Engineering an Outdoor Classroom Renovation


Problem Statement: Second grade students from an urban school become aware that the school’s outdoor classroom space was almost never used in its current state.

Design Goal: To build a large, three-dimensional, interactive, number line in the outdoor classroom space that could be used for math learning.


The number line should

  • Be big enough so that its length equals 10 students standing close to each other,
  • be able to teach the lower grades and 2nd grade students,
  • look nice and neat,
  • be strong and waterproof,
  • be designed such that could be build without a handyman


  • Cannot exceed a certain fixed budget provided for materials

What solution did the students design?

The students worked in small groups. Each of the group focused on different aspects of the number line. Each of the small groups built different components that were at the end assembled together to make a 3-D, interactive, portable number line. A few jobs with drilling holes in PVC pipes were done by the classroom teacher while taking care of safety of the students around. Materials used by the students included: PVC pipes and connectors, Velcro (to hang the pipes to supports, making it portable), hooks, pipe cleaners, plastic Dixie cups and sand (make weight line, strings of different lengths (represent increase and decrease of length) plastic card holders (for number display), a hook, Velcro and cardboard (to make a slider) and stickers (make the display look fun and colorful).

Math & Science Content Connections

  1. Number line
  2. Weight and heaviness
  3. Waterproof materials (material properties)
  4. Simple linear equations (y cm(next thread length)= x cm(previous thread length)+2 cm)
  5. Units of measurements
  6. Engineering design process