Class Openers

Class Opener – Day 27 – Let the Dominos Fall!

We’re knee deep in arithmetic and geometric sequences right now, looking at explicit and recursive formulas for them. A television ad caught my eye the other day which seemed to fit the theme:

Lots of “cool” reactions from the room led to a discussion of “how did they do that?”.

Guess and Check!

Fortunately, after an evil eye from me, it turns out that student was kidding, and classes understood there had to be some intense planning going on, which is summarized some in this behind-the-scenes video:

But what is the relationship between the dominos? A healthy debate over a possible arithmetic sequence led to one student arguing that we would need many, many more dominos than in the video – if they were in an arithmetic progression. Next, we’ll look at the heights and see if we can come up with a plausible geometric model for the domino progression. A good kick-off to a Friday class!


By Bob Lochel

HS Math Teacher. Hatboro-Horsham School District, Horsham, PA.

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