How can birds perch on electricity cables without getting electricuted?
Electricity flows from a higher potential to a lower one. If you connect your hand to the live terminal of a domestic mains circuit while standing with bare feet on damp ground, your hand will be at a potential of 230V while your feet will be ‘earthed’ (i.e. at a potential of 0V). So electricity will flow from your hand to your foot. If however you were to connect both your hands and feet to live mains terminals, while standing on an insulated surface, no electricity would flow because there would be the same potential (230V) present at the ends of both your upper and lower limbs (and, indeed, throughout your body).. If a bird sits on an electricity cable, there will be a potential of, say, 25000V at its feet (and throughout its body) but since no part of its body is earthed (or otherwise at a lower potential), no electricity can flow. A tight-rope walker (using an insulated pole for balancing) could walk along the cable with the same immunity from electrocution. (Once again, the whole
