In the mid-1800s, English physicist and chemist, Michael Faraday gave a series of nineteen lectures aimed towards young adults with the hopes of conveying scientific phenomena. His intentions were to raise awareness, inspire them and generate revenue of the Royal Institution. This series became known as the Christmas lectures, and still continues today. By the early 20th century, the public notoriety of physicists such as Albert Einstein and Marie Curie, and inventions such as radio led to a growing interest in physics. In 1921, in the United States, the establishment of Sigma Pi Sigma physics honor society at universities was instrumental in the expanding number of physics presentations, and led to the creation of physics clubs open to all students.