An Arduino is a small programmable computer that we can use to make all kinds of clever interactive gadgets and gizmos. It is not a computer like the laptops we have on our desks, because rather than having only one set of inputs and outputs (the keyboard and mouse, and the monitor), it has literally dozens!.
Your Arduino uses any one of its 15 sockets (we usually call them ‘pins’, because of the shape of the wires we use to connect to them), to interface with a huge number of sensors and switches for input, or outputs like lights and motors - basically any other piece of technology that uses electricity. Here’s a close up picture of an arduino with a few handy labels showing you what all the different bits do:
Although it’s inputs and outputs are different from other computers, just like them we can program it. In fact with an Arduino, this is absolutely essential! Without instructions telling it how to deal with inputs, what calculations to make with data, and what to do with its outputs, it’s really nothing more than a pretty blue piece of metal and plastic.