The first time I ran this activity, it took me over 8 hours to plan - from choosing appropriate resources for the girls to investigate, to creating the QR codes, finding places to put them along with clues to help the girls find them... and of course, a short trailer to introduce the activity. Thankfully, it doesn't quite take as long to organise as this anymore - but checking all the QR codes, re-distributing them, finding iPads that work, etc was still all necessary.
Thankfully the weather yesterday was beautiful. I was able to get to school early and put all the QR codes out before the students arrived.