When data e.g. web pages, emails, instant messages etc are sent across the internet, they are not sent as one big file. Instead, the file is broken up into lots of parts called 'packets'.
The packets are reassembled when they arrive at their destination.
See 'Packet Switching' in the 'What is ....?' section for more detail.
Challenge see if you can find out one extra fact on this topic that we haven't already told you
Click on this link: Packet Switching