Why don't ships go straight? | Great Circles?

Ships don’t go straight because the Earth is round, and they follow great circles, which are like the shortest path on a ball.

Imagine you're playing with a ball, and you want to get from one side to the other. If you draw a line across the ball’s surface, that’s the fastest way, it's like taking a shortcut across the ball instead of going all the way around. Ships do something similar when they travel long distances: they follow these great circles because it helps them save time and energy.

When you look at a map, straight lines seem like the best way to go, but maps are flat! The Earth is like a big round ball, so if you draw a line from one place to another on a curved surface, it actually looks like a curve on the map. That’s why ships often appear to take a “bendy” path, they’re just going straight on the real, rounded world.

Think of the Earth as an orange. If you want to get from one end of the orange to the other, you’d probably go through the middle instead of around the sides, that’s the great circle! Ships do something like that when they travel across oceans.