₿ Crypto & Web3 · Lesson 3 of 9 · 8 min
Ethereum & Smart Contracts
🤖 If Bitcoin is digital gold, Ethereum is digital LEGO — you can actually build things on it. Some of those things are brilliant. Some have vaporized billions of dollars. Let's learn to tell which is which.
💡 Key idea
Ethereum isn't just money — it's a platform for apps that run without middlemen.
🧠 Why it matters
Ethereum is like an app store for money. SMART CONTRACTS = code that runs automatically when conditions are met. Think: a vending machine. Insert coin → get snack. No cashier needed.
🌍 In the real world
🎮 In 2021, a digital pixel art collection called CryptoPunks sold individual images for millions of dollars. Each one tracked on Ethereum. Sounds insane — but it proved smart contracts could power entire new markets.
📌 Takeaways
- Ethereum runs apps, not just transfers
- Smart contracts = self-executing code
- Powers DeFi, NFTs, and most crypto apps
📖 Terms in this lesson
Ethereum: A blockchain that runs programs (smart contracts), not just payments.
Smart contract: A program on a blockchain that carries out a deal automatically when its conditions are met.
✅ Test yourself
What's the main difference between Bitcoin and Ethereum?
- Ethereum is faster Bitcoin
- Ethereum can run programs (smart contracts)
- Bitcoin is decentralized, Ethereum isn't
- There's no difference
Answer: B · Ethereum can run programs (smart contracts)
Bitcoin moves money. Ethereum runs programs. That's why apps, NFTs, and DeFi all live on Ethereum, not Bitcoin.
What is a smart contract?
- A legal document
- Code that automatically executes when conditions are met
- A type of cryptocurrency
- A contract between miners
Answer: B · Code that automatically executes when conditions are met
Think of a vending machine: insert money → drop snack. Smart contracts work the same way but for any digital agreement — no human needed.
Which of these typically runs on Ethereum?
- NFTs
- DeFi apps like Uniswap
- Stablecoins like USDC
- All of the above
Answer: D · All of the above
Ethereum is the most popular platform for NFTs, DeFi protocols, and many stablecoins — they all need smart contracts.
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