Clair Patterson—20th Century Geologist

“How old is the earth and the solar system?” This question puzzled scientists for hundreds of years. It was an Iowa scientist, Clair Patterson, who solved this mystery in the 1950s. His research and testing took seven years of work. His methods and results were often questioned. Over 50 years later his results still stand.

Clair Patterson grew up in Mitchellville, Iowa. His interest in science started as a young boy. He spent hours experimenting with a chemistry set in the basement. His first science lab was on the banks of the Skunk River. In 1943 he graduated from Grinnell College. During World War II (1939-1945) Patterson worked on the atomic bomb project known as the “Manhattan Project.”

Changing Careers

He spent many years in college studying to become a chemist. In 1950 he graduated with the highest college degree, a Ph.D., in chemistry from the University of Chicago. Clair Patterson became an expert using special scientific equipment in the science of spectroscopy (the study of optical spectra). There were not many scientists in the country who understood this type of equipment better than Clair Patterson.

Harrison Brown, also a scientist, invited Clair Patterson to work on a problem with him. He wanted Patterson to help determine the age of the planet Earth. This was a mystery to scientists. Brown had a rough idea of how this procedure could be done. What he needed was a chemist who knew about spectroscopy. Although Clair knew all about spectroscopy, he knew nothing about geology or separating minerals. To study the age of Earth Patterson would need to study and analyze the lead in ancient iron rocks and meteorites.

Cleaning Up in the Lab

The research to determine the age of the Earth was conducted at the University of Chicago and then California Tech. Patterson worked in old, dirty buildings. He had to measure very tiny amounts of lead. During his research he discovered that information already published on the lead content in objects was wrong. He found that common objects such as lead pipes, food cans, unfiltered air and lead paint were very harmful to humans. He learned that the Earth’s atmosphere was far more contaminated than anyone knew.

Before he could continue his measurements for determining the age of the Earth, Clair had to get rid of all lead from his lab. He wanted to dispose of every possible molecule of lead. This led to the beginning of the state-of-the-art “clean” lab. The Patterson lab and his new procedures for using clean samples led the way for future studies of the environment.

When Clair completed the final step of his research on the age of the Earth, a measurement was taken at the Argonne National Laboratory in Illinois. The test results showed that the earth and the solar system were 4.55 billion years old.

The Dangers of Lead Increase

Clair Patterson then turned his attention to studying lead. He studied how much lead the ancient Romans used with their coin making process. He traveled to Antarctica to pioneer the way to capture clean core samples. Through all this Patterson collected more and more data on a clear, oily liquid called tetraethyl lead. Lead was everywhere in the atmosphere. It was sprayed on fruit to keep insects away. Lead was added to gasoline to stop engines from “knocking.” Even though it was known to be very dangerous to people, lead was still widely used. Too much lead in the body was known to cause blindness, cancer, kidney failure, hearing loss and even death.

Patterson researched the effects of lead on people. How much lead was getting into the environment? At what level would lead became dangerous to the human body? Those were the questions the scientist needed to answer. He started his research by studying history. He studied the bones of 1,600-year-old Peruvian Indians. The tests helped scientists to understand the impact of lead manufacturing on humans. He found lead amounts in the human body had gone up between 500 and 1,000 times. Patterson’s research showed that everyone suffered. All humans were being contaminated in some way. In 1970 Patterson spoke before a special U.S. Senate hearing on air and water quality. His experiences and research findings were important turning points that led to the passage of the Clear Air Act.

A Lasting Impact

Clair Patterson is remembered as an important 20th century scientist. Some consider him the most influential geologist of the century. He was influential in stopping the use of leaded gasoline in this country. He pioneered laboratory methods that changed the way future environmental and medical research would be done. Around the world tributes to Clair Patterson include an asteroid named in his honor and a mountain peak in a remote part of Antarctica’s Queen Maude Mountains named after him. They are symbolic of his greatness.

Clair Patterson is a scientist who made a change in his life to adapt to new situations. He started his career as a chemist and became a geologist when his work required new skills and knowledge. His findings changed the way we live today. The world is healthier because of Clair Patterson’s struggles to improve the quality of the air we breathe.


  • Tim Lane, "Saint Patterson and His Duck Soup," Iowa Heritage Illustrated, 86, no. 2 (Summer 2005).


Adapted from original article published in Iowa Heritage Illustrated, provided courtesy of State Historical Society of Iowa.