What is the scientific name for somebody who mends clocks and watches?

Why did Mrs. Johansen ask the girls if they saw anyone while playing near the shore? Surface that curves outward and reflects and spreads light? Why are bright colors difficult to see in a room lot candles? Why would astronaut have a hard time breathing on the moon? What is the propellant in XIPS rockets? When the sun becomes a white dwarf will life on Earth end? What is the order of people and countries that set foot on the moon? What does it the mean by 'life the universe and everything'? Where can you find gravity? What is the howling about? What materials are formed from the core of a supernova? How much of the moon is illuminated by the sun at each position as the moon orbits earth? Where do scientist believe stars came from? What happened in space in 1940? How can telescopes be used in scientific research to study distant celestial objects and phenomena? Which type of star maintains a stable size? What happens to the air when the sun is shining brightly? What is Pluto in Welsh? Did the incas worship the sun? How much does an astronaut weigh on earth if it weighs 27 pounds on the moon?