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Hard Money Diploma · Module 9: How Does Bitcoin Mining Work?

The student workbook, page for page, with the answers in red ink and yellow notes on what to anticipate. This module can feel technical: lean on analogies and diagrams, keep nodes and miners clearly separated, and let students see the system self-regulate. Reveal every ink, check every page, and you have hit everything.

Hard Money Diploma · Student WorkbookModule 09 · How Does Bitcoin Mining Work?
Guide: 8 minPlan 8

9.0 Introduction

In this section, we'll take a closer look at two very important parts (and participants) of the Bitcoin network that were first introduced in Module 5:

Bitcoin Nodes

Gatekeepers of validation whose main job is to keep a copy of the Bitcoin ledger, and to make sure that all transactions are valid and that everyone follows the same rules. By distributing this job among many people worldwide, Bitcoin stays strong against potential fraud without relying on a centralized authority. Nodes help keep the system trustworthy and true to its decentralized ethos, where no one person or group has too much power over the rest.

Bitcoin Miners

Architects of security who solve cryptographic puzzles by using powerful computers and electricity. They check and confirm transactions, making sure everything is secure. Their computational work helps make the ledger (or blockchain) resistant to any bad actor by making the alteration of the blockchain expensive in energy terms.

Together, Bitcoin nodes and miners work as a team to maintain a decentralized, secure, and strong system, a truly novel monetary system that people all around the world can rely on. Let's explore these roles in more detail to understand how they contribute to the Bitcoin protocol.

✒ TEACHER: opening the chapter by connecting to keys
  • Ask first: "If a user signs a transaction with a private key, what happens next? Who checks whether it is valid? How does it get added to the blockchain?" Let them reason before you add anything 9.0
  • Nodes are gatekeepers of validation; miners are architects of security who use computers and electricity to secure the ledger 9.0
  • Frame the whole chapter as: how the network processes transactions in practice, and how mining secures the system without a central authority
ANTICIPATE
  • Myth to expect (from the Misconceptions Library): "miners control Bitcoin." No: nodes enforce the rules; miners propose blocks and must follow those rules to be accepted.
  • Protect this framing: the whole chapter rests on Miners are not Nodes. The guide says to clarify that distinction immediately and repeat it often.
    • Teacher's Edition9.0 •
    Hard Money Diploma · Student WorkbookModule 09 · How Does Bitcoin Mining Work?
    Guide: part of 47Plan 15

    9.1 Bitcoin Nodes and Miners

    Bitcoin nodes may sound technical, but they are simply software that keeps a copy of the Bitcoin blockchain on a computer. The blockchain is a shared record of all Bitcoin transactions.

    When you run your own node, you verify Bitcoin transactions yourself instead of trusting someone else. This gives you more independence and helps keep the Bitcoin network decentralized.

    What Is a Bitcoin Node?

    You can think of a Bitcoin node as a digital traffic officer with a few important jobs.

  • It keeps a copy of the blockchain, which is the history of all Bitcoin transactions.
  • Nodes connect with other nodes around the world and share information. One example is the list of new transactions waiting to be confirmed, which is called the mempool.
  • Nodes check that every transaction follows Bitcoin's rules. If a transaction is invalid, the node rejects it.

    • Nodes also help new nodes join the network by sharing the blockchain with them. However, every new node still checks all the rules independently. Anyone can run a node by installing software such as Bitcoin Core and downloading the blockchain. Once it is set up, the node continues to receive new blocks roughly every 10 minutes and verifies them before adding them to its copy of the blockchain.

    The purpose of mining is not the creation of new bitcoin; that's the incentive system. Mining is the mechanism by which Bitcoin's security is decentralized.

    Andreas M. Antonopoulos
    💡

    Miners collect unconfirmed transactions, form a block, and use energy to find a key that adds and secures the block.

    Miners compete to add the next block of transactions to the blockchain. To do this, they must find a special number that creates a valid block hash. You can imagine it like searching for the right key among billions of possibilities. The first miner to find the correct hash wins the race and earns the right to add their block to the blockchain.

