Keeping a Copy Close By
Why the second visit is almost free
About 35 minutesMediumThe Internet and Search
What your child can do at the end
Explain what a cache stores and when it is used
The brief
The fastest request is the one you never make. Browsers keep copies of things they have already downloaded, and when you come back they check whether the copy is still good instead of fetching it again. In this lab you measure a cold page load, then a warm one, and find out exactly how much a cache is worth on a slow connection.
Skills it develops
predictionalgorithmic thinkingdata basics
How it is assessed
3 graded challenges inside the lab, and 8 questions at the end that check the idea rather than the clicks. Every attempt is saved, so a retry after a mistake counts as the learning it is.