Learn Ethereum: Blocks

Task 1: Register

If you haven’t already, register for this cohort by joining our Discord.

Task 2: Vocabulary

Prepare by familiarizing yourself with these key terms. I’ve broken them down into simple analogies to help you out! Be sure to take the quiz at the end when you are ready.

Key Terms

1. Block: Batches of transactions with a hash of the previous block in the chain.
   Analogy: It’s like adding a sealed page to a journal where each page has a reference to the previous one, creating a secure link.

2. Validator: A node on a blockchain network responsible for verifying transactions and creating new blocks.
   Analogy: A validator is like a gatekeeper who checks each ticket at a concert and decides who gets in, ensuring no one cheats the system.

3. Proof-of-Stake (PoS): Consensus mechanism used in blockchain networks that rewards participants based on the amount of cryptocurrency they stake.
   Analogy: Think of it like a raffle where your chances of winning increase with how many tickets (crypto) you’ve bought (staked).

4. Slots: 12-second units of time separating the creation of blocks by a validator.
   Analogy: It’s like scheduled bus stops where each bus (block) must leave every 12 seconds, keeping everything moving smoothly.

Task 3**.1: Overview of reading**

Here is an overview of the reading for this lesson. Don’t get too worried if you don’t understand all of it yet. We will be diving deeper in week 4. For the section titled ‘What’s in a Block’, there is no need to memorize this. However, it is a good idea to get the gist of it.

How blocks work

Blocks are like containers for transactions, and they follow a strict order. Each block has a reference to the previous block, forming a chain. Validators create new blocks and broadcast them to the network. All nodes then add the new block to the chain and select the next validator to continue the process. The proof-of-stake (PoS) consensus mechanism ensures agreement on which blocks are valid.

Proof-of-Stake

Validators, who stake 32 ETH, are randomly chosen to propose blocks. They bundle transactions, execute them, and suggest new "state" changes. Other validators verify these changes by re-executing transactions to maintain security. If there’s a conflict between two blocks, validators use a rule (fork-choice algorithm) to choose the one with the most support.

Block Size

Blocks have a gas limit to control their size, ensuring no block becomes too big to process quickly. Larger blocks require more computing power, which can centralize control. Validators can adjust the gas limit slightly over time based on network activity. Keeping block sizes manageable is essential to maintaining the network's decentralization.

Task 3.2: Read the docs

Read the official "Blocks" section here.

After reading, you can take this comprehension quiz to test your understanding.

Task 4: Answer Discussion Questions

Now, it’s time to talk about what we’ve learned. You can answer the discussion questions here.

1. Why are transactions batched into blocks?

2. How would you describe the proof-of-stake protocol?

3. Why is block size important?