    Miners earn bitcoin in two ways

  • Block rewards: new bitcoin are created and given to the miner who successfully adds a block to the blockchain.
  • Transaction fees: when people send bitcoin, they include a small fee. The miner who adds the block receives the fees from the transactions included in that block.
    • ✒ TEACHER: the node as a digital traffic officer
    • A node keeps a copy of the blockchain, shares information with other nodes (like the mempool), and checks that every transaction follows the rules, rejecting invalid ones 9.1
    • Running your own node lets you verify transactions yourself instead of trusting someone else, which gives more independence and keeps the network decentralized 9.1
    • Anyone can run a node with software such as Bitcoin Core; each new node still checks all the rules independently 9.1
    ✒ TEACHER: what mining is actually for (the Antonopoulos point)
    • The purpose of mining is not the creation of new bitcoin; that is the incentive. Mining is the mechanism by which Bitcoin's security is decentralized 9.1
    • Miners earn in two ways: block rewards (newly created bitcoin) and transaction fees (fees attached to the transactions they include) 9.1
    ANTICIPATE
  • Myth to expect (Misconceptions Library): "miners create Bitcoin from nothing." Be precise: the new bitcoin is the incentive; the mining work is what secures the network.
  • Keep saying it: nodes validate, miners propose. The guide's own line is "referees versus players." Do not let the two roles blur on this page.
    • Teacher's Edition9.1 •
    Hard Money Diploma · Student WorkbookModule 09 · How Does Bitcoin Mining Work?
    Guide: part of 47Plan 10

    9.1 Bitcoin Halvings

    20092012201620202024
    50 BTC25 BTC12.5 BTC6.25 BTC3.125 BTC
    💡

    Miners' rewards for completing one block halve every 210,000 blocks, about every four years.

    Bitcoin has a fixed maximum supply of 21,000,000 bitcoin, but all of them were not created when Bitcoin started. Instead, new bitcoin are gradually introduced into circulation through mining. When miners successfully add a new block of transactions to the Bitcoin network, they receive a block reward in bitcoin. In the early days of Bitcoin, this reward was 50 bitcoin per block. This reward encouraged people to use computing power and electricity to help secure the network.

    About every 210,000 blocks (roughly every 4 years), the block reward is cut in half. This event is called the halving. The halving slows down the creation of new bitcoin and helps ensure that the total supply will never exceed 21 million. Over time, this makes bitcoin increasingly scarce.

    📖

    Circulating supply refers to the total available amount of a currency. With Bitcoin, the total circulating supply is the number of coins that have been mined and are in circulation at any given time.

    📖

    The Bitcoin supply schedule is the predetermined and public plan for the release of new bitcoin into circulation, designed to maintain Bitcoin's scarcity over time.

    Miners still earn transaction fees from the transactions included in the block they mine. Over time, these fees are expected to become a larger part of miners' income. Halvings are built into the Bitcoin protocol and happen automatically about every four years. Because of this, Bitcoin's supply schedule is predictable and transparent.

    EventDateBlockRewardMined
    5th Halving20281,050,0001.5625 BTC98.44 %
    6th Halving20321,260,0000.78125 BTC99.22 %
    7th Halving20361,470,0000.390625 BTC99.61 %

    As more bitcoin are mined, the circulating supply keeps increasing until the maximum supply of 21,000,000 bitcoins is reached, which is expected around the year 2140. Because fewer new bitcoins are created over time, if demand increases, the price of Bitcoin can rise. This also encourages miners to keep securing the network by contributing their computing power.

    ✒ TEACHER: the halving in one line
    • About every 210,000 blocks (roughly every 4 years), the block reward is cut in half; this is the halving 9.1
    • The halving slows the creation of new bitcoin and helps ensure the total supply never exceeds 21 million, making bitcoin increasingly scarce 9.1
    ✒ TEACHER: a fixed, predictable supply
    • The supply schedule is a predetermined, public plan for releasing new bitcoin, designed to maintain scarcity over time 9.1
    • Halvings are built into the protocol and happen automatically, so the schedule is predictable and transparent; the max of 21 million is expected around 2140 9.1
    • Use the table to show issuance winding down; over time, transaction fees are expected to become a larger part of miners' income
    ANTICIPATE
  • Myth to expect (Misconceptions Library): "miners create Bitcoin from nothing." Ground it in real numbers: 50 to 25 to 12.5 to 6.25 to 3.125 BTC. Issuance is on a fixed, shrinking schedule, not printed at will.
  • Someone may ask "what happens when all 21 million are mined?" Point to fees: miners still earn transaction fees, expected to become a larger share of their income over time.
    • Teacher's Edition9.1 •
    Hard Money Diploma · Student WorkbookModule 09 · How Does Bitcoin Mining Work?
    Guide: part of 47 · core of the chapterPlan 22

    9.1 Proof of Work and Difficulty

    What is a valid block hash in Bitcoin?

