GPS

Concept

Your phone knows exactly where you are. But how? No cameras, no wires, just math. Kid discovers that GPS works by drawing circles from satellites, and the spot where three circles overlap is your location.

The Experience

Kid starts with a mystery: "You're somewhere on this map. A satellite says you're 5km from Tower A." That's a circle. You could be anywhere on it. Not helpful yet.

Second satellite: "You're 3km from Tower B." Now two circles. They intersect at exactly two points. Close, but which one?

Third satellite: "You're 4km from Tower C." Three circles. One point where all three overlap. That's you.

Kid does this hands-on: draws circles on a map using compass/radius tools, finds the intersection, and locates the target. Multiple rounds with different tower positions and distances. Then the twist, what happens when the distances have small errors? The three circles don't meet at a point anymore. They form a small triangle of uncertainty. That's why GPS says "accurate to 3 metres," not "exact."

What Math Does The Kid Do?

• Draws circles with given centre points and radii.
• Finds intersection points of two circles, then three.
• Understands that each constraint (distance from a point) eliminates possibilities.
• Explores how measurement error creates uncertainty zones.
• Works with scale, distance, and coordinate positioning.