If you live on the East Coast, chances are you’ve heard about this summer’s emergence of Brood II cicadas. Cicadas are winged insects that live underground most of their lives, sucking on the xylem (sap) from roots of trees. When the ground temperature 8″ below the surface reaches 64 degrees Fahrenheit, they will emerge and transform into their final adult form. They ascend into nearby trees, shed their skin one last time, grow wings, and set off to mate. Some species are annual cicadas and emerge every year. However, Brood II cicadas only emerge every 17 years and do so by the millions.
I teach at an Expeditionary Learning school, and teachers are encouraged to design curriculum through expeditions. Expeditions are rich units that engage students by investigating some compelling question(s). When I first read about the 17-year cicadas that would swarm North Carolina to Connecticut, it seemed like the perfect topic for my sixth grade math students.
We began the unit by Building Background Knowledge. First we listened to audio of the male cicada mating call. Students wondered what it could be, and then we showed them the associated video. We watched another video and discussed some cicada facts. Then students created a KWL chart of what they Knew and Wondered. (Later, we would add the other things the class Learned). Our guiding question was, “Where can we find mathematics in nature?”
The guiding question led us to explore why periodical cicadas only emerge every 13 or 17 years. We looked at the Sieve of Erastosthenes, prime numbers, factors and multiples. Then we practiced converting between fractions, decimals, and percents by creating surveys and representing the results in various ways. Students wanted to know if they could outrun a swarm of cicadas flying towards them, so we went outside and measured how fast different sixth graders could run. We explored measures of central tendency to see how fast an “average” sixth grader was. Finally, we looked at a cicada cookbook and practiced scaling recipes. Here is a link to many of the resources I used for this unit.
Students were disgusted and enthralled by the idea of eating cicadas! It was unfortunate that they made such a minimal appearance in New York City, especially after all of my build up. Fortunately, they did emerge in large numbers in Staten Island, so I took a trip to harvest enough Brood II cicadas to sate my students and colleagues! Here are some pictures of the preparation.
Anyone brave enough to eat one earned a button that became a badge of honor. (Thanks to Maurice Principe for designing them!)