We started a week ago with a quantitative look into converging lenses. Our pre-lab began by finding the rough focal length of some lenses, and some basic data gathering to find the relationship between object and image distances. Then in the full lab we derived the lens makers equation, magnification equation, sign conventions, and lens power.
For the post-lab, instead of simply writing up a conclusion, I have assigned a post-lab, lab practicum: find the focal length and lens power for an unknown converging lens. Also, calculate and set up the lens system, so that image size is 3x the object. No trial and error.
This post-lab does not just tell me what they learned, it also shows me what students learned and what they can do with the knowledge they gained.