Please, how does real time clock work?

I am working on a project where i need to know the actual time it takes to move from one temperature level to another level. I have heard about RTC,pls will it work? Any help will be appreciated. Thank you all

RTC is a time keeper IC it maintains time by its own hardware circuitry. It has its own crystal. which RTC are you planning to use coz every IC has its own communication interface.