Name The Year: General Augustin de Iturbide crowned Augustin I, 1st emperor of Mexico.?

Questions

What was the former name of Belize?

What was the former name of Kampuchea?

What was the full name of the eminent physicist who dipped a piece of o ring into a glass of water in a demonstration, & proved that low temperatures at the launhpad were responsible for the challenger disaster?

What was the Graf Zeppelin?

What was the hometown of Casey's baseball team in the poem "Casey At The Bat"?