    In Bitcoin, miners compete to find a special code called a block hash. This code identifies a block of transactions and allows it to be added to the blockchain. Each block contains information about recent transactions and also includes the hash of the previous block. This links every block together, forming a chain from the very first block (the Genesis Block) to the most recent one.

    A hash works like a digital fingerprint for the data in the block. If any information in the block were changed, the fingerprint would change as well. This makes it easy for anyone to verify that the blockchain's transaction history has not been altered and helps keep the network secure.

    💡

    Satoshi Nakamoto, the creator of Bitcoin, mined the Genesis Block, which unlocked a total of 50 bitcoin.

    The Race to Mine a Block

    Miners compete to find a valid block hash. The first miner to find one gets to add the new block to the blockchain and receive a bitcoin reward. To be valid, the block's hash must be lower than a number set by the network called the difficulty target. Because hashes are random, miners must keep trying different inputs until they find one that works.

    If too many miners are competing, blocks would be found too quickly. If too few miners are participating, blocks would take too long to find. To keep the system running smoothly, Bitcoin automatically adjusts the difficulty every 2,016 blocks (about every two weeks). This adjustment ensures that, on average, a new block is added to the blockchain about every 10 minutes.

    📖

    The difficulty level in Bitcoin mining measures how hard it is to find a valid block hash. The network adjusts this difficulty every 2,016 blocks (about every two weeks) so that new blocks are added about every 10 minutes. The higher the difficulty, the harder it is for miners to find a valid block.

    By finding a valid block hash, a miner proves they have done the work required to add a new block to the blockchain. This process is called Proof of Work (PoW). It is the security mechanism that allows Bitcoin to confirm transactions and add new blocks to the blockchain. Proof of Work helps keep Bitcoin secure by making it extremely expensive for anyone to try to cheat or take control of the network. Instead, it is far more profitable to follow the rules.

    Miners play four main roles

  • Collect transactions: miners choose transactions that have been sent to the network and place them into a candidate block.
  • Perform Proof of Work: miners compete to solve a difficult mathematical puzzle by finding a valid block hash.
  • Broadcast the block: the first miner to find a valid solution shares the new block with the network.
  • Earn rewards: if the block is valid, it is added to the blockchain and the miner receives newly created bitcoin plus transaction fees.
    • ✒ TEACHER: what a valid block hash is
    • A hash is a digital fingerprint for the block's data; change any information and the fingerprint changes, so anyone can verify the history has not been altered 9.1
    • Each block includes the hash of the previous block, linking every block into a chain from the Genesis Block to the most recent one 9.1
    ✒ TEACHER: Proof of Work, what it proves
    • By finding a valid block hash, a miner proves they did the work required to add a block; this is Proof of Work 9.1
    • PoW secures Bitcoin by making it extremely expensive to cheat or take control, so it is far more profitable to follow the rules 9.1
    • A strong teaching line: Proof of Work makes dishonesty expensive and verification easy
    ✒ TEACHER: difficulty adjustment (the self-regulating part)
    • To be valid, a block's hash must be lower than the network's difficulty target; hashes are random, so miners keep trying inputs until one works 9.1
    • Bitcoin adjusts difficulty every 2,016 blocks (about every two weeks) to keep the average block time near 10 minutes 9.1
    • More hash power means difficulty rises; less hash power means it falls. The guide's line: "the system breathes" 9.1
    ANTICIPATE
  • Protect this page. The guide calls this section the core of the chapter and lists Proof of Work and difficulty adjustment among the top priorities if time runs short.
  • Myth to expect (Misconceptions Library): "more mining = less secure." The opposite: more honest hash power raises the cost of an attack. Difficulty simply re-targets to keep blocks near 10 minutes.
  • Myth to expect: "Proof of Work is just wasteful." The guide's reframe: expensive security prevents attacks and makes them pointless.
    • Teacher's Edition9.1 •
    Hard Money Diploma · Student WorkbookModule 09 · How Does Bitcoin Mining Work?
    Guide: 15 minPlan 15Mempool activity not budgeted separately

    9.2 What Is the Mempool?

    The mempool, short for "memory pool," is like a waiting room for Bitcoin transactions. When you send bitcoin, your transaction is first broadcast to the network and placed in the mempool.

    You can think of it like waiting in line at a restaurant. Your name goes on a list, and you wait until a table is available. In the same way, your transaction waits in the mempool until a miner includes it in a block.

