# Prove that the randomness of the spins of entangled quantum particles is not due to periodic factors?

I just learnt about entangled particles in a lecture today. According to the theory, the probability of the spin of an entangled particle is 50/50 (spin up or down), and is only determined when observed. This concept in quantum theory has always intruigued me.

Having just taken a programming/computing course, I remembered that I had just made a simple random number generator that could create random numbers solely by applying basic arithmatic operations to the current time. The result was always "totally random", and all ways gave 50/50 +-1% chances when simulating a coin toss.

But what intruigues me is that it wasn't random. It basically had 1 input (time), and an algorithm would spit out an output. If the same time was put into the algorithm, the output will be the same. However, it appeared to be totally random.

My question is: How can it be proven that there is not a periodicity (time) factor that determines whether a quantum entangled particle will be spin up/down when observed?

We also know that periodicity does exist in nature, such as the frequency of light waves, and this determines its properties. My teacher said that as far as he knew, it was random.