I greets you all in the community. I extend my innermost appreciation to professor @sapwood for this lecture.

WHAT IS THE DIFFERENCE BETWEEN PoW & PoS? ADVANTAGES & DISADVANTAGES? WHICH ONE IS BETTER IN SCALING CAPACITY? EXAMPLES?

INTRODUCTION

In any given blockchain, blocks are related in a Chronological way so as not to allow existing transaction be charged or cancelled. The chains expansion is undirectional which means that adding new blocks is the only way to update a blockchain. In public networks, any node can be eligible to participate in the creation of new blocks, and if then becomes the job of the consensus algorithm to decide which nodes becomes"miners" or validators.

The consensus mechanism is important because it protects the system against malicious nodes that can intentionally break the predefined rules and also may try to conduct fake transactions or organize distributed denial of service attacks.

Proof of Work(PoW)
The concept of Proof-of-work was first proposed in the year, 1993. To fight against any fraudulent activities and abuse of computer services like spamming. The concept was later popularized be Satoshi Nakamoto in year 2008 to validate new blocks in the Bitcoin network.

Proof of work is a decentralized consensus mechanism that avoid tokens being spent in multiple ways or consensus mechanism that give details how decentralized networks are in line with transactions so as to avoid spending multiple tokens.

Proof of work is widely used in cryptocurrency mining for validating transactions and mining new tokens. In other words, its application is determined mostly in mining. As soon as miners successfully created a valid block, he gets rewarded. The most famous application of Proof of Work(PoW) is Bitcoin. Bitcoin is the first crypto currency to adopt use of proof of work as a method of verifying it's transactions in the Blockchain.

(PoW) in blockchain is used in solving mathematical puzzle which can easily provide the solution. Proof of work can be implemented in a blockchain by the Hashcash. Proof of work system is more like a computational puzzles for miners to solve. These puzzles are difficult to solve but much more simpler to verify. If a miner actually solved this puzzle, other miners will therefore verify the solution to see if it's correct and if then correct, they get to place a block on the blockchain. It is therefore impossible to add a new block to the Blockchain without first validating the result of the puzzle.

Examples of Cryptos that uses proof of work(PoW)

• Bitcoin
• Ethereum
• Bitcoin cash
• Litecoin
• Monero.

Proof of stake(PoS)
Proof of stake is the second most popular or consensus mechanism after proof of work (PoW) in terms of the market capitalization of the blockchain networks deploying it.

Proof of stake algorithm was Introduced first in 2011 on Bitcointalk. Peercoin adopted it first in combination with proof of work, albeit the consensus algorithm has rapidly become more dominant in all it's variations. Proof of stake came out as an alternative to PoW which is the oldest consensus mechanism and it was first introduced with Bitcoin. Despite the success early achieved by Bitcoin, PoW couldn't meet the higher demand for throughput, as later blockchains required greater scalability and faster transactions rates.

The process for validation in proof of stake is called "forging". If a node wants to participate in the block creation process, it has to stake the native token. There totally do not need to speed on electricity or purchase specialized hardware for mining.

How does PoS work?

The Proof of Stake algorithm uses a pseudo-random election process to select a node to be the validator of the next block, based on a combination of factors that could include the staking age, randomization, and the node’s wealth.
It’s good to note that in Proof of Stake systems, blocks are said to be ‘forged’ rather than mined. Cryptocurrencies using Proof of Stake often start by selling pre-mined coins.

In a situation where Proof of Work-based systems more and more cryptocurrency is created as rewards for miners, the Proof of
Stake system usually uses transaction fees as a reward.

Examples of Cryptos that uses proof of stake(PoS)

• Cardano
• Tezos
• Algorand

DIFFERENCE BETWEEN PoW and PoS

S/N	PROOF OF WORK	PROOF OF STAKE
1	Blocks are mined in Proof of work	In proof of stake system, blocks are forged.
2	Proof of work: The probability of mining a block determined the amount of computational work done by a miner.	Proof of stake: The probability of validating a new block is determined by how large of a stake a person holds ie, how many coins they posses.
3	Proof of work is more decentralized.	Proof of stake is less decentralized. Reason, the selection is basically on numbers stakes an node holds.
4	Proof of work has low transaction speed and scalability.	Proof of stake has higher transaction speed and scalability.
5	In proof of work, miners received reward for creating a block.	In proof of stake, validator don't receive a block reward instead they collect just network fees as the reward. The network fee could simply refer to any transaction charged when processing a cryptocurrency transfer. The network fee is typically paid for by the encoder and decoder through cryptocurrency miners.

ADVANTAGES OF PoW:

• Proof of work models reward miners with both a block reward and a share of transaction fees.

• Proof of work prevent multiple spending of tokens.

• Proof of work make a blockchain more difficult and costly to attach.

• Proof of work is more decentralized because it's peer-to-peer and you also have control over your mining ability.

DISADVANTAGES OF PoW:

• Proof of work system consums massive amounts of energy to power the computer for miners.

• Proof of work models require access to significant (and increasing) computational power, much of which is wasted each time an equation is solved.

• Proof of work models result in long-term disincentives to mining as newly minted cryptocurrencies near the cap.

ADVANTAGES OF PoS:

• Proof of stake models do not require the computational power associated with proof of work and are therefore more energy efficient.

• Proof of stake models offer better rewards for nodes which stake their cryptocurrency.

• Proof of stake has higher transaction speed and scalability.

DISADVANTAGES OF PoS:

• Proof of stake is less decentralized because the selection is basically on numbers stakes an node holds.

• Proof of stake models are often less secure and more susceptible to low-cost attacks.

WHICH IS THE MOST PREFERRED ONE IN SCALING CAPACITY
Let's first look at what scalability mean!.

Scalability is a term commonly used in the Blockchain world. It refers to the ability of a computing process to be used or produced in a range of capabilities. In a more “Blockchain” context, it refers to the ability of the network to sustain a higher number of occurrences.

Scalability has effective tools and is high in cases of observing and recording a transaction in blockchain. For that reason, in other to increased transaction speed, transaction throughput and top security, the scaling capacity has to be high.

However, proof of stake (PoS) is certainly more advanced than Bitcoin proof of work (PoW) approach in terms of scalability and speed of transactions because it has no computational power need to solve difficult puzzles.

Without scalability you can only be able to transact with a small network, you can not participate in a global financial system. No user would have to compromining any of this very important properties.

EXAMPLES OF CRYPTOS WITH HIGH SCALING CAPACITY ARE AS FOLLOWS

SOLANA (SOL) on a scaling capacity, this crypto runs about 50,000 transactions per second. with an approval time of 5 minutes.

RIPPLE (XRP)
Cryptos runs about 1,500 transactions per second. with an approval time of 3.5 seconds.

NEO: In NEO, cryptos runs about 1,000 transactions per second. In 15 second.

COSMOS (ATOM) Here, Cryptos run about 10,000 transactions per second. with an average time of 2.3 etc.

CONCLUSION
Consensus Mechanism linked an agreement on a blockchain in other to enable any work done in the block have fast verification of transactions.

The reality could be that there isn't just one correct solution for scaling. Each project may need to look at how it is being used and ask what path or paths are best for it.
However, new strategies and technologies are emerging that could shake up the whole game at any time.
A combination of many ideas and more will ultimately shape how cryptocurrency reaches a mass audience, but the problem needs to be solved before it does. Otherwise, it is possible that a centralized, permissioned chain will be the only kind that will be accessible to a global population.