This tool is a bit like when you grab a glass of milk from the fridge and one of your kids asks where does milk come from? And you then realise that we often overlook the process behind some of the most common things to discover there is actually an interesting and detailed procedure that needs explaining.
How Google works is the best explanation for students and teachers about how the webs number one tool actually works. It uses animated diagrams and breaks each step down into a very simple information that anyone will understand and really highlights to students the amount of effort and 'nerdiness' that goes into locating your nearest take-away food store in 0.34342 seconds.
So take a look at it here with your students before you use it next time.