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Subject Hierarchy Taxonomy Explorer

An interactive network visualization that helps users understand how subject terms relate hierarchically when creating Dublin Core metadata for educational resources like MicroSims.

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Learning Objective

Students will classify subject terms at appropriate levels of specificity by exploring hierarchical relationships between broad disciplines and specific topics.

How to Use

  1. Explore the Hierarchy: The visualization shows three levels:
  2. Disciplines (blue, large) - Broad fields like Physics, Mathematics, Biology
  3. Domains (green, medium) - Subject areas within disciplines like Mechanics, Algebra

  4. Topics (orange, small) - Specific concepts like Projectile Motion, Quadratic Equations

  5. Click to Expand/Collapse: Click any node with children to expand or collapse its subtree

  6. Search: Use the search box to find specific subjects and highlight their path in the hierarchy

  7. View Details: Hover over nodes to see descriptions and example usage

  8. Change Layout: Toggle between hierarchical tree view and radial force-directed view

Key Concepts

Subject Specificity Levels

When tagging MicroSims with Dublin Core subject metadata:

  • Discipline level is too broad for precise discovery ("Physics")
  • Domain level is good for categorization ("Electricity")
  • Topic level is best for specific learning resources ("Ohm's Law")

Best Practice: Use Multiple Levels

A well-tagged MicroSim includes subjects at multiple levels: 

1
"subject": ["Physics", "Electricity", "Ohm's Law", "Current", "Voltage"]

This ensures the resource is discoverable whether users search broadly or specifically.

Lesson Plan

Duration

10-15 minutes

Activities

  1. Exploration (5 min): Have students freely explore the hierarchy, expanding and collapsing nodes to understand the structure

  2. Classification Exercise (5 min): Give students a MicroSim description and ask them to identify appropriate subjects at each level

  3. Discussion (5 min): Discuss why using multiple specificity levels improves discoverability

Assessment

Ask students to: - Identify the appropriate discipline, domain, and topic for a given MicroSim - Explain why both broad and specific subject tags are valuable

References