What you just did (adding a new block by finding its nonce value) is called “mining”. It requires computers to do some work of solving the puzzle and show the proof of this work (the valid nonce) to add a new block. 

This process (“proof-of-work”) is how our different computers build consensus on which blocks are valid. 

💡 Tip: The number of zeros required by the puzzle determines its difficulty. More zeros mean a more difficult puzzle that takes more time. 

As your computer is scanning nonce values one by one, you’re coming up with many different hash values. A stronger computer can make guesses and test these faster than a slower computer can. The number of hash values you come up with every second is called the "hash rate". 

Of course, a computer spends energy when trying to solve the puzzle. Forcing computers to spend energy is an inherent design feature of how our blockchain (and Bitcoin blockchain) builds consensus between different computers.

Hash rate. Mining. Nonce. You've heard of all these terms before but now they make sense, right?