🔌 Why do electric cars need electricity helpers?

On this road, some of the cars around us might be electric cars. An electric car doesn't use gas. It runs on a big battery tucked under the floor. And it fills that battery at a charger, a special post with a cord. So why can't it just plug into the wall like a lamp? Let's follow one little electric car.

Its battery was almost empty, so it rolled up to a charger. But there was a problem. The electricity in the wires is a wiggly kind. It rushes back and forth, like a kid on a swing. A car battery can only take a smooth kind that goes one way, like water down a slide. So somebody has to change the wiggly kind into the smooth kind.

On a slow charger, the car does the changing itself, with a little helper machine hidden inside. On a fast charger, the big post does the changing, then sends smooth electricity straight in. The car just sits there, like a kid getting its shoes tied for it. Keep watch for a post with a cord out your window. Soon our little car was full and zoomed away. And every charger we pass is a helper, changing electricity so cars can go.