Engineering may not be something that you had considered teaching, but with the help of a great curriculum that is easy to use, you may want to reconsider. Plus, the curriculum is free! The Museum of Science, Boston, has made available two levels of engineering curriculum, elementary and middle school, with many curriculum units for each level. The topics are kid-friendly and fun to explore. The curriculum was created to be used as an enriching out-of-school time experience for students and I have found that it works wonderfully for homeschooling, especially for groups.
The Engineering Adventures® curriculum units are designed for grades 3–5, but I was able to successfully use the material with grades 1–3 with only minor adaptions. The Engineering Everywhere® curriculum units are designed for middle school, but I was able to use the material with grades 4–7. Some of the units require lots of supplies, usually household items, so you do need to have materials prepared. There is an option to purchase a kit of supplies, but I found that I either already had or was able to easily acquire what was needed. The units also have optional student journals that you can print to go along with the curriculum. I chose not to do this because of cost and allowed the students time to discuss their findings instead of writing them. Overall, I had a very positive experience using this curriculum and would strongly recommend it.