Power up! An underground hydroelectric generator powers the entire City of Ember. This week, Everyday Einstein explains the science behind the popular series.
According to the Book of the City of Ember, "The City of Ember is the only light in the dark world. Beyond Ember, the darkness goes on forever in all directions." And just what is the reason for that light? If you've read the book or seen the movie (and if you've only seen the movie I strongly recommend you forget all about it and read the book instead), you know that the source of Ember's light is an underground hydroelectric generator. So this week, let's take a look at how hydroelectric generators work, and where they're used today.;
To understand how hydroelectric generators work, we first need to understand electromagnetic induction. Back in the 1800s, a man named Michael Faraday discovered this interesting fact: If you take a conductor (like metal wire) and subject it to a fluctuating magnetic field, you can induce, or create, an electrical current in the conductor.
In a typical generator design, magnets are mounted on a disk called a rotor. This rotor spins around inside of a container (called a stator) with conductors mounted on the outside. As the rotor spin around inside the stator, the magnets continually pass the conductors, inducing electricity.