Balance Scale with Cubes (CS Unplugged teaching aid)

This model of a simple balancing scale was created to be used as a teaching aid in an “unplugged” activity regarding sorting algorithms. The material might be used in computer science or maths classes to give students the opportunity to deal with the problem of sorting by binary comparison “hands on”. If you can make use of the project in any other way: feel free to use, share or remix!

For the balancing scales base you will need two M3x15 countersunk screws to fix the top part to the bottom part. The balancing boom is held in place by the base.

The scale has a sensitivity of around 2g fresh from the print bed. It slightly decreases over time. My oldest print is still able to distinguish a weight difference of 3g. To make cubes of different weight you could simply try to modify the infill of each cube so that it differs around 2-3g. Since I use Prusament which is around 3 euro-cent per gram I ended up embedding 1 euro-cent coins to create a difference in weight. There are files for nine different cubes: From no embedded coins to 16 embedded coins. Each cube is 2 coins (4.6g) heavier than the previous one.

Material list for a single scale and nine cubes:

• 300g    PLA filament
• 2x         M3x15 countersunk screw
• 72x       1 Euro-Cent

Happy printing!