Bitcoin is a crypto currency while the Bitcoin blockchain (example of blockchain) in it's simplest form is a database or ledger comprised of Bitcoin transaction records. However, because this database is distributed across a peer-to-peer network and is without a central authority, network participants must agree on the validity of transactions before they can be recorded.A block in a blockchain is a collection of data. The data is added to the block in blockchain, by connecting it with other blocks in chronological others creating achain of blocks linked together.