By 1908, her parents separated, and Kathleen and her surviving siblings were brought to Essex by their mother. Kathleen excelled through elementary and high school. She entered Bedford College, University of London aged 16, where she chose to read physics because she was worried that the only career open to women maths graduates was teaching. In 1922, she was invited to join Nobel physicist Professor William Bragg’s research school.
She collaborated with international scientists to produce the International Tables or ‘crystallographer’s bible’, comprehensive tables for determining crystal structure. In 1927, Kathleen married Thomas Lonsdale. He encouraged her to continue her scientific research. In 1929, she made her first major discovery, she demonstrated conclusively that the benzene ring was flat.