The way a Faraday cage blocks a lightning strike

Think of a lightning bolt as a rogue bull charging across the scrub. If you’re inside a metal cage—like a sturdy ute—that bolt doesn't want to go through you. It’s looking for the fastest track to the dirt, and metal is a wide-open highway.

Electrons in the metal skin scramble to the outside edge instantly, creating a shield that cancels the zap. Inside, the air stays as calm as a billabong.

The sky-fire just slides around the frame and dives into the ground, leaving you safe while the world outside goes white.

Hang on, why do those electrons only scramble to the outside edge?

See, electrons are like a mob of cranky steers that can't stand the sight of each other. Since they’re all negatively charged, they want as much space as possible between them.

When lightning hits, they don't huddle in the middle. They bolt for the fence line—the very edge of the metal—trying to get as far away from their mates as the frame allows.

Because they're all pushing outward, they cancel out any pull toward the center. It’s a standoff on the perimeter that keeps the inside deader than a Sunday in a ghost town.

But what if the cage has holes? Won't the lightning just squeeze through?

Think of it like a dingo trying to squeeze through a chicken-wire fence. If the gaps are small enough, that dog is staying on the outside, no matter how much he snarls.

Lightning isn't just a spark; it’s a wave of energy. If the holes in your mesh are smaller than the 'width' of that wave, the electrons treat the gaps like they aren't even there.

They keep jumping from wire to wire, patrolling the perimeter like a boundary rider on a long fence line. As long as the mesh is tight, the inside stays as dry as a bone in a drought.

Hold on, how wide is this wave of energy exactly?

That width is what the eggheads call wavelength. For a massive bolt of lightning, that wave is kilometers long, so a mesh with holes the size of a dinner plate would still look like a solid brick wall to it.

But if you’re talking about your mobile phone or a microwave, those waves are short—only a few centimeters. To stop those, you need a mesh as tight as a flyscreen on a humid night in Queensland.

It’s all about the size of the beast you’re trying to pen in. If the gaps are bigger than the wave, the energy slips through like a snake through a picket fence.

Is light just a wave that's small enough to slip through those gaps?

Spot on. Light is part of the same mob as radio waves, but it’s a pint-sized member. Its wavelength is so tiny you could fit hundreds across the sharp edge of a pocket knife.

To a light wave, those mesh holes look like a wide-open paddock gate. It sails through without brushing a wire, which is why you can see your meat pie spinning around in there.

But the microwaves are too chunky. They hit that mesh and see a solid wall, bouncing back to heat your tucker instead of leaking out and causing a mess in the kitchen.