Dear Angel,

I’ve never sat on a power line. I like to keep my paws firmly on the ground. But birds love resting there, especially in winter. Power lines give off a little heat, so it’s a good spot for birds to snuggle together and stay warm.

I talked about how they do that safely with my friend Javier Guerrero. He’s a professor of electrical and computer engineering at Washington State University.

He told me birds do get electrocuted on power lines sometimes. But that won’t happen if the bird touches just the power line—and doesn’t touch other lines or the pole at the same time.

Power lines carry electricity. To understand how this works, we have to talk about atoms. Everything in the world is made of atoms. The air, the water, the bird sitting on the power line. Even you and me. Atoms are the basic building blocks for everything.

Atoms are made of three kinds of particles: protons, neutrons and electrons. The protons and neutrons stick together in the middle of the atom. The electrons float around the outside of the atom. Electrons closer to the middle stick to the atom. But electrons farther away aren’t as stuck. They can be pulled off.

Power plants use magnets to pull off electrons and send them through power lines. They flow down the power line to people’s homes. That’s electricity.

There are also electrons in the ground.

“The electrons in the power line and the electrons in the ground want to get together,” Guerrero said. “But that’s not possible unless you provide a path for them to get together. Anything you put between the power line and the ground provides a path for them to hang out.”

The big poles that hold up power lines are buried deep in the ground. If that pole touched the power line, it could be a path for electrons to get together.

But power companies stop the pole from touching the power line by installing insulators. They’re made of glass or plastic or some other material that electrons can’t move through easily. They cut off the path, so the electrons don’t move.

That’s why a bird can safely stand on the power line. All the electrons stay in the power line and out of the bird’s body.

But if a bird stretches its wings and touches the pole and the power line at the same time, it makes a connection between the pole and the power line. The electrons will flow through the bird’s body—also known as electrocution.

That doesn’t happen very often because power companies design their equipment to minimize accidents. Sometimes they even build nesting platforms to give birds a safe, cozy spot away from any electrical danger.

Because unsafe power lines are for the birds.


Dr. Universe