We just finished up our school year and spent the last 3 weeks of school exploring engineering. Honestly, it was my favorite part of the year! We'd just finished up our standardized testing and had a little 'breathing room' but needed to keep the kids engaged. I introduced the topic by having a few different engineers come in to have quick chats with my kids, and we watched the movie 'Meet the Robinsons' to talk about engineering, inventing, and the scientific process. We then began a theme unit centered around a book that I found called Survival by Gordon Korman. While reading a few chapters aloud each day (the story is about a group of 6th graders stranded on a desert island) we had mini engineering challenges where the students were asked to build a hut, build a rope bridge, build a waterproof container, build a catapult (their favorite by far), and then finally build a raft or boat. I found a great resource on teacherspayteachers.com that gave rubrics and guided the students through the engineering process. It really helped us to focus on the brainstorming, designing, building, testing, and then reflecting process. The students loved it. The last few days of school they were begging to skip recess so that they could work on their boats & rafts. It's a great little unit that can be easily differentiated to be harder or easier. I challenged my students to create a rope bridge using only yarn and popsicle sticks that would support the weight of a 12 oz. soda.
The students became very competitive and really enjoyed the challenges. I kept a spreadsheet of points by individual student, that way I could shuffle and rearrange their groups for each different challenge. At the end of the unit, I awarded a prize to my top engineers in each class.
Hope this helps,