Today's practical session will be about having a practical overview over the blockchain. We will use Elrond, Ethereum and Bitcoin as examples.

We will use Elrond, Ethereum and Bitcoin as examples. We will inspect each blockchain explorer and see how each participant interacts with the blockchain.

A blockchain Explorer is a software for visualizing blocks, transactions, and blockchain network metrics (e.g., average transaction fees, hashrates, block size, block difficulty).

Whereas under proof-of-work, the timing of blocks is determined by the mining difficulty, in proof-of-stake, the tempo is fixed. Time in proof-of-stake:

• Elrond is divided into rounds (6 seconds) and epochs (24 hours);
• Ethereum is divided into slots (12 seconds) and epochs (32 slots).

Elrond has been a Proof of Stake blockchain since its inception and uses an Adaptive State Sharding technology.

Go to Elrond's explorer Link. Browser the explorer to see:

• Blockchain metrics
• Blocks
• Transactions in the blocks
• Proposer/Leader
• Consensus Group (number of participants and the actual participants)
• Leader: Latest Consensus Round
• Validators
• Observers

Ethereum Mainnet uses proof-of-stake, but this wasn't always the case. The upgrade from the original proof-of-work mechanism to proof-of-stake was called The Merge (you can search online more about this).

Go to Ethereum's explorer Link.

Browser the explorer to see:

• Blockchain metrics
• Blocks
• Transactions in the blocks
• Proposer/Leader
• Consensus Group (number of participants and the actual participants)
• Leader: Latest Consensus Round
• Validators
• Observers

Bitcoin uses proof-of-work. The proof-of-work algorithm used by Bitcoin aims to add a new block every 10 minutes. To do that, it adjusts the difficulty of mining Bitcoin depending on how quickly miners are adding blocks. If mining is happening too quickly, the hash computations get harder. If it's going too slowly, they get easier.

Go to Bitcoin's explorers here or here.

Browser the explorer to see:

• Blockchain metrics
• Blocks
• Transactions in the blocks
• Proposer/Leader
• Consensus Group (number of participants and the actual participants)
• Leader: Latest Consensus Round
• Validators
• Observers