- Topics: Logic, Puzzles: Book: Still More Stories to Solve by G. Shannon, stories 6-8.
- Topics: Optical Illusions, Geometry: We did several activities from The Usborne Optical Illusions Activity Book, by S. Taplin. The first activity was about coloring a diamond grid — the well-known illusion about two different ways to see a pattern of cubes. The second activity involved a pattern with several rows of arrows, odd rows point left and even rows pointing right — once colored, it can either look like, say, red arrows pointing right on a blue background, or blue arrows pointing left on a red background. The third activity was a circle of dots which when connected in the specified way generated a circular hole in the middle in the shape of a circle. I extended this activity by showing the kids how to draw a line drawing of a star: Draw a cross on a sheet of graph paper, and then draw a line from (0, X) to (12 – X, 0) for all X.
How Did It Go?
We had all five kids this week. I realized 15 minutes before circle we should have done an activity involving Pokemon, and indeed there was a lot of talk about Pokemon Go during circle while the kids were coloring. We’ll definitely do something about Pokemon soon.
Still More Stories to Solve
The first puzzle was a variant of “This sentence is a lie.” — awfully hard for an 8-year-old to guess. The second was about a king saying “Don’t do X until you see my face” (meaning, “until we meet again”) and then someone sees the king’s face on a coin so they do it earlier. With some clues the kids realized that people’s faces were on money, and then they figured out the answer exactly. The last one also went pretty well, they needed a lot of hints but they figured it out.
The first two only went ok, the kids were fine coloring the pictures, but then they weren’t impressed by the illusion at all. For the cube one, I’m not sure if they were actually seeing it both ways, or if they were just uninterested; it’s very hard to tell the difference. Most kids said something similar for the arrows: they said “They go both ways.” One kid was quite sure that they were blue arrows going left, because the top and bottom row were red, so red looked like the background. I added a row of blue arrows to the top, and then they said that the arrows didn’t go either way.
The third activity (circle of lines) was fine, not too hard and a nice-looking result — but still not that much excitement. However, the star-shaped pattern was much more interesting to them. It was tricky to do correctly — many of the kids repeatedly forgot to move one of the endpoints of the line. In the end, all of the kids asked for me to make another cross on grid paper so they could take it home and try it again. At first, I was doing the wrong thing — connecting (0, 12) to (1, 0) when I should have connected (0, 11) to (1, 0). One very interesting thing about this activity is that there are several closely connected curves. Besides the one we did, there’s also one where the length of the line you draw is constant (draw all possible lines of length 12 connecting the X axis to the Y axis), and there’s also connecting (0, X) to (1/X, 0), which makes a hyperbola.