Direct Instruction
Have the crime scene set up before students come in, and also have all the fruit and equipment ready to go in small groups. Students should gasp at the drama and be excited for the lesson! Then you can go through the slides of the suspects and why each step is necessary for the extraction, before handing out the instruction sheet. Move around the room supervising and chatting to students about what they're doing. Go through a presentation about DNA while their practical incubates. At the end, pretend to leave the room and run their results through “gel electrophoresis” (if they have questions about this - mine didn’t - then it could be a good teachable moment!) Let them form a conclusion based on the gel electrophoresis about who the murderer was. Then you can dramatically reveal the motive!
