Sunday, June 29, 2014

Lesson 58 - Back to Geometry

There's been some time since our last computer lesson with my daughter. Meanwhile we've been doing a lot of other stuff together, like laying bricks, riding bikes, playing music and making concrete and food. She's asked for a computer lesson a few times, but it's been inconvenient at those occasions so we've ended up having quite a long break. 

And I think it's good. I've been having the feeling that she's pretty much reached the limits of what she can learn at her age, at least with the methods we've used. She's still a 5-year old after all.

Anyway, a few days ago Sanna Salo and her colleagues at Linja published a Koodikoulu (Code School) video on Youtube. My daughter is the narrator on the video :) I think the publication of the video inspired her to ask me for a computer lesson today.

Today my plan was to practice problem solving from the point of view of Geometry. We started with basic shapes. She easily drew a triangle (kolmio in Finnish) and a square (neliö). She wasn't quite happy with some of the lines so I thought her to use a ruler. We also discovered that using an angle ruler (is that the right word?), you can easily make right angles (90 degrees!) and create a nice looking squares. Then she drew me another shape and I asked her if that's a square. She corrected me and told me that it's in fact a rectangle (suorakulmio).

She didn't think that squares are rectangles too, which they in fact are. And we agreed that a rectangle is a square if it's edges have the same length. Then we measured the lengths of her square to be almost exactly 3 centimeters each.

Then I showed on the paper how a turtle would draw a 90 degree circle segment and asked her to show what would happen if it repeated the same trick. She correctly showed how the turtle would complete the second segment. Then we repeated that until a whole circle was covered. And concluded that if you do 4 turns of 90 degrees each, you'll end up with the full circle.

Then we practiced splitting the circle (or a pie!) into 3 segments in the same way. You can see how it went in the picture above. Then we first concluded that if you split a pie into 4 segments, you'll get 90 degree angles. And when asked, she demonstrated me that when you split it into 3 segments, the angles are bigger. But how to calculate the angle?

At this point (30 minutes later or so) she was getting tired and her concentration was slipping. You can see that on the pictures too, I guess. So when we started doing the math (360 / angle) she was eager to get to the computer. So we had the computer calculate the angle of an equilateral triangle.


Big numbers for a 5-year old. Yet with my help she was able to parse the result into a word "satakaksikymment√§". 

And we managed to draw the equilateral triangle using Turtle Roy. A lot of giggling was involved. 15 minutes later, she's asleep.

And I think that geometry and turtle graphics are a fun way to learn programming.  Next time we'll hopefully return to the same subject and see how she can decompose a problem and formulate it as a computer program. Then recognize and eliminate duplication using the sequence and repeat commands.


  1. That was a fun lesson Juha! FYI an "angle ruler" is called a "set square", at least it is in British English anyway.

  2. Thanks Migwell! A set square it is then :) The actual instrument can be seen in the first photo too. I guess it's a "set square with a half-circle protractor" to be more precise. In Finnish, we call it "kulmaviivain".