    Bitcoin nodes check each new transaction to make sure it is valid and that the bitcoin being spent has not already been used. If the transaction is valid, it stays in the mempool until it is confirmed. Miners choose transactions from the mempool and include them in new blocks. Usually, transactions with higher fees are chosen first. Once a transaction is included in a block, it becomes confirmed and is permanently recorded on the Bitcoin blockchain.

    Activity: Exploring the Mempool

    This activity exposes students to a free and open-source tool that does not require technical skills to use. It is useful for Bitcoiners at all levels, from beginner to experienced. (Resource card: qr.myfirstbitcoin.org/mempool.pdf)

    Key Points

  • Mempool refers to the list of unconfirmed transactions maintained by each Bitcoin node, not a specific service or platform.
  • There is no single, universal mempool. Mempool.space is one of many.
  • Mempool.space is open-sourced and well known for being an easy-to-use visual block explorer. It provides real time data on unconfirmed transactions, fee rates, and other network activity.
    • 💡

    Student Tip: Mempool.space does much more than visualize blocks. Explore other parts of the Bitcoin ecosystem, for example Lightning, mining, the hash rate, pools, and block space "goggles."

    ✒ TEACHER: the mempool as a waiting room
    • The mempool is a waiting room for valid, unconfirmed transactions; nodes verify a transaction first, then it waits until a miner includes it in a block 9.2
    • Use the restaurant line image: your name goes on a list and you wait until a table is available 9.2
    ✒ TEACHER: fees, and "not one universal mempool"
    • Miners usually choose higher-fee transactions first, so higher fees are more likely to be confirmed sooner 9.2
    • Each node maintains its own mempool; there is no single, universal mempool. Mempool.space is one explorer of many, not the mempool itself 9.2
    ANTICIPATE
  • Myth to expect: "the mempool is the blockchain." No: it holds unconfirmed transactions only; nothing there is final until it is in a block.
  • Timing gap: the guide lists "Exploring the Mempool" as an Activity but budgets no separate minutes for it inside the 15-minute block. If you run it live on mempool.space, reserve real time and trim elsewhere.
    • Teacher's Edition9.2 •
    Hard Money Diploma · Student WorkbookModule 09 · How Does Bitcoin Mining Work?
    Guide: 20 minPlan 20

    9.3 How Transactions Work

    Now that you understand public and private keys, as well as the roles of nodes and miners, here's how a Bitcoin transaction works from start to finish.

  • Adam wants to send bitcoin to Gerardo. He creates a transaction with Gerardo's address, the amount to send, and a fee.
  • Adam signs the transaction with his private key to prove ownership.
  • He broadcasts the transaction to the Bitcoin network.
  • Nodes receive it and check that it follows the rules, including verifying the signature and that Adam has enough bitcoin.
  • If valid, the transaction is shared across the network and added to the mempool, where pending transactions wait.
  • Miners pick transactions from the mempool and include them in a block they try to mine.
  • When a miner successfully mines a block, it is shared with the network and checked by other nodes.
  • If valid, the block is added to the blockchain. Gerardo receives the bitcoin.
  • As more blocks are added, the transaction gains confirmations, making it more secure.

    • Once included in a block, the transaction is confirmed. Adam cannot spend that bitcoin again, and Gerardo can spend what he received in a new transaction.

    📖

    Transaction and fee selected, signed by wallet and sent, distributed by nodes, miner adds transaction to block template, miner wins Proof-of-Work contest, new block is validated, new block is distributed by nodes.

    Resource: a walkthrough video is linked on the student page (youtube.com/watch?v=xc_TxlByxeY).

