How Do Trees Know When It’s Spring
How Do Trees Know When It’s Spring? Broadleaf trees have to work out the best time to come into leaf each year, they need to…
Tag: clocks
How to Use the UK Military’s Survival Compass to Tell the Time
A guest blog by John Hudson FRGS, the UK military’s Chief Survival Instructor. Direction finding in the military these days uses lots of technology, but…
Why does the Gnomon on a Sundial Point South?
The pointy bit of a sundial is called a ‘gnomon’. It is the part that casts the shadow and in the northern hemisphere it points…
How to Build the World’s Simplest Sundial
My thanks to Vincent Alaniz for sending me this photo and a question, which I will answer here. Whenever we consider the position of the…
Analemmas and the Equation of Time
If you stood on the same spot and took a photo of the sun every day during a year’s worth of good weather, at exactly…