1.PURPOSE:Ethereum main purpose of blockchain is to lets developers build their own applications that use Ethereum’s blockchain for a variety of purpose,while Bitcoin’s blockchain is a public ledger of all bitcoin transactions i.e to keep track all bitcoin transaction.
Bitcoin is created as an alternative to regular money and is thus a medium of payment transaction and store of value, Ethereum is developed as a platform which facilitates peer-to-peer contracts and applications via its own currency vehicle
2.ALGORITHMS USED: for now ethereum is using POW(proof of work) to distribute their coin as of today but will soon move to POS(proof of stake) starting from 28 of may 2017.The algorithm adopted in ethereum is POW but in a special Hash design called ETHASH whereas Bitcoin blockchain also uses a special POW algorithms known as SHA-256.
However,Bitcoin algorithm require miners to solve a complex cryptographic puzzle before they can enter their block of transactions into the blockchain. Bitcoin’s PoW process requires a great deal of computing power, and most bitcoin mining is now done by large companies that invest in specialized equipment powered by Asic chips dedicated to bitcoin mining
ethereum, discourages this type of large-scale mining through, which essentially allows ordinary computers to mine effectively (and less expensively) than Bitcoin does.
3.SCALABILITY:Ethereum’s blockchain is also more scalable than Bitcoin’s. Bitcoin blocks are mined every 10 minutes (on average), while Ethereum’s are mined every 15 seconds, making transactions much faster (about 25 transactions per second, as opposed to Bitcoin’s 3 transactions per second).
4.EFFICIENCY:, Ethereum’s blocks contain a complete record of the block state, which eliminates the need to store the entire blockchain history which make it more efficient than bitcoin blockchain
5.MINING CONCEPT:Ethereum uses a Ghost Protocol that fends off the use of centralized pool mining. Whereas bitcoin still employs the pool mining concept.
The Ghost protocol in Ethereum is (Greedy Heaviest Observed Subtree) was introduced in 2013 as a way of combating the way that fast block time blockchain suffer from a high number of stale blocks – i.e. blocks that were propagated to the network and verified by some nodes as being correct but eventually being cast off as a longer chain achieved dominance, or Forking. The protocol also combats the issue of centralisation bias – the larger the pool the less time the more often they are going to get a head start on other miners by producing the block themselves and immediately start the race for the next block.
Ethereum coin are often refer to ether while Bitcoin is bitcoin (b is not capitalize)