Science Co-op - floating structures

The boys enjoyed science co-op again this week, although I had to miss it because of work (sigh). Hubby Jim took them, and our friends Henri and his dad Tristan graciously took some pics for us. The boys worked together to build a structure that could not only float, but support a 2lb weight as well. They always love the building part of these days, but the 'testing' to see if their creations can do what they intended is always a time of great tension, excitement, and pride. I think that we have some engineers in the making...