Lesson 6 of 8
The big picture
Show on a big screenThe five ideas, in order:
| Idea | Remember |
|---|---|
| Networks | A message travels along a path of working links. If one path is cut, it uses another, if there is one. |
| A web address | The part before the slash names the computer. The part after it names the page. |
| Asking and answering | Your phone sends a request. A server sends an answer. Each piece of a page needs its own. |
| Search | A search reads an index built earlier. It lists only pages the engine has visited. |
| Cables and radio | Radio carries the short first hop from a phone. Cables carry most of the rest. |
You tap. A request leaves by radio, then travels on by cable. The request goes from one computer to the next. A server sends the page back, in pieces.
If you searched first, your words were matched against a list. The engine wrote that list before you asked.
Where is a page before you ask for it? On another computer, waiting for a request.