Lines of longitude run vertically from the top of Earth to the bottom. They divide the world into segments like an orange, meeting at the north and south poles. Lines of longitude are called meridians. Like latitude, they also have a starting point – at Greenwich, London. This is called the prime meridian. The longitude of a place is described in terms of how far east or west of the prime meridian it is. Longitude is based on Earth’s rotation through 360 degrees, which happens once every twenty-four hours. Put another way, Earth turns 180 degrees every twelve hours or 15 degrees every hour. Because of this connection between time and longitude, Cook could work out his approximate longitudinal position if he knew the time in Greenwich.
source SCHOOL JOURNAL LEVEL 4 MAY 2016 CAPTAIN
COOK CHARTING
OUR
ISLANDS by Melanie Lovell- Smith |
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