The 5-Second Challenge

This activity challenges students to get as close as possible to 5 seconds - and later 20 seconds - using a stopwatch. After asking them to do so with eyes open and eyes closed, some fun discussions on variability and standard deviation ensue. This lesson assumes students have talked about the idea of variability and what it "looks like", but does not assume they know what standard deviation is or how to calculate it. There is an option to end with a demo on calculating standard deviation using a table component in Desmos before students try it themselves by hand or with technology. Here is a quick "teacher tip" document for how to do this: https://drive.google.com/file/d/1rO4IO7aKi5cpeKnf7JoL0zCuwBK4fuam/view?usp=sharing Thanks to Allan Rossman (@allanjrossman) for a nice practice context using fictional restaurant ratings (last two screens) and to Jay Chow (@mrchowmath) for some behind the scenes assistance in creating the activity. Find me on Twitter: @kevinji Last updated: September 2026

By Kevin Ji