What word names a piece of music or a short school essay?

Which physician, educated partly in Hawaii, led the movement that overthrew the Qing (Manchu) dynasty in 1911? Which physicist, reflecting on the atomic bomb, reportedly said in 1955, "If only I had known, I would have become a wa… A standard piano has 52 white keys and how many black keys? A picture of which actress, "the Love Goddess", adorned an atomic bomb tested at Bikini Atoll in 1946? What word names a piece of rice or a tiny speck of sand? What was the name for the pigtail that was once required in the British Army? Which pilot radioed in 1937: "Gas is running low... we are flying at 1,000 feet"? The pilot's wife in 1986's "Top Gun", Meg joined the military herself in which 1996 film?