As this course is designed to be focused on how to buy Crypto and store it safely as a beginner and is a jump start course, I won't go too deep about the technology but if you'd like to read deeper you can Google anything in this course. A resource I could recommend to learn deeper about Blockchain is here. But there is many more resources you can find.
What is a blockchain?
In a nutshell, there are many blockchains as of today. To put it simply, a blockchain is a network database that records every transaction the users of the blockchain network have completed. Anonymous "wallets" (a string of codes) that are owned by users of the blockchain (you) use your digital wallet to buy or sell, buy NFTS, send funds, receive funds and with smart contracts, a huge number of use cases are emerging and being innovated. I will show you later how this process works, don't worry if it doesn't make sense yet.
Some compare Blockchain to an excel spreadsheet, because it is like a database that is saving information. The reason it is "decentralized" is because the server isn't owned by one entity. If it was, then they could control what happens and change the data record freely. With Blockchain, specifically Bitcoin, it is called a Proof - of - work chain. In proof of work, "miners" are people with huge powerful energy consuming computer rigs that are solving calculations or sort of digital puzzles that when solved, rewards the miner(s) with Bitcoin! Because there is over 10,000 of these computers around the world doing this same job, they spread the database record on all these servers and update simultaneously in real time together.
Say you put a transaction on the blockchain to send 0.2 BTC to Suzie; the database (blockchain) would receive a request for the transaction, you'd pay a network fee in Bitcoin called (GAS) and miners all around the world check their records to see if you really do have 0.2 BTC in your wallet to send Suzie, and when the records show you do, the transaction gets approved and the transaction completes. Miners all around the world are all asking each other if the network record is correct and showing the same information throughout all of the computers.
If a hacker want's to change his digital wallet computer code to say he has 10,000 Bitcoin, then the other 99.9% of computer miners would say "NOPE! That doesn't show in our record" . And the hackers transaction get's cancelled out.
As long as no individual owns more than 50% of the mining servers, Bitcoins database cannot be changed.
For you, your excel spreadsheet is saved in a centralized way (inside your own computer). With blockchain, the spreadsheet is saved in tens of thousands of computers around the world. Every time a transaction goes through, as long as 50% of the network nodes (or computers) agree the transaction is legitimate, then it completes and saves in the database (Blockchain) permanently and can never be changed. This Blockchain database can be viewed publicly and shows every wallet address and how they interacted with other.
So for example:
Let's say your name is Bob and you're sending 0.001 Bitcoin to Suzie.
So if we reviewed your transaction on the Blockchain, it would show something like this:
Contract code: 2F4rj23Sdjf4skn92Fjd29jf3jf249fs4s 0.001 BTC > hkF49fgxn4ls2gns5sF9dk2F9521jd04
Which basically means,
Bob's wallet address "2F4rj23Sdjf4skn92Fjd29jf3jf249fs4s" sent
0.001 BTC To Suzie's wallet address: hkF49fgxn4ls2gns5sF9dk2F9521jd04
As long as Bob has Suzie's wallet address, he can send Bitcoin to her at anytime without anybody's permission. By looking at the database records, you can see anonymous wallet addresses sending funds to each other, but it does not attach identities to the wallet address, so the people transaction are anonymous. (Of course some people get found out)
For example: We know the Bitcoin creators (Satoshi Nakamoto)'s wallet address and can look at his coins which haven't been touched for many years. Also, we have Vitalik Buterin, the creator of Ethereum Blockchain Network wallet address.
Using a website like Blockchain.com/Explorer you can copy/ paste the bolded text (wallet address) below to see Satoshi's wallet.
Satoshi "Genesis" address : 1A1zP1eP5QGefi2DMPTfTL5SLmv7DivfNa
Vitalik Buterin (the creator of Ethereum)
Wallet address (Ethereum network) 0xab5801a7d398351b8be11c439e05c5b3259aec9b
This means Blockchain is very transparent, and you can see everyone's activity on the blockchain, making it more transparent than fiat paper currency. While viewable to other people, the funds are untouchable, and can only be accessed by you.
What is the between a Coin and a Token?
