# A Living Math Treasure

I happened upon this book on one of our library trips and decided to use it for one of our casual Friday lessons. Let me just tell you, this was such a fun math lesson to teach!

The Fly on the Ceiling: a Math Myth tells a humorous story of Rene Descartes and introduces the concept of Cartesian coordinates. The tale is very engaging and had the kids’ attention immediately. A great philosopher who is extremely messy has a problem: he can’t find anything! He takes a walk to think through his problem and is thinking so hard he steps off a dock into the ocean. Soaking wet and sick with a cold, he goes home to bed. The next day, as he lays in bed recuperating, he notices a fly on the ceiling and decides to find out if the fly ever lands in the same spot twice. With a piece of charcoal, he sketches a grid onto his ceiling and with the coordinates he charts the fly’s landings. Then, in the midst of his fly observations, it suddenly occurs to him that he could chart his belongings and solve his problem of losing things. So he calls a neighboring painter to paint the grid on his floor, positions his possessions over the dried paint, charts where everything is based on his coordinate system, and hangs the chart on the wall.

The book admittedly is not entirely factual. But that, too, was a great lesson. I talked with the kids about what details they thought might be true and what parts of the story were probably pretend. They could pretty easily decide between the fact and the fiction.

Next, we plotted our own Cartesian coordinates.

And pulled out our counting bears.

The book used numbers for both sets of coordinates, so we did too. But on hind sight, it would have been easier for them to have had a set of letters and a set of numbers for the coordinates. Nevertheless, the story and the lesson was highly entertaining and educational. What more could you want out of math!

For more fun with cartesian coordinates, check out this link.