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!
If I did this lesson again I would have CSI music playing in the background as students came in, and amp them up a bit more as I revealed the suspects in a dramatic way. Having the crime scene set up as students entered the room was great fun, and they were scandalised with the murder of Perry the Pear. Most enjoyed the characterisation of the suspects. Students were so excited to crack on with this lesson that I found it difficult to strike the right pace and tone of drama and excitement and with getting the class quiet and listening. The practical went smoothly and all students could see the DNA of their fruit, although kiwifruit and banana were definitely the most obvious and coagulated. Again, if I could go back in time again (and the lesson were a little longer) I would have everyone packed up and sitting back down before the dramatic reveal of the results! As it was we were running out of time, I rushed through the final slides of the gel electrophoresis and we had to scramble to pack up in time. Overall it was a fun way to introduce DNA and give students something to picture while we went on to learn more about it.
Class Site Content
WALT: Following instructions to extract DNA from fruit, to ascertain who killed Perry the Pear.
Learn where DNA is found inside of cells, and practice following instructions.
Creating a solution to the murder mystery by extracting DNA and comparing results "run through gel electrophoresis."
Share a recount of learning on their blogs.