- Alabama (Wikipedia)
Alabama (/ˌæləˈbæmə/) is a state in the Southeastern region of the United States, bordered by Tennessee to the north; Georgia to the east; Florida and the Gulf of Mexico to the south; and Mississippi to the west. Alabama is the 30th largest by area and the 24th-most populous of the U.S. states.
- Helen Adams Keller (June 27, 1880 – June 1, 1968) was an American author, disability rights advocate, political activist and lecturer. Born in West Tuscumbia, Alabama, she lost her sight and her hearing after a bout of illness when she was 19 months old. She then communicated primarily using home signs until the age of seven, when she met her first teacher and life-long companion Anne Sullivan. Sullivan taught Keller language, including reading and writing. After an education at both specialist and mainstream schools, Keller attended Radcliffe College of Harvard University and became the first deafblind person in the United States to earn a Bachelor of Arts degree.
- Focal length (Wikipedia)
The focal length of an optical system is a measure of how strongly the system converges or diverges light; it is the inverse of the system’s optical power. A positive focal length indicates that a system converges light, while a negative focal length indicates that the system diverges light. A system with a shorter focal length bends the rays more sharply, bringing them to a focus in a shorter distance or diverging them more quickly. For the special case of a thin lens in air, a positive focal length is the distance over which initially collimated (parallel) rays are brought to a focus, or alternatively a negative focal length indicates how far in front of the lens a point source must be located to form a collimated beam. For more general optical systems, the focal length has no intuitive meaning; it is simply the inverse of the system’s optical power.
- Keller was born on June 27, 1880, in Tuscumbia, Alabama, the daughter of Arthur Henley Keller (1836–1896), and Catherine Everett (Adams) Keller (1856–1921), known as “Kate”.
- She [Helen Keller] died in her sleep on June 1, 1968, at her home, Arcan Ridge, located in Easton, Connecticut, at the age of 87.
- Anne Sullivan (Wikipedia)
Anne Sullivan Macy (born as Johanna Mansfield Sullivan; April 14, 1866 – October 20, 1936) was an American teacher best known for being the instructor and lifelong companion of Helen Keller.