I looked up in the sky a few days ago and saw a patchwork of contrails. What causes planes to leave contrails? Why are they more visible on some days? Can you learn something about a plane from the contrail it leaves? (Resource: Fantastic videos about contrails on YouTube!)
How many different types of planes are there? What new planes are currently being designed? Design a better plane. (Authentic Learning – start with a discussion of contrails and see where you end up…)