Past the Equator
Sue is traveling by ship from south of the equator to the north.She has a nice little cabin with a bathroom but no window.Sue has no compass nor other instruments. Just the general luggage one brings on board a long cruise. Yet without leaving her room or talking with anyone Sue will be able to tell when the ship has crossed the equator. How?
Why is a manhole cover round and not square? Can you think of two reasons?