What exactly is blockchain? A blockchain is a digital record book shared across a network of computers. It records transactions in groups called blocks. Each block is linked to the previous one, creating a chain of records. Once information is added and confirmed, changing it becomes difficult because the network can detect changes to earlier records. That’s the basic idea behind blockchain. How does blockchain work? Let’s say you want to send money to someone using a blockchain network. Here’s what happens: -You initiate the transaction. -The network checks whether it follows the rules. -Valid transactions are grouped into a block. -The network confirms and adds the block to the existing chain. -The transaction becomes part of the recorded history. The exact process depends on the blockchain but that’s the general idea. Now you might be asking “who controls the records? This is one of the biggest differences between a traditional database and a public blockchain. With a bank, the bank maintains the official transaction records. With a public blockchain, multiple computers maintain and verify copies of the records according to the network’s rules. These computers are called nodes. Instead of relying entirely on one institution to maintain the record, participants can verify the same history. How does blockchain prevent people from changing transactions? Blockchain uses cryptography to connect blocks and help protect the records. Each block contains a digital fingerprint called a hash. It also includes information that links it to the previous block. If someone changes an earlier block, its fingerprint changes, disrupting that connection. The network can detect this. On a properly secured blockchain, changing confirmed records can be extremely difficult because an attacker would also have to overcome the network’s security and consensus rules. What is decentralization, and why does it matter? Decentralization means control is distributed among multiple participants rather than placed entirely in the hands of one central authority. On many public blockchains, different participants help verify transactions and maintain the network. This can reduce dependence on a single institution. However, not every blockchain is equally decentralized. Some rely more heavily on a small number of validators or operators. The level of decentralization depends on how the network is designed and managed. Where do Bitcoin and Ethereum fit into all this? $Bitcoin and $Ethereum are two well known examples of blockchain networks, but they serve different purposes. $Bitcoin was designed around a peer-to-peer electronic payment system and is widely used as a digital asset. $Ethereum allows developers to build applications that run using smart contracts. Both use blockchain technology, but they have different designs, rules, and capabilities. Understanding this difference helps you see why blockchain is bigger than just buying and selling coins.