Explain Like I'm Five

So operating systems are huge, they do a lot of things. They require a lot of memory and storage and some of their tasks like connecting to devices and generating images take up resources. They run a lot of programs at any given time to do all these tasks.

The kernel is a computer program but think of it as the MAIN program. It’s at the core of a computer's operating system. It’s the first program the hardware loads when you turn the computer on and it has complete control over everything in the system. It is the portion of the operating system code that is always running, always in RAM, and closing it crashes the entire computer or shuts it down. The kernel connects the hardware to the software. A full kernel controls all hardware resources (RAM, data from keyboard and mouse, data to graphics card and therefore screen), and manages all the programs running. It gives each program access to memory and the processor and even the internet. The kernel prioritizes programs and those requests.