Mercury coulometer

A mercury coulometer is a scientific tool that helps people measure the amount of electricity that flows through a material. Imagine you have a toy car with a battery inside. When you turn it on, the battery sends electricity to the motor, which makes the car move.

Now, let's say you want to know exactly how much electricity passed from the battery to the motor. You could use a mercury coulometer to do this.

A mercury coulometer works by measuring how much mercury (a shiny liquid metal) moves between two containers. The first container, called the anode, has a tiny hole at the bottom that lets a small amount of mercury through. This mercury flows into the second container, called the cathode, which also has a hole at the bottom. But the cathode's hole is smaller, so the mercury flows out slower than it flowed in.

If you put an electric current through the mercury, the speed at which it flows out of the cathode will change. By measuring this change, scientists can figure out exactly how much electricity passed through the mercury.

So, in essence, a mercury coulometer is like a little game where you see how much mercury can move from one container to another. But instead of just being a game, it's a really useful tool that helps scientists understand electricity better.