
In 1763, Franklin took part in discussions with colonial scholars about the effects of deforestation on local climate. As forests were cleared for farming in the early American colonies, Franklin agreed with the other colonials that "cleared land absorbs more heat and melts snow quicker." However, he thought that many years of observations were necessary before any conclusive evidence could be gathered on the effects of deforestation on the local climate.
In addition to his meteorological prowess, Franklin also published the first scientific chart of the North Atlantic’s Gulf Stream. He hypothesized that the trade winds cause the Gulf Stream by driving warm waters into the Gulf of Mexico, from where they exit by way of the Florida Strait and proceed to form the Gulf Stream. In 1775, on his way to England, Franklin lowered a thermometer into the Atlantic and found the Gulf Stream to be 6° F warmer than the surrounding sea and, subsequently, produced the first chart of the current.
In the last years of his life, Franklin conducted studies on the effects that volcanic eruptions might have on weather patterns, cloud formation, and cloud electrification. He hypothesized that the severe Northern Hemisphere winter of 1783–84 was linked to the volcanic eruption occurring in Iceland in the summer of 1783. Franklin suggested that there was a reduction in the amount of solar energy received at the Earth's surface after the volcanic eruption due to the ash and other particles inserted into the atmosphere.
References
- Fleming, James Rodger, 1998: Historical Perspectives on Climate Change, Oxford University Press, Oxford, 194 pp.
- Parkinson, C. L., 1985: Breakthroughs: A Chronology of Great Achievements in Science and Mathematics, G. K. Hall & Company, Boston, 576 pp.
- Manuel, Diane, 1996: Encyclopedia of Weather and Climate, Oxford University Press, New York, 315 pp.
- J.A. Leo Lemay. Benjamin Franklin: A Documented History. University of Delaware Department of English.
- The Franklin Institute Science Museum, http://www.fi.edu
- ThinkQuest Library, Benjamin Franklin: An Enlightened American
NASA Earth Observatory story by Steve Graham
