Why can birds perch on power lines without being electrocuted?

One of my pupils asked me this interesting question: why can birds perch on power lines without being electrocuted?

Here's the scientific explanation:
Birds usually perch on a single power line. Hence, there is no potential difference between the two feet and no electric current will flow through the bird.

For the bird to be electrocuted, a potential difference must exist across its two feet. If the bird touches two power lines at a time, or one power line and a ground wire or the Earth, the bird would be electrocuted and die.

Many large birds such as eagles and vultures can be electrocuted when their wide wings touch a power line and a ground wire at the same time.

Let's watch a video that explains this phenomenon through an experiment:

A word of advice:Do not fly a kite near power lines. If the kite gets tangled in the power lines, the kite string acts as a ground and you can be electrocuted.


~ By Serena's Greenhouse