Unlike real life, the internet has everything in abundance. If you like a photo, you can download it and share it with your friends. If you like a movie, you often torrent it. Now apply this concept to money. If our money is completely digital, anyone could copy and paste it multiple times to get rich overnight. But if everyone starts doing this, it will make no sense whatsoever. Therefore, double spending can be defined as the problem of spending the same money twice by cloning it. Bitcoin solves this problem by waiting for confirmations after the block has been created. This usually takes 60 minutes, after which the transaction becomes immutable.