In this investigation, pupils have kept a sleep diary on the days leading up to, and soon after, Sunday 26 March 2017 - when the UK moved its clocks forward for Daylight Saving Time. The aim is to see whether changing the hour has had an effect on their sleep patterns.
The map key shows five discs of different colours and sizes, which represent whether sleep has been lost or gained and six time ranges, from 0 minutes to over 105 minutes.
This key shows what the icons on the map mean
