A lesson in perspective.

Prepare a globe if one is available, the free Equal Earth outline map and our projection comparison tool. Students need a pencil and room to note an initial prediction. The activity suits roughly ages 11 and up; adapt the mathematical detail to the group. The outline is supplied as JPEG for easy printing and SVG for editing. Fit it to the page and print in landscape.

Ask: “How many Greenlands could fit into Africa by area?” Have each student record a prediction before showing a comparison. Then ask whether north has to be at the top of a map. Collect reasons, not just answers.

Move the comparison tool from 0° to 30° to 60° latitude. The marked circular patches have the same surface area on the globe. Students should describe how their shapes and displayed sizes change. On spherical Mercator, the local area factor is 1 at the equator and 4 at 60°. In Equal Earth, equal areas retain equal areas on the map.

Ask students to explain why the same Mercator effect appears in the southern hemisphere. Then ask why “this map preserves area” does not mean “this map preserves distance”.

On the outline, mark the equator and identify Africa and Greenland. Sketch a rough area comparison of about 14:1 using squares, not invented outlines. Compare a Greenwich-centred map with a Pacific-centred map. What moves toward the edge? What stays unchanged? Use the complete source map for labels and the outline for annotations.

Ask each student to finish: “I would use an equal-area map when …, but I would choose another representation when …”. A good answer connects a map property to a task. For example: compare continental area with Equal Earth; plan an actual journey using a suitable navigation tool.

Teacher notes: changing the central meridian does not change real geography or relative areas. North-up is a convention. Straight constant-bearing routes are a Mercator property, not generally shortest routes. A map’s boundaries are editorial data, not consequences of the projection formula.