Why can we get a shock from a car door?

HAS THIS ever happened to you?

You get out of a car, your hand touches against the metal door and zzzt, there it is, a sensation that stops you in your tracks.

You’re probably aware that the “shock” has something to do with static electricity, but how does it work?

And why might we be more likely to experience that jolting little surprise at some times more than others?

Let’s start with the “static” part: when objects or materials rub against each other, they can build up positive or negative electrical charges on their surfaces.

How does this affect you in the car? As the helpful website physics.orgpoints out, electrons can move between the materials that are rubbing together, such as your clothes and the car seat.

And ultimately the surfaces can build up static charges.

Then when you get out of the car and touch against the metal door, which is a conductor, electrons move between you and the door as the charge is suddenly neutralised. You experience it as a shock.

As for why you might get such shocks more frequently some times compared with others, the weather can have an influence.

In more humid conditions, electrons can leak away from surfaces more easily into the atmosphere, so there’s less of a build-up of static charge.

Drier air, on the other hand, can allow charges build up more, and when they go, they go in style. Ouch.