    Wrap-Up and Check for Understanding

  • What is the difference between a node and a miner?
  • What is the mempool?
  • Why do some transactions confirm faster than others?
  • What does Proof of Work prove?
  • Why does Bitcoin adjust mining difficulty?
  • What are the main steps between sending a transaction and receiving confirmation?
    • ✒ TEACHER: walking the full lifecycle
    • Create the transaction (address, amount, fee), sign it with the private key, broadcast it; nodes verify and add it to the mempool 9.3
    • Miners pick it into a candidate block and compete through Proof of Work; the winner broadcasts the block, nodes verify it, and it is added to the blockchain 9.3
    • Once in a valid block the transaction is confirmed: the spent inputs cannot be reused, and the receiver can now spend what they received. More blocks means more confirmations 9.3
    ✒ TEACHER: wrap-up answers
    • Node vs miner: nodes validate and store the ledger; miners propose new blocks and compete through Proof of Work. Referees versus players 9.1
    • The mempool is the waiting room of valid, unconfirmed transactions 9.2
    • Transactions with higher fees are usually chosen first, so they confirm faster 9.2
    • Proof of Work proves a miner spent real computation and energy, which makes attacking the ledger expensive 9.1
    • Difficulty adjusts every 2,016 blocks to keep the average block time near 10 minutes 9.1
    ANTICIPATE
  • Protect this page. Transaction flow from signing to confirmation is on the guide's short-on-time priority list. Use one clear diagram and pause after each stage.
  • Myth to expect: "once I hit send, it's instant and final." No: it waits in the mempool, then gains security as confirmations stack up.
  • Bridge line: this ties Module 8's keys to the mining and validation we just learned. Next up, the network keeps building on what we covered here.
    • Teacher's Edition9.3 •
    PRINT THIS · YOUR IN-ROOM CARD

    Module 9 cheat sheet

    0:00 intro, nodes vs miners0:08 nodes and minershalvings and supply Proof of Work and difficulty0:55 mempool1:10 transaction flow, wrap-up
    NODES ARE NOT MINERSSay it early, say it often. Nodes validate and store the ledger; miners propose new blocks and compete through Proof of Work. Referees versus players.
    MINING IS NOT "MONEY FROM NOTHING"The new bitcoin is the incentive; the mining work is the security mechanism. Issuance follows a fixed, shrinking schedule (50 to 25 to 12.5 to 6.25 to 3.125 BTC).
    THE PROOF OF WORK LINE"Proof of Work makes dishonesty expensive and verification easy. That is what secures the ledger."
    THE MEMPOOL LINE"A waiting room for valid, unconfirmed transactions. Higher fees usually get picked first, like paying to skip the line."
    "SHOULD I BUY BITCOIN?""We teach how Bitcoin works, not whether to buy it. This is educational only, not financial advice. For personal decisions, talk to a licensed professional."
    RUNNING LONGCut mining economics deep-dives, mining-pool centralization, and 51% attack math first. Never cut node vs miner, Proof of Work, difficulty adjustment, or the transaction flow.
    RUN THE ROOM · GAME CARD

    Transactions in Action (the human network)

    Transactions in Action · 15 TO 20 MIN · MAKES THE TRANSACTION LIFECYCLE PHYSICAL

    SETUP Assign roles with paper cards: one Sender ("Adam"), one Receiver ("Gerardo"), 3 to 4 Nodes, and 3 to 4 Miners. The Sender writes a mock transaction on an index card: recipient, amount, and a fee number. No real money, ever, just paper cards.

    ROUND 1: SIGN AND BROADCAST The Sender "signs" by initialing the card (that is the private key) and hands copies to the Nodes.

    ROUND 2: NODES VALIDATE Nodes check simple rules on the card (is it signed? is the amount filled in?). Valid cards go into the "mempool," a spot on a desk. Invalid ones are rejected out loud.

    ROUND 3: MINERS COMPETE Miners roll one die each; first to roll a 6 "finds a valid hash," takes the highest-fee card from the mempool, and announces the new block. Nodes verify, then it is "added to the blockchain" (taped to the wall).

    DEBRIEF "Who checked the rules? Who added the block? Why did the higher-fee card get picked first? What made rolling a 6 stand in for Proof of Work?"

    POINT Nodes validate, miners compete, fees set priority, and Proof of Work is real effort (the dice) that any node can instantly check. That is the whole lifecycle, played out live.

    REQUIRED REFLEX

    A dad asks quietly after class: "So should I put money into Bitcoin?"

    Same line, every teacher, every time. Never predict prices, never say buy, sell, or hold.
    LAST STEP · YOUR REHEARSAL

    Run one page live, then you are ready

    Pick the page you are most nervous about and run it for the course lead for 5 minutes, printed cheat sheet in hand. A rehearsal, not an audition: you choose the page, you know the bar: ask then wait, speak in your own words, keep nodes and miners clearly separated, and the "should I buy?" line comes out automatically.

    ✔ Ready to teach Module 9
    Based on the Bitcoin Diploma and Educator Guide by My First Bitcoin (myfirstbitcoin.org), used under CC BY-SA 4.0. Changes were made (teacher annotations added). This adaptation is also licensed CC BY-SA 4.0.
    Liberty Villages is an independent 501(c)(3); not affiliated with, endorsed by, or sponsored by My First Bitcoin. Educational only, not financial, legal, or investment advice.