## Objectives

Students develop a robot that can draw squares with a laser pointer. They are challenged in relation to their understanding of the connection between the area and side length of squares. In the tasks, students use reasoning to reach possible solutions while simultaneously documenting their work. The lesson can be carried out in connection with the lesson “Perimeter and squares.”

## Planning

It is a prerequisite for the lesson that students are familiar with squares, perimeter and area.

## Materials

• Fable robot
• Laser pointer
• PC with Fable software installed
• Pen and A3 paper

Duration: 2 lessons

## Learning activities

Students work in groups of two. Each group receives a copy of the assignment sheet.

Students develop code for Fable to make the joint module draw squares with a laser pointer. Students document their square by drawing it. To do this, they can use a sheet of paper as the work surface for the laser pointer. Students mark each corner point (laser dot) and draw the figure by connecting the points with lines. Students will probably realize that they need to include pauses in their code in order to have time to mark the points on the paper.

Once students have constructed a square, task 2 asks students to use Fable to construct a new square with an area that is four times as large. The idea is for students to discover the mathematical relationship between the side length and area of a square – i.e. that when the side length is doubled, the total area becomes four times as large.
If the lesson is carried out together with the lesson “Perimeter and squares,” students can be asked to examine what kinds of relationships they can find in the two tasks.

This could for example be:
If the side length of a square is doubled, the area becomes four times as large and the perimeter becomes twice as long.

## Evaluation

Students present their work to another group. In the presentations, students share their results and code.