Primary school teacher here… work with 5 year olds every day 🙂
Draw a map on an orange.
Cut it into eight pieces vertically.
Eat the orange so just the skin remains.
Now lay those eight segments down flat on a table
See how the middle of the segments meet up? That’s countries near the equator.
See how as you move to the top or bottom there are ever increasing gaps that need to be filled in to join the edges together?
That’s why countries are bigger in the Mercator projection.
(By the way, check out https://www.thetruesize.com for some Mercator projection fun)
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