How transactions are verified in Bitcoin Blockchain - Longest chain rule explained?

Bitcoin Blockchain is like a group of kids passing notes in class, and everyone agrees on what’s written to keep things fair.

Transactions are like notes saying “John gave Sarah 2 candies.” When someone sends Bitcoin, they write this note and pass it around the class. But there might be more than one version of the same note, maybe John wrote two different notes at once! That's where the longest chain rule comes in.

Imagine each kid in class keeps track of all the notes they’ve seen. When a new note arrives, they add it to their list. But if someone gets a longer list, with more notes, they know that’s the most up-to-date version of what happened. They switch to using that longer list because it shows the most recent and agreed-upon transactions.

This is like when you're playing a game and someone shouts out the latest score. If everyone agrees, they all update their scoreboard to match. The longest chain is just the most trusted version of the whole story so far, no need for magic, just kids passing notes and picking the most recent one!