Computer science is a review of computers and assessing its concepts. It comprises both hardware and software aspects. Hardware is the basic design of computers and how it works. All those parts which are tangible i.e, you can touch - is the hardware of a system.
It is a fundamental understanding of how a computer performs its calculations and the other advanced concepts.
Hope I'm not answering a homework question but I'd say that hardware is any part or peripheral of a computer that you can touch. While you can touch the media software comes you can not touch the electronic codes themselves.