PROOF OF WORK (PoW)

Proof of Work was the first consensus mechanism, and its first application was not blockchain or cryptocurrency-related, it was developed to reduce the problem of misuse of computing power to carry out actions like spam emails. This concept was then adopted by Bitcoin in 2009 as the first consensus mechanism in the blockchain industry.
So how does Proof of Work work? Proof of work is a consensus mechanism that verifies that network users, (AKA miners), compute valid alphanumeric codes called hashes to verify transactions and add the next block to the blockchain. It is basically a competition between miners, where the winner of this competition (first to solve the arbitrary mathematic puzzles that form up hashes) is selected to add the newest batch of data or transactions to the blockchain. After this competition, the winner is not rewarded yet until the answer is validated. This validation is done by asking other network users to confirm that the miner who is given credit for computing the valid hash used the necessary amount of processing power.
Now we know how the famous Proof of Work works, now let us look at the blockchains and cryptocurrencies that are built on the Proof of Work consensus mechanism:
BITCOIN (BTC)
ETHEREUM CLASSIC (ETC)
DOGECOIN (DOGE)
MONERO (XMR)
LITECOIN (LTC).
There is one token or coin that is supposed to be here “ETHEREUM”. Ethereum is no longer on the Proof of Work consensus mechanism due to its transition\merge to the Proof of Stake consensus mechanism (We are going to talk about this consensus mechanism next).