Last year I introduced geometric sequences via zombies in algebra 1. Because zombies = instant engagement. (I’m only half-joking here, by the way. Zombies really did equal instant engagement for 95% of my algebra 1 class last year.)
Here’s how it went down:
- Have the gross zombie on the projector when students are walking in.
- Answer “You watch The Walking Dead!?” affirmatively a bajillion times.
- Have students take out some paper to keep track of their work on.
- Demonstrate the concept of one zombie eating another zombie with fun role play. Explain that there are no zombie hunters for today’s simulation.
- Let students get to work answering the question on the board. Wait for someone to ask how many people live in Seattle. Go to slide two. Remember how great Seattle is.
- Let students continue working to answer how long until Seattle is completely zombiefied.
- Share results. Talk about how the growth rate is different from the linear models we’ve seen in the past.
- Switch to slide three. Take bets on how long it will take. Let students get to work.
- Share results. Talk about how everyone overestimated the time it would take because they didn’t really realize how quick “exponential growth” is. Show the graph on slide four. Talk about the two tails.
- Work through slide five, introducing notation.
- Have students suggest their own special zombie diets. Calculate the growth rate for these problems. (Zombies eat twice a day; zombies eat three times a day; zombies eat every other day. Zombies have to contend with zombie hunters.)
- Work through the Zombiepocalypse: Day 2 handout during the following class period.
The Day 2 handout might be a little too verbose for your needs. My algebra 1 students do well with lots of repetition and scaffolding. They were able to work through these two days well, and they also seemed to enjoy it.
I got the idea for this from someone out there on the internet, but I have no idea who. So if this looks like what you did, let me know so I can give you some credit.