near the magnetic poles of the the Sky glows with The Spectacular display of green and pink lights why does this happen

If steel is more dense that lake water, why can a boat float

Two students, each riding bicycles, start from the same apartment building and ride to the same building on campus, but each takes a different route. the first student rides 1100 m due east and then turns due north and travels another 1430 m before arriving at the destination. the second student heads due north for 1930 m and then turns and heads directly toward the destination.at the turning point, how far is the second student from the destination?

Ascientific blank must be testable and capable of being proven false?