Short Student Permie project idea brainstorming

Hi everyone,

I am a teacher, artist and permaculture designer. I have a week long Explore program for kids 5-7th grade at the end of school and I am looking for some more cool projects. I have the kids for three hours each day. I have a variety of projects ready but thought I would ask the super knowledgeable and creative folks here for some ideas. Thanks!

Tim, my reply to another thread (https://permies.com/t/45749/education/Alice-Challenge) may connect with this. However, most of the projects I suggested there don't fit in a week - they're longer research projects intended for a slightly older group. However some, like the solar water heating, might fit your situation.

Also, I'd love to hear more about your list of projects... especially if any are easily expanded into a useful permaculture related research project for the purpose described in the other thread.