Lesson 02 10 min read

How Does
Blockchain Work?

A simple explanation using a shared Google Sheet that no one can secretly change.

Progress: 2 of 15

The Best Analogy: A Shared Google Sheet

Imagine a Google Sheet that records every transaction. This sheet is shared with thousands of people around the world.

  • Anyone can see the entire sheet (transparent)
  • No one can delete or secretly edit old entries (permanent)
  • When someone adds a new row, everyone gets an updated copy

This shared, permanent, transparent Google Sheet is basically what a blockchain is.

How a Transaction Works (Step by Step)

1

You want to send money

You open your wallet and enter the amount and the recipient’s address.

2

The transaction is broadcasted

Your wallet sends the request to the network with your digital signature.

3

Validators check it

Thousands of computers verify you have the coins and haven’t double-spent them.

4

The block is added

Verified transactions are grouped into a block and added permanently to the chain.

How Blocks Are Linked

Block #124,892
000000a3f8...
Block #124,893
000000b7c2...
Contains previous block’s hash

Each block contains the hash of the previous one — creating an unbreakable chain.

Key Takeaway

Blockchain is a transparent, permanent, and decentralized digital ledger. It removes the need to trust any middleman because the rules are enforced by mathematics and thousands of independent computers.

Quick Summary

  • Blockchain = shared, unchangeable ledger
  • Every transaction is verified by the network
  • Blocks are linked using cryptography
  • No single person or company controls it
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Bitcoin in 2026
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