Just as "Millie, micro, nano, and pico" are Millie’s magic words to shrink smaller and smaller, "Psi" and "Collapse" are the electron’s special words for switching between its wave and particle forms.

If you’ve read the article Millie, micro, nano, and pico, you already know these words are associated with progressively smaller quantities.

In a similar way, "Psi" and "Collapse" are tied to the electron’s probability wave. This wave, known as the wave function, describes the likelihood of finding an electron in a particular spot. Some locations are more likely than others, which is why scientists use the wave function to predict where an electron might be.

The Greek letter Ψ (pronounced "psi") is used to represent this wave function. When the electron “shouts” Psi, it becomes a wave.

When the electron “shouts” Collapse, it becomes a particle. This happens because the wave function undergoes a process called collapse, where it vanishes, leaving the electron in a single, well-defined position.