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In this invention challenge activity, learners see how many objects they can grab with a homemade "bionic" arm. Learners will follow the design process to build a grabber that can reach at least two feet, develop a way to open and close the grabber’s jaw, and figure out how to connect the “jaw” to a stick. Educators can use this activity to introduce learners to the design process as well as simple machines (lever, fulcrum).

Quick Guide

Preparation Time:
Under 5 minutes

Learning Time:
30 to 45 minutes

Estimated Materials Cost:
$1 - $5 per student

Age Range:
Ages 8 - 14

Resource Type:

English, Spanish

Materials List (per student)

  • 4 brass fasteners
  • corrugated cardboard
  • hole punch
  • objects to pick up (e.g., tennis balls, cotton balls, plastic soda bottles, and paper cups)
  • 2 rubber bands
  • sandpaper
  • scissors
  • string
  • tape (duct or masking)
  • 4 toothpicks
  • 4 wooden skewers
  • yardstick (or long paint stirrers for 5-gallon buckets, a thin wooden slat, or lath 2–3 feet long)


  • Engineering and Technology
    • Engineering
      • Bioengineering/Biomedical Engineering
      • Mechanical Engineering
    • Technology
      • Medical Technology
  • Life Sciences
    • Human Body
      • Skeleton
      • Muscles and Skin
    • Human Senses and Perception
      • Touch
  • Physical Sciences
    • Energy
      • Work and Machines
    • Motion and Forces
      • Machines
  • The Nature of Science
    • Science as a Career
  • The Nature of Technology
    • Technology and Society
      • Impacts of Technology
    • The Design Process
      • Research and Development
      • Invention and Innovation
      • Problem Solving
      • Troubleshooting and Maintenance


To use this activity, learners need to:

  • see
  • read
  • touch

Learning styles supported:

  • Uses STEM to solve real-world problems
  • Involves hands-on or lab activities


Components that are part of this resource:

This resource is part of:

Access Rights:

  • Free access


Source Collection

  • Design Squad Nation


Funding Source:

  • National Science Foundation, 0810996