Lesson 39: Maps and Directions
A compass connects Earth's magnetic field with directions on a map. The lesson covers orientation, symbols, scale, and the different trade-offs involved in representing a round Earth on flat maps.
Key Ideas
- Left and right change when we turn around. North, east, south, and west give us shared directions.
- The four cardinal directions help us describe where places are. Sunrise gives an approximate clue to east.
- A compass needle lines up with Earth’s magnetic field. Magnetic north and true north are not always in the same direction.
- A map shows selected information. Its direction marker, key, and scale help us understand it.
- Flattening Earth’s round surface onto a world map changes some shapes, sizes, or distances. Different maps make different choices about what to show accurately.
Vocabulary
- Cardinal directions: North, east, south, and west: local geographic directions that do not change when you turn your body.
- Compass: A tool with a magnetic needle that helps us find direction.
- Compass rose: The N, E, S, W symbol printed on a map showing how the map lines up with the real- world directions.
- Map: A drawing that shows selected features of a place and where they are.
- Projection: A way of showing Earth’s curved surface on a flat map. Some shapes, sizes, or distances become distorted.
Discussion Questions
- A navigator wants useful angle information, while someone comparing countries wants accurate relative areas. What trade-offs do Mercator and Gall-Peters make, and why would a map's purpose matter?
- If you shrank a basketball down to the size of a coin without cutting it, could you flatten its surface without any wrinkles or stretching? What does that tell you about every world map ever made?
- Africa, Europe, and North America are drawn close to their true sizes on a Gall-Peters map, but their shapes look squashed. Why might a mapmaker accept that trade-off?