The student is told of Ferdinand Magellan's success at circumnavigating the world, and that he lost a day when he arrived at the Cape Verde Islands near Africa. The student is then asked to explain this (based on the concept of the International Dateline).
keywords: Ferdinand Magellan, circumnavigate, lost day, Cape Verde, International Dateline
swf file: ca_coordsmotion_missingday.swf