Week 6 — Bitcoin, Ethereum & Networks

The two dominant blockchains, what makes them different, and how the network agrees.

Week 6 of 52 · ~7 hours · 13 slides · exam + project

📖 Study these courses this week

Complete these two courses, then do the Deep Dive below, pass the exam, and finish the project.

📚 Bitcoin Deep DiveUTXOs, block time, halving, supply cap, and the genesis block story.16 slides 📚 Ethereum Deep DiveSmart contracts, EVM, gas, and why Ethereum is the world computer.16 slides

The Two Giants

Bitcoin optimizes for money; Ethereum optimizes for programmability.

What you will learn

Compare Bitcoin and Ethereum's purposes
Explain nodes, full nodes, and validation
Understand why decentralization matters

Inside a block

Keys and custody

Bitcoin: digital gold

Bitcoin was designed for one job — to be sound, censorship-resistant money. Its scripting language is deliberately limited, its supply is hard-capped at 21 million, and change is slow and conservative. That inflexibility is a feature: it preserves monetary credibility.

Ethereum: a world computer

Ethereum generalizes the blockchain into a programmable platform. Smart contracts — code that runs exactly as written — let developers build apps (DeFi, NFTs, DAOs) on top. The tradeoff: a richer attack surface and faster evolution.

💡 Two different animals

Bitcoin is like gold in a vault: boring, scarce, secure. Ethereum is like a programmable financial district: you can build almost anything, but more complexity means more that can break. Understanding which you're using matters for how you think about risk.

Nodes & validation

A node stores the blockchain and validates every transaction and block against the rules. Full nodes keep the entire history and independently verify — they don't trust, they check. A healthy network has thousands of independent full nodes enforcing consensus.

Why decentralization matters

Centralization is efficient but fragile: one point of failure, one point of control. Decentralization spreads power so no single party can censor, freeze, or rewrite. The cost is slower throughput — a deliberate tradeoff for resilience.

💡 Run your own node

Running a full node means you never have to trust a third party's copy of the truth — you verify the chain yourself. This is the purest form of 'don't trust, verify' and the foundation of self-custody.

❓ Quick check

Bitcoin's scripting language is deliberately limited in order to:

A) Save space

B) Minimize attack surface and preserve security

C) Make apps easier

D) Speed up blocks

(Knowledge check — full exam is next)

Key takeaways

Bitcoin = scarce sound money; Ethereum = programmable platform
Full nodes verify independently — 'don't trust, verify'
Decentralization trades speed for resilience and censorship-resistance

📝 Weekly Exam — pass with 80% to unlock next week

10 questions. Review the Deep Dive and courses before attempting.

1. Bitcoin's primary design goal is:

Bitcoin is optimized as money.

2. Ethereum's defining feature is:

Smart contracts make Ethereum a platform.

3. A full node:

Full nodes verify everything themselves.

4. 'Don't trust, verify' means:

Run your own node / verify signatures yourself.

5. A key cost of decentralization is:

Spreading power costs speed and adds complexity.

6. A node and a wallet differ because:

Nodes validate; wallets hold keys and sign.

7. Bitcoin's 21M cap provides:

Hard cap = predictable, deflationary supply.

8. A smart contract is:

Self-executing code on the blockchain.

9. More complexity on Ethereum means:

Richer functionality → more that can go wrong.

10. The best self-custody practice is:

Self-custody = you control the keys.

Your score: —

🛠 Weekly Project

Compare Bitcoin vs Ethereum across five dimensions.

Make a table with rows: Purpose, Supply, Consensus, Speed, Programmability.

Fill in both columns from the Deep Dive and your courses.

Write 2 sentences: which would you use as money, and which to build an app on — and why.

Open tool →

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