## Thursday, April 24, 2014

### Sphero: Polygons and Angles This is my second post in a series that will cover the educational lesson plans from the SPRK (Schools Parents Robots Kids) program.  In this lesson (designed for 4-5th graders) students will use Sphero to draw polygons and learn the relationship between heading angles and the number of sides in a polygon where all sides are equal.

*All data will be recorded by the student in the downloadable worksheet.

### Objectives (aligned to Common Core Math Standards)

• Learn about how the Sphero has a heading that goes from 0 to 360 degrees, and it determines in which direction it will roll.
• Students will write a program to make the Sphero draw a square, where each side of the square is a different color.
• Students will write a program to make draw a triangle, determining the heading angles from clues.
• Students will write a program to make draw a pentagon, determining the heading angles from a formula.

### Square

To start out the students will create a new macro using the free MacroLab app.  They will do this adding a color (RGB) command and then a roll command.  They will then repeat this step but w/ a 90 degree heading.  Again they will repeat this step w/ a 180 degree angle and finally a 270 degree heading.  Of course it is vital that students test these commands by running them to see how the Sphero reacts and adjust accordingly.

### Triangle

After having the Sphero draw a square they will draw a triangle.  After discussing why 360 degrees in a circle is divided up into 4 equal parts at 90 degree angles forms a square students will divide 360 degrees into 3 equal parts at 120 degrees.  Students will create a new macro and add a color (RGB) command w/ a roll command of a heading of 0.  They will repeat this step w/ a 120 degree heading and a stop command delay of 255.  Finally, they'll add another macro w/ a color (RGB) command, w/ a 240 degree heading, and a stop command w/ a delay of 255.  Finally, they modify their macro by adding stop/delay commands at the end of each side of triangle.

### Fun Challenge

This challenge is to see if the students have understood the concepts by having a Sphero draw a pentagon.  They'll need to figure out that a pentagon has 5 sides and heading directions will be 360 / 5 = 72 degrees.  Their macro will need to look like this...
1. Add a RGB command for red and roll w/ heading of 0.
2. Add a RGB command for green and roll w/ heading of 72.
3. Add a RGB command for blue and roll w/ heading of 144.
4. Add a RGB command for yellow and roll w/ heading of 216.
5. Add a RGB command for purple and roll w/ a heading of 288.