If there is no transaction does blockchain size increases? If yes, why?

Question

I have a private blockchain. Even though there is not much transactions going on, the chain's size keep increases. I observe that if there is not any transaction occurs still blockchain size increases, please note that I am not 100% sure.

For example, a block-chain started and there is no transaction occur for a week. In this time does the blockchain's size still get increases? If yes, what might be the reason, since state of the blockchain does not change at all.

Thank you for your valuable time and help.

Answer 1

If yes, what might be the reason, since state of the blockchain does not change at all.

That's not true, each block changes the state because you have a mining reward. Even if all blocks were empty (ignoring mining rewards), there is still the block to be stored somewhere.

Just imagine putting empty bottles into a bag. It get's more and more heavy, even though the bottles are empty :)

Answer 2

Just to add to the other answer...

Empty blocks still add to the security of the chain, so even if there are no transactions happening at the present time, any past transactions will be made more secure by continuing to add empty blocks.

For example, a block-chain started and there is no transaction occur for a week.

In this scenario there are no past transactions, but there's currently no in-built intelligence in the code to determine this. (This is probably where the sealing engine option that 5chdn mentioned comes in.)