ELI5: Explain Like I'm 5

Quantum indeterminacy

Quantum indeterminacy is when particles in the world of quantum physics behave differently than you would expect. It means that you can't predict exactly what will happen when you look at a single particle like an electron. Instead, you can only predict the probability of what will happen. That means that the particles don't always follow the same path and sometimes act randomly. In other words, the future of these particles can't be determined completely.