wei

video-scripts/wei.md

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+# Into
+
+When you deploy a contract or create a transactions, in Remix, you will see words like
+`ether` and `wei` in account balance and transaction logs.
+
+What are they?
+
+In this video, I will explain what `Ether` is, and some common units of `Ether` (`ether`, `gwei` and `wei`) .
+
+# Ether
+
+Similary to how US dollar is the currency of US, `Ether` is the currency used within Ethereum, except it's digital.
+
+`Ether` is used to
+
+- reward miners for mining a block
+- pay for transaction fee
+- and you can also transfer it between accounts
+
+The smallest unit of `Ether` is `wei` and one `Ether` is equal to 10^18 `wei`
+
+Here is a complete list of units and the more commonly used ones are
+`wei`, `gwei`, and `ether`
+
+You can use the units `Wei`, `finney`, `szabo` and `ether` inside your Solidity contract.
+
+Let's go through an example.
+
+Here we have our contract.
+
+Inside the contract there is a variable set to one `ether` and another variable set to one `wei`.
+
+Units can be only be added after literal numbers.
+
+For example `1 ether` is a valid code but you won't be able to write `x ether`.
+
+```
+uint pulic x = 1;
+uint public oneWei = x wei;
+```
+
+The only effect of appending a unit to a number is a multiplication by a power of 10.
+
+So 1 `wei` is the same as multiplying 1 by 10 ^ 0, which is simply just 1
+
+and 1 `ether` is equal to multiplying 1 by 10 ^ 18
+
+First compile and deploy the contract.
+
+Call `oneWei` and we can see here that `1 wei` is equal to just 1
+
+Next call `oneEther` and you can see here that it returned a very large number.
+
+This number should be 10 ^ 18, but it's kinda tedious to count the number of zeroes.
+
+So we will let Solidity check it for us.
+
+Over here back in our code, we have a function named `testOneEther`.
+
+Inside this function we check that `1 ether` is equal to `10 ^ 18 wei`.
+We have already seen that a `wei` is equal to 1.
+
+So this function returns `true` if `1 ether` is equal to the number `10 ^ 18`
+and returns `false` otherwise.
+
+Under our deployed contract, hit the `testOneEther` button and the function
+returns `true` just as we expected.
+
+# Gwei
+
+`gwei` stands for `giga wei` and it is equal to 1 billion `wei` (10 ^ 9 wei).
+
+The most common situation where you would see the word `gwei` is when you
+submit a transaction.
+For the transaction fee, you choose the `gas price` in `gwei`.
+
+`Gas` and `Gas price` are the topics of the next video, so for now, all you need to
+know is that `gwei` is equal to 1 billion `wei` and you see it with transactions
+
+For example, visit the block explorer `etherscan.io` and click on any transaction.
+
+Scroll down, click on the transaction details, and you can see here that this
+transaction's gas price was set at 24 `gwei` (// TODO edit value of gas price)
+
+# Conclusion
+
+- `Ether` is the currency of Ethereum
+- 1 `ether` is 10 ^ 18 `wei`
+- 1 `gwei` is 1 billion `wei` and you see it often in transactions
+
+I will see you in the next video