Education Technology

Global Greatness

Published on 02/14/2017

Activity Overview

Did you know the shortest distance between two points on the earth is a curve, not a straight line?  In this activity students can move points along a meridian and watch the latitude and distance change accordingly.  The approximate distance provides a reasonable estimate for the follow calculations.


Use a sphere of radius 6400 km as a model of the earth, and meridians and parallels and their use in locating points on the surface of the earth in terms of latitude and longitude.


  • Great Circle
  • Meridians of longitude
  • Prime meridian
  • Equator
  • Latitude
  • Longitude

About the Lesson

The World-Sphere TI-Nspire file contains an interactive globe and five warm up questions.  These questions are ‘self-check’ which means students will automatically see if they got their answers right or wrong, alternatively they can be changed to ‘exam’ and used with the TI-Navigator.  In the main file students can move points along a meridian line to adjust the latitude (approximately) and see the distance automatically computed.  The activity file contains instructions on how to calculate these distances more accurately using appropriate formulas.  Initially points are in the same hemi-sphere, then both hemi-spheres and finally, anywhere on a great circle.   Sample cities with their corresponding longitude and latitude are provided for calculation.