What are hidden variables?

Hidden variables are things that affect something else but aren’t obvious at first.

Imagine you have a toy box full of marbles, some red, some blue. You can't see inside the box, but every time you pick out a marble, it's always red. At first, you might think all the marbles are red. But maybe there’s something hidden inside the box that makes only red marbles come out, like a special divider that keeps the blue ones away.

Think of hidden variables as secret helpers in a game. You're playing with your friend, and every time you flip a coin, it lands on heads. You might think the coin is magic, but really, there’s a hidden helper, maybe your friend sneaks a little push to make sure it always lands on heads.

In real life, scientists sometimes use hidden variables to explain things that seem random or mysterious. For example, if you always get a red marble every time you pick one, there might be something hidden, like a divider in the box, that makes sure only red marbles come out. Scientists look for these hidden helpers when they’re trying to understand how the world works!