Chapter 2: Wave functions and uncertainty

Interference patterns

The discovery of particles acting like waves led to several experiments that produced counterintuitive results. This chapter will look at what was found and how wave functions explain what happened. We will start with the double slit experiment.

The double slit experiment was repeated using by firing electrons at two very narrow slits and recording where they hit a screen. the results showed the wave pattern expected from electrons behaving as waves.

The next step was to fire the electrons one at a time – the result was the same interference pattern.

This is surprising! How can one electron traveling on its own know about both slits and produce the interference pattern? To answer that we will need to look at the probabilistic world and wave functions.