← All lessons
Crypto Lesson 4 of 7

Ethereum & smart contracts

Beyond money — programmable blockchains, smart contracts, and what they enable.

If Bitcoin is digital money, Ethereum asked a bigger question: what if the blockchain could run programs, not just record payments? That idea opened up — and complicated — the whole space.

A programmable blockchain

Ethereum is a blockchain designed to run smart contractsself-executing programs stored on the chain that run automatically when their conditions are met, with no central operator. Its native coin, Ether (ETH), pays the fees (“gas”) to run them.

A smart contract is like a vending machine in code: put in the right input, and it reliably delivers the output — no human, bank, or company in the middle.

What they enable

Smart contracts power most of what people mean by “crypto beyond Bitcoin”:

This is the genuinely innovative frontier — and also where the most hype, speculation, and outright scams concentrate.

The risks are different — and sharp

Smart contracts run exactly as written, bugs included. If the code has a flaw, attackers can drain it — and there’s often no one to refund you and no “undo”. Hundreds of millions have been lost to contract exploits, rug-pulls (developers vanishing with funds), and exploitative tokens. The more complex and “high-yield” something sounds in DeFi, the more carefully you should assume the risk is real.

The takeaway

Ethereum is a programmable blockchain running smart contracts — self-executing code that powers DeFi, tokens, and NFTs without a central operator. It’s the innovative edge of crypto, but contracts run as written (bugs and all), so exploits and scams are common and usually irreversible. (This is education, not investment advice.)

Finished this lesson? Mark it complete to bank +10 XP and keep your streak alive.

Educational content — not yet expert-reviewed. This is education, not financial advice.

Back to all lessons
Nice! +10 XP 🎉