Overview of some simple map projections

Some lists of map projections cover them in a way that I think is more haphazard than it needs to be. This is my attempt at a simple introduction to some map projections. I'll only look at the usual situation, in which we are mapping the surface of a sphere onto a planar map. The …

Daylight Saving Time

Public opinion seems to be turning against Daylight Saving Time (DST), despite the fact that most of our clocks now change automatically, and despite the fact that most people don't even seem to have a clear understanding of what DST does, and what its purpose is. I'm not necessarily the biggest proponent of DST, but …

The northernmost and southernmost trees

Where are the northernmost and southernmost naturally-growing trees in the world? I thought it would be easy to find the answer, but it turn out, not so much. Northernmost The northernmost trees are most certainly Dahurian larch (Larix gmelinii) trees growing in north central Russia. They are apparently somewhere in the marked region below, or …

How to walk around the Earth

Suppose we start at Cape Horn, at the southern tip of South America. We are challenged to travel from there to Tasmania (the big island south of Australia). We can travel freely over land, but only for X consecutive kilometers over water. How small can X be, and still allow us to reach Tasmania? Ground …