For my second STEAM activity, I decided to teach a magic trick. Once again, Numberphile was the inspiration. This time, with Matt Parker.
In the nine card version of the trick, you only deal out the deck twice before the reveal, which makes things easier to remember. This is good for the students if they want to perform some magic for their parents later, and good for the presenter since there's less chance of screwing up.
For the STEAM activity, I asked the class who liked magic (everyone). Then I asked who wanted to learn a magic trick (everyone). I gathered the students around me, and told them I had a card trick that was based on mathematics. I did the trick for them, picking a random student to be the person being tricked. Then I showed them how the trick is done by replacing the "chosen" card with a red suited card, and having all the other cards be black. I sorted the deck before the activity so I could just grab nine cards off the top of the deck for the first demonstration, then deal off nine more cards to get the imbalanced set.
As a total aside, the fact that I could deal off nine cards and have only one of them be red turned out to be pretty impressive in and of itself. Preparation is everything. In the cooking world, it's called mise en place. Back to the story.
Once we ran through how to do the trick a couple times, I had the students pair up and gave everyone nine cards (from pre-shuffled decks), and told them to switch off doing the trick to each other. I never explained the mathematics behind the trick unless I was specifically asked. The next 20 minutes or so was the students practicing their magic, with me, the teacher, and my son walking around helping out.
At the end of the activity, as we were saying our goodbyes, I asked the students if they wanted to see one more trick before I left. They rushed up into a semicircle around me, and I performed the following on the teacher with all the students watching.
