Computer Science is a subject that studies what computers can do. It's a diverse and overlapping field, but I'm going to split it into three parts. The fundamental theory of computer science, computer engineering, and applications. We'll start with the father of theoretical computer science, Alan Turing, who formalised the concept of a Turing machine, which is a simple description of a general purpose. Tutor people came up with other designs for computing machines, but they're all equivalent to a Turing machine, which makes it the foundation of computer science. The Turing machine contains several parts, an infinitely long tape that split into cells containing symbols. There's also a head that can read and write symbols to the tape, a state register that stores the state of the head. And a list of possible instruction. In today's computers, the tape is like the working memory or RAM. The head is the central processing unit, and the list of instructions is held in the computers memory. Even though a Turing machine is a simple set of rules, it's incredibly powerful and this is essentially what all computers do nowadays. Although our computers obviously have a few more parts like permanent storage and all the other components.