# Transaction in a block vs a new block

I am writing a study work related to blockchain and the potential in my area of working. Therefore I am now analysing how blockchain works.I have some confusion and hope somebody here can help me with a good source or directly help me to understand it.

I use the bitcoin blockchain as example to explain it.

Person A send Person B xx amount of btc
the transaction is not yet on the blockchain (unconfirmed)
The nodes (miner) verify the transaction mathematically in a block and chain in in the blockchain
TX is confirmed and Person B receives xx amount of btc -> this I got!

Now every 10min a new block is generated with xx amount of BTC (Based on the algorithmus)

The Blockchain runs with SHA-256, every block has a unique hash so every miner understands where is the current ending of the blockchain.

My problem is to understand/connect those three points, I wanna illustrate it on a timeline.

We have a chain lets say this chain has only 5 blocks. So the miners look for the 6th block. The 5th block has a unique hash so every miner knows where to line up the 6th block.

Then we have a list of unconfirmed transaction, every TX has a little incentive fee for the miners.

The miners work (verify old Tx and search for a new block)
I read that they have to solve mathematical quizzes -> where is the link to a new block then?
Do they create blocks while searching for a new block with btc inside?
-> if a new block is found has this block also Tx inside? Does somebody has a sample on the blockchain?
Do they then use those blocks, add Tx and match it to the blockchain?
How many Tx can go in a block?
Are there also empty blocks?

Sorry if my questions sounds stupid.

You questions are legit, however they might need a bit of reorg.

where is the link to a new block then?

Do they create blocks while searching for a new block with btc inside?

a miner "creates" a block by selecting tx from the pool and "solving the math problem" as you said. Other miners are doing the same thing. When someone else solves a block before you do, she broadcasts it and you'll receive the block through the p2p network. If that's a legit block, it usually makes sense to stop your work on the current block and work on the next one on top of the one you just received.

if a new block is found also has this block'a Tx inside?

it's totally possible, depending on what tx you select and what tx the other miner selects

Does somebody has a sample on the blockchain?

If you mine, then every scenario would be like this

Do they then use those blocks, add Tx and match it to the blockchain?

if "those" means the new blocks you receive while mining, then no, you just accept it after validating it, and then solve for new blocks on top of that.

How many Tx can go in a block?

as little as one (that pays to the miner), and as many as the number of tx that fills the block (such that the total size of tx data is less than 1 MiB)

Are there also empty blocks?

yes if empty in the sense that no other tx except for the one that pays the miner. It happens more often in the early stage, but it still happens nowadays.

• Sorry for my late respons and many thanks for your detailed answer, I do understand I much better now! This means in general it takes 10minutes for a Tx to get processed? (if we pay the required fee and this point of time) I ask myself what the miners do in the other 9min? Do you know any resource which has more information about "solving the math problem" to explain better what the miners are doing to find a block?
– dan
Commented Apr 29, 2018 at 10:01
• I just read that the network can adjust the complexity of those tasks for the miners, to secure the 10min blocktime.
– dan
Commented Apr 29, 2018 at 12:45