What is the difference between language and pictures? Scotland
Blur out the title, etc. and let the students try to figure out what the graphs show. Then piece by piece reveal more to them. Have students write about what they see.
Then with partners(?) look at other maps of the world to see if they can figure out what causes the spikes / troughs. (ex. specific cities, topography etc.)
Maybe link to the website that has pictures for each lat / lon crossing?