Well, that would vary enormously.
However, lets start with what it will NOT consist of, probably, if it really IS computing science:
Opening PCs and playing with them,
Talking about the technology behind hard drives and graphics cards,
Messing around with screwdrivers in ANY way,
Installing operating systems
Installing software and games
Studying new hardware and what it does
You may get one or two modules in networking, but that will be all
Basically.... drum roll....
NOTHING WHATSOEVER TO DO WITH ANYTHING THAT HAPPENS IN THIS SITE AT ALL....!
Please be sure about this.
"Computing" means a HELL of a lot of things.
What you might think of as computing is something that someone else might not. You might be a complete expert in some things, and be rubbish at or even HATE some other things WITH A PASSION!
You have to be very careful now about what you choose, because you will have to do it for several years, and not give up, unless you are convinced that you have made the wrong choice.
And so you must think very hard right now about making the correct choice.
Here is what you will probably be doing in your first year computing science degree:
Programming concepts
Program design concepts, organised into charts and diagrams showing relationships between datatypes like classes and other such things,
Project management
Things about machine code, assembly language, basic, etc
Starting to code in languages like C, C++ and Java.
Internet technology courses, dealing in internet theory
Programming in HTML to design a web page of your own
Using Microsoft Office, and showing that you understand word documents, spread sheets, etc.