Math Moment: Great Circle Mapper

http://gc.kls2.com/

Great Circle Mapper (GCM) is a great site to share if your family will be traveling by air. Enter the two airport codes, and GCM will tell you the distance between them. It will also draw you a nice map. Adults can learn a thing or two about how flights are planned by clicking on the various hyper-links - I learned that for twin-engine planes always have to be within 60 minutes of an airport in case an engine fails.

As far as the math goes, your kid will improve their number sense about distances - what kinds of places are around 500 miles away? 1000 miles? Also, the idea of great-circle distances is important in geometry. We tend to think about geometry in terms of figures on a flat plane: the shortest distance between two points is a straight line, lines can be parallel, two lines can meet at only one point. But on the surface of a sphere (like the Earth), all the rules change. See this link for a summary and then show your kids on a globe.

http://mathworld.wolfram.com/SphericalGeometry.html