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.