Category Archives: Electricity

Lightning and the Earth’s Electric Field

A photograph showing some spectacular lightning bolts above a city skyline at night.Earth’s Electric Field

The Earth has an electric field.  On average, this field points vertically downwards and it has a magnitude of about 100 N C-1 (Newtons per Coulomb).  It exists because the Earth’s surface carries a negative charge of – 5 x 10C, while the upper atmosphere carries a compensating positive charge.  An average of 400,000 thunderstorms a day  Continue reading Lightning and the Earth’s Electric Field

Let There Be Light…

A photograph showing the sun reflecting over the waters at Loch Kathrine through a curtain of trees. Low sun. Image: NaturPhilosophieFiat Lux…

Light.  Most of us take it for granted during the day.  And at night, we have learned to domesticate it.  Light, the natural agent that stimulates our sense of sight and makes things around us visible.  Continue reading Let There Be Light…