How long is a coastline — and would two people ever measure the same number?
Tracing a wiggly coast on a map app, or arguing whether a country's border or coast is 'long' — zoom in and even more wiggles appear that weren't there a second ago.
Talk about it
- Trace a coast on a map with your finger, then with a single straight ruler step — guess which one is 'longer' before you check.
- Ask: if you and a friend both measured our country's coast carefully but used different rulers, would you get the same number?
- Find the wiggliest coastline you can on a map and the smoothest one — guess which one's length grows the most when you zoom in.