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WHAT IS THE DIFFERENCE BETWEEN POW AND POS? ADVANTAGES AND DISADVANTAGES? WHICH ONE IS BETTER FOR SCALING CAPACITY.

To clearly state the difference between POW and POS, we will first have to understand the meaning of both POW and POS.

Brief Definition of PoW and PoS.

Proof of Work (PoS)

Proof of Work denoted as PoW is known to be an original consensus algorithm that requires an agreement between blocks in a network to confirm a transaction. Adopted by Bitcoin in 2009, Proof of work was created as a proposed solution to solve the numerous problems of spam email. Proof of work also provide Crypto miners with secure and safe way to mine coins without a third party.

Proof of work requires enormous power in solving mathematical/cryptographic problems in an effort to deter the abuse of computing power in sending spam email/ malicious transactions. Immediately these Cryptographic problems have been solve, the transaction is then confirmed and initiated.

Proof of Stake.

Proof of stake is another consensus on a blockchain network that stemmed from proof of work but unlike the proof of work consensus, the proof of stake doesn't involve solving huge and complicated cryptographic problems. Here, owner stake their tokens that are being used for mining. These token are considered to be collateral for user to mine coins. And so those who stake their tokens received rewards of new coin according to the amount of token they staked.
The proof of stake concept was developed in 2012 by Scott Nadal and Sunny king as an alternative for proof of work Concept.

DIFFERENCE BETWEEN PROOF OF WORK AND PROOF OF STAKE.

Proof of Work	Proof of Stake.
Adopted by Bitcoin in 2009 and still in used up to date	Mostly used by altcoins.
Mining of new coins take a minimum of 10 minutes. That's why Bitcoin mining takes longer	Mining of new coin takes shorter, maximum of 2 minutes.
Involve solving complex cryptographic problems to mine new tokens	Involves staking tokens/coins to mine new coins.
Can perform a limited amount of transaction simultaneously, a maximum of 5	Can perform numerous transaction at the same time, up to 15.
Requires huge electric power to mine	Doesn't require huge electric power.
Costly to operates because of time, electricity and sophisticated computer gadgets	Less costly to use since multiple transaction can be done at same time and doesn't require much electricity.

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Advantages and Disadvantages.

Proof of Work.

Advantages	Disadvantage
It is a very valuable consensus since it host the largest and first cryptocurrency. Since it is not easy to solve a Cryptographic problem, very few miners engage in it and any miner who does is rewarded with Bitcoin which is very high and profitable now	The time to confirm a transaction and mine a coin is very long, minimum of 10 minutes.
It's is competitive and requires agreement between miners	Expensive to run. The PoW requires very sophisticated computer gadget which are expensive to acquire.
Reward miners with blocks and a share of transaction fee	Might result in long disincentives to miners as competition is stiff and mining a new block is unsure.
It is more secure	.

Proof of Stake.

Advantages	Disadvantages
Fast transaction confirmation and rewards to miners	Less secure and more susceptible to low cost attacks.
Doesn't require huge electricity consumption or expensive computing gadget to mine, so it's less expensive	Top stakers can make decisions and affect change, there by leading to a centralized system.
Takes shorter time to confirm transactions.

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WHICH ONE IS BETTER FOR SCALING CAPACITY.

Proof of stake is better for more scaling capacity. As can be seen from the explanations, the length of time that is required to mine in the Proof of Work concept is 10 minutes minimum since it involves solving complex cryptographic problems. This also requires sophisticated computer gadget that and huge electricity consumption that are expensive. More to that, the limited transaction of PoW has made it not to be very efficient and less scalable.

It is for this reason that Scott and Sunny brought up Proof of stake as an alternative to the proof of work.
The PoS is more efficient and more scalable for the following reasons

• Transaction time. The time to confirm a transaction on PoS is maximum 2 minutes.
• Multiple transaction at the same time. Up to 15 transactions can be confirm at the same time in PoS.
• Low cost. Staking of token doesn't require huge electricity consumption or computer gadgets.

These has made Proof of Stake to have more scaling capacity than Proof of Work.

Thank you professor @sapwood for the lessons and assignment. It was beautiful and I enjoyed doing this assignment.

CC. Professor @sapwood.