Information flow is what the Internet is about. Information sharing is power. If you don't share your ideas, smart people can't do anything about them, and you'll remain anonymous and powerless.

Vint Cerf

Local Networks

A network is just 2 or more computers connected together. Computers can be connected by copper wires, wireless connections (WiFi or Bluetooth), or long glass wires that transmit light (fiber-optic). When you connect individual computers together, you have a local area network (LAN). For example, you have a local network at home. The most common connection for a computer to a LAN is by WiFi. WiFi is the technology that connects a computer to a wireless access point (WAP). You can often see these at school or in stores. They are usually small white boxes mounted to the ceiling. You're very likely connected to one right now! These WAPs connect to a switch, usually hidden away in a closet somewhere, using copper wires. These wires can transmit a lot more traffic than the wireless connection. Computers can also connect directly to a switch, as can printers and other devices. Here is a typical local area network.

Of course, what we usually want to do is connect to other networks, and access devices far away from where we are. When we connect two or more networks together, we create an internet (small "i"). We use a special device for connecting networks together, called a router. Routers look at traffic coming in, and decide where it should go next. The connection between all of the networks that connect together worldwide is called the Internet (big "I"). Your home probably has a device that combines a router, switch, and wireless access point all in one, which allows you to connect to the Internet. 

The Internet