Mary Emily Sinclair facts for kids

Mary Emily Sinclair (born September 27, 1878 – died June 3, 1955) was an important American mathematician. She studied special types of shapes in math called algebraic surfaces. She also worked on a field called the calculus of variations. Mary Emily Sinclair was the first woman to earn a special high-level degree, called a doctorate, in mathematics at the University of Chicago. Later, she became a top professor of mathematics at Oberlin College.

Early Life and Learning

Mary Emily Sinclair was born in Worcester, Massachusetts, on September 27, 1878. She was one of five children. Her father was a mathematics professor at the Worcester Polytechnic Institute. Her mother taught English and languages.

Mary Emily graduated from Worcester Classical High School in 1896. She then became a student at Oberlin College. While there, she was president of the Oberlin branch of the YWCA. She graduated with a Bachelor of Arts degree in 1900. She was also part of Phi Beta Kappa, an honor society.

After college, Mary Emily taught at a seminary in Hartford, Connecticut. She also continued her studies at the University of Chicago. She earned a master's degree in mathematics in 1903.

She taught briefly at Lake Erie College in 1903. Then, she taught at the University of Nebraska from 1904 to 1907. During this time, she kept studying at the University of Chicago.

She earned her Ph.D. (doctorate) in 1908. Her special research was about finding the smallest area of a surface. This work was part of the calculus of variations. She was the first woman to earn a doctorate in mathematics at the University of Chicago. Her achievement helped many other women get doctorates there later.

Career and Later Life

In 1907, Mary Emily Sinclair started teaching at Oberlin College. She stayed there for 37 years. After getting her doctorate, she became an associate professor.

She adopted two children as babies in 1914 and 1915. In 1915, she helped start the Mathematical Association of America. This group helps math teachers and students.

She became a full professor in 1925. In 1939, she became the head of the mathematics department at Oberlin. She was named Clark Professor of Mathematics in 1941.

Mary Emily retired in 1944. However, she continued to teach math to US Navy students for two more years. She taught them through Berea College.

She returned to Oberlin in 1947. In 1950, she was injured in an accident. She moved to Belfast, Maine, in 1953. She lived there with her daughter-in-law. Mary Emily Sinclair passed away on June 3, 1955.

Sinclair's Special Surface

Mary Emily Sinclair's master's thesis in 1903 was about a special surface. It was called Concerning the discriminantal surface for the quintic in the normal form: .

In her work, she used special math tools to change equations. This helped her to sort out different types of equations. She could tell how many real answers they had.

Physical models of her special surface were made from her designs. A German company created these models. Later, in 2003, a sculptor named Helaman Ferguson made a stone carving based on her surface.