Particle Detection

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By tossing, collecting, and sorting beanbags, learners understand how the IBEX spacecraft uses its sensors to detect and map the locations of particle types in the interstellar boundary. Learners model the collection of particles called Energetic Neutral Atoms (ENAs) by the Interstellar Boundary Explorer (IBEX). If you need an audio version of this material, the file is compatible with screen reading software such as Adobe Acrobat Reader.

Quick Guide

  • Preparation Time: 10 to 30 minutes
  • Learning Time: 30 to 45 minutes
  • Estimated materials cost: Over $20 per group of students
  • Age Range: Ages 11 - 18
  • Language: English

Materials List (per group of students)

  • 4 medium-sized buckets/boxes painted or covered with colored paper and numbered as indicated in the Set-up Diagram (p2 of PDF)
  • 2 pieces of stiff cardboard or lids to cover the buckets when not in use
  • 50-100 small beanbags (red, orange, yellow, green and blue), a cheaper alternative may be balloons filled with sand or rice.
  • masking tape
  • IBEX spacecraft poster or picture
  • 16 clear tubes or cylinders (e.g. graduated cylinders) that are big enough in width to accommodate the beanbags numbered as in the diagram
  • an area at least 10ʼx10ʼ

Informal Category

  • Physical Activity


  • Earth and Space Science
    • Astronomy
      • Probes, Satellites and Spacecraft
    • Solar System
  • Engineering and Technology
    • Technology
      • Information and Communication
  • Mathematics
    • Data Analysis and Probability
      • Data Collection
      • Data Representation
  • Physical Sciences
    • Energy
    • Structure and Properties of Matter
      • Elementary Particles and Nuclear Physics
  • The Nature of Science
    • The Scientific Process
      • Gathering Data
  • The Nature of Technology
    • Technology and Society
      • Impacts of Technology
Place and Time


  • IBEX Mission Launch Date
  • Date: October 19, 2008

To use this activity learners need to

  • see
  • see color
  • be mobile
  • touch

Learning styles supported

  • Involves teamwork and communication skills
  • Involves hands-on or lab activities
Includes assessments for student learning:




All Rights Reserved, NASA,

Funding sources

  • NASA



Detectors designed for modern

Detectors designed for modern accelerators are huge, both in size and in cost. The term counter is often used instead of detector, when the detector counts the particles but does not resolve its energy or ionization.