There was lightning in your kitchen today. Did you see? Premium

A teacher at IIT Kanpur explains how a gas stove lighter works and what the piezoelectric effect is.

My mornings in IIT Kanpur, where I teach, are interspersed with sips of green tea, the longing calls of peacocks and peahens, and the purposeless barking of my neighbour’s dog. Often making things interesting is a mess in the kitchen – the result of my tendency to ignore the milk I left on the stove, and remember it just as it boils, flows over the vessel, spills on the counter, and drools to the floor.

As I curse the milk, I also can’t help but feel some sympathy for the innocent victim of this mess: my stove-lighter. Resting there in innocence on the counter, it has no idea that it is having a bad day.

These lighters are magical pieces of equipment. A push with your thumb, something clicks, and there comes a flame. If you haven’t noticed it, go to your kitchen, pick up the lighter, point it towards yourself, and watch carefully. As you click it, you will notice a small spark flying between the central rod and the cylindrical covering. But don’t worry: unless you are flammable (regular human beings are not), there is no danger of you catching fire or even getting an electric shock.

This same spark accompanies the wonderful monsoons (which we eagerly await in Kanpur), just that they screech through the night sky and can add amazing percussions to a late night instrumental on the stereo.

What is it, then, that allows that small piece of equipment to create thunder in your kitchen, and at the innocuous push of your thumb?

To understand this, we first need to figure out what an electric spark is.

A spark is essentially an electric charge flying in the air between two points, one of which has a large quantity of surplus electrons while the other has too few. This difference in quantities of electrons can happen due to many reasons. Sometimes people have engineered it this way using chemicals: the simplest example is the battery that we use in everything from remote-controls to electric vehicles.