I taught a lesson last Wednesday on pedigrees. (A pedigree is similar to a family tree but shows what and how physical traits are being passed from generation to generation.) I typed up my lesson plan and made worksheets for this pedigree lesson. I thought I had everything figured out. Well, for the most part, the lesson went smoothly. I went over what a pedigree was, what shaded and unshaded circles or boxes represented, and how the lines between these shapes either meant that these people were the parents or the offspring. I showed them the difference between a phenotype and a genotype, just in case they forgot. The students responded well to the review and even helped me use the whiteboard.
Next the students numbered off into groups of about 3 students and worked on the "Who done it?" worksheet. The assignment was titled, "Who stole the Big East Championship trophy?" I typed up a short story about a family named the "Pittsburghlars" who have always sent their children to Pitt and have always been jealous of WVU sports. One of the Pittsburghlars stole the trophy and my students had to use the clues about the burglar from the story and the pedigrees to figure out who stole the trophy.
There was just one problem with this lesson. Time. Some students got the burglar right away, while some students struggled with the pedigrees. I am now concerned about how to manage my time in the classroom when some students get done so quickly wile others may take all period.
How do I write lessons that accommodate for student differences in the length of time it takes them to complete assignments?