World geography: maps, projections, and spatial tools (grade 9)
Maps are tools for answering questions about where things are. Every map makes trade-offs, so a good map reader knows what each map gets right and what it bends.
Latitude, longitude, and time zones
💡 Latitude tells how far north or south a place is, and longitude tells how far east or west.
Lines of latitude run east and west around the globe. They measure distance north or south of the equator, which is 0° latitude. The North Pole is 90° N and the South Pole is 90° S. A bigger north number means farther north. Below the equator, a bigger south number means farther south.
Lines of longitude run from pole to pole. They measure distance east or west of the prime meridian, which is 0° longitude and passes through Greenwich, England. N or S tells you the hemisphere north or south of the equator. E or W tells you the hemisphere east or west of the prime meridian.
Earth turns a full 360 degrees each day. Since a day has 24 hours, the sun seems to move 360 ÷ 24 = 15 degrees of longitude each hour. That is why time zones are about 15 degrees wide.
- To place 30° S, 120° E: the S means south of the equator, so the Southern Hemisphere.
- equator
- the line at 0° latitude, halfway between the poles
- prime meridian
- the line at 0° longitude, through Greenwich, England
- hemisphere
- half of the globe