This is why Computational Thinking has been called the '21st Century Skill Set', and is important for everyone to learn. It is critical to understanding how the digital world works, for harnessing the power of computers to solve tough problems, and making great things happen! It also enables us to think critically about not just the benefits of certain technologies, but also the potential harm, ethical implications, or unintended consequences of these.
But what exactly is Computational Thinking? Let's have a look at a technical definition...
Phew, it's quite a mouthful isn't it? But, as we like to say at CS Unplugged, it's just big words for simple ideas! 'Information-processing agent' means anything that follows a set of instructions to complete a task (we call this 'computing'). Most of the time this 'agent' means a computer or other type of digital device - but it could also be a human! We'll refer to it as a computer to make things a bit simpler. To represent solutions in a way that a computer can carry them out, we have to represent them as a step by step process - an algorithm. To create these algorithmic solutions we apply some special problem solving skills to. These skill are what make up Computational Thinking! And they are skills that are transferrable to any field.
Computational Thinking could be described as 'thinking like a Computer Scientist', but it is now an important skill for everyone to learn, whether they want to be a Computer Scientist or not! It's interesting, and important, to note that Computational Thinking, and Computer Science, aren't entirely about computers, they are more about people. You might think that we write programs for computers, but really we write programs for people - to help them communicate, find information, and solve problems.
Algorithms are at the heart of Computational Thinking and Computer Science, because in Computer Science the solutions to problems are not simply an answer (e.g. '42', or a fact), they are algorithms. An algorithm is a step-by-step process that solves a problem or completes a task. If you follow the algorithm's steps correctly, you will arrive at a correct solution, even for different inputs. For example, we can use an algorithm to find the shortest route between two locations on a map; the same algorithm can be used for any pair of starting and finishing points, so the solution depends on the input to the algorithm. If we know the algorithm for solving a problem then we can solve that problem easily, whenever we want, without having to think! We can just follow the steps. Computers can't think for themselves, so they need to be given algorithms to do things.
Abstraction is all about simplifying things to help us manage complexity. It requires identifying what the most important aspects of a problem are and hiding the other specific details that we don't need to focus on. The important aspects can be used to create a model, or simplified representation, of the original thing we were dealing with. We can then work with this model to solve the problem, rather than having to deal with all the nitty gritty details at once. Computer Scientists often work with multiple levels of abstraction.
The picture you took is stored on the computer as a big list of pixels, which are each a different colour, and each colour is represented by a set of numbers, and each of these numbers are stored as binary digits! That's a lot of information. Imagine if when you adjusted the colours you had to go through and look at all the colour values of every pixel and change each and every one of those! That's what the computer is doing for you, but since you don't need to know this to accomplish your goal the computer hides this information away.
Spotting patterns is an important part of this process, when we think about problems we might recognise similarities between them and that they can be solved in similar ways. This is called pattern matching, and it's something we do naturally all the time in our daily life.
There are different ways we can evaluate our algorithmic solutions. We can test their speed by implementing them on a computer; or we can analyse them by counting or calculating how many steps they are likely to take. We can test that our algorithmic solutions work correctly by giving them lots of different inputs, and checking they work as expected. When we do this we need to think about the different inputs we test, because we don't want to check every possible input (often there's an infinite number of possible inputs!), but we still need to know if our algorithmic solutions will work for all inputs. Testing is something Computer Scientists and programmers do all the time. But because we can't usually test every possible input, we also try to evaluate a system using logical reasoning.