Graduate Student Dave Fleming demonstrates how electronic ink works using the egg tray and ping pong balls.
The goal of this demonstration is to show things on a micro scale can effect what we see on a macro scale. Demonstrate that research is not just a result it's also a process.
Really tiny microcapsules the diameter of a human hair have both black and white particles in them. The white particles have a positive charge so when you put a negative charge on the top they rise up while the black molecules sink. The black particles have a negative charge and get pulled up with a positive charge run over the top. Al the micro capsules are put on a piece of plastic and laminated to sheet of circuitry. It's the circuitry that changes the polarity and moves the particles to change the color. Eventually a printer should be able to print the microcapsules on the circuitry paper and you could make anything you want.
The worst thing here is that the batteries could go dead but they should last a year.