A Coin means it is the native currency of a block chain.
So for example:
Bitcoin (BTC) is a coin because on the Bitcoin blockchain, to pay for gas (transaction fees) you use Bitcoin.
Ethereum (ETH) is a coin because on the Ethereum blockchain, to pay for gas aka GWEI (transaction fees) you use Ethereum.
Other networks (Blockchains) that also are coins :
ADA (Cardano)
SOL (Solana)
BSC (Binance Smart Chain)
MATIC (Polygon)
AVAX (Avalanche)
and many more. They are coins because their network uses their coin as the native currency and for paying for transactions.
Token
You will hear about tokens a lot in the crypto space, some will mistake it as a coin but its not exactly accurate. On a more sophisticated block chain such as Ethereum, they added another layer of functionality called "smart contracts". These smart contracts are basically programmed codes that have additional functions above just sending coins around the network such as tokens (digital currencies built on Blockchain), NFT (digital art) and more.
Tokens are the same as coins, except they are not the coin that is used to pay gas on the blockchain network. What I mean is Bitcoin is a coin, it has it's own Bitcoin Blockchain and when you use it, you use Bitcoin to pay fees. That's what makes it a "Coin".
On a blockchain like Ethereum, it's the same as Bitcoin where you pay for gas fees using Ethereum. That's why Ethereum is a coin too.
But because Ethereum is more advanced than Bitcoin and has something called "smart contracts", you can build a new type of currency called "Tokens".
So let's say I want to make a token for my computer company, "Pears .LTD" and decide I want my very own currency for my customers! Well I decide to make the Pears token, but I don't want to make an entire blockchain to support this token and have it be a coin; as this would be a lot of work and be costly. So I think, "okay, I like the Ethereum network, and think I will launch my token on their network." With smart contracts this is possible. Now to buy my Pears token, you just need some Ethereum (ETH) to pay for the transaction fee and then you have your very own Pear token stored safely in your wallet in the Ethereum blockchain. If this is confusing, that is okay, as you progress through the course and start applying these concepts it will make a lot more sense. Feel free to continue.
So for example:
Bitcoin (BTC) is a coin because on the Bitcoin blockchain, to pay for gas (transaction fees) you use Bitcoin.
Ethereum (ETH) is a coin because on the Ethereum blockchain, to pay for gas aka GWEI (transaction fees) you use Ethereum.
Other networks (Blockchains) that also are coins :
ADA (Cardano)
SOL (Solana)
BSC (Binance Smart Chain)
MATIC (Polygon)
AVAX (Avalanche)
and many more. They are coins because their network uses their coin as the native currency and for paying for transactions.
Token
You will hear about tokens a lot in the crypto space, some will mistake it as a coin but its not exactly accurate. On a more sophisticated block chain such as Ethereum, they added another layer of functionality called "smart contracts". These smart contracts are basically programmed codes that have additional functions above just sending coins around the network such as tokens (digital currencies built on Blockchain), NFT (digital art) and more.
Tokens are the same as coins, except they are not the coin that is used to pay gas on the blockchain network. What I mean is Bitcoin is a coin, it has it's own Bitcoin Blockchain and when you use it, you use Bitcoin to pay fees. That's what makes it a "Coin".
On a blockchain like Ethereum, it's the same as Bitcoin where you pay for gas fees using Ethereum. That's why Ethereum is a coin too.
But because Ethereum is more advanced than Bitcoin and has something called "smart contracts", you can build a new type of currency called "Tokens".
So let's say I want to make a token for my computer company, "Pears .LTD" and decide I want my very own currency for my customers! Well I decide to make the Pears token, but I don't want to make an entire blockchain to support this token and have it be a coin; as this would be a lot of work and be costly. So I think, "okay, I like the Ethereum network, and think I will launch my token on their network." With smart contracts this is possible. Now to buy my Pears token, you just need some Ethereum (ETH) to pay for the transaction fee and then you have your very own Pear token stored safely in your wallet in the Ethereum blockchain. If this is confusing, that is okay, as you progress through the course and start applying these concepts it will make a lot more sense. Feel free to continue.