Lesson Plan

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Lesson Plan
Grade: Date: 17/01/2026
Subject: Geography
Lesson Topic: Volcanic explosivity index (VEI)
Learning Objective/s:
  • Describe the components and scale of the Volcanic Explosivity Index (VEI).
  • Calculate an approximate VEI using tephra volume.
  • Analyse how VEI values inform hazard mapping and emergency planning.
  • Evaluate the limitations of the VEI in assessing volcanic risk.
Materials Needed:
  • Projector and screen
  • PowerPoint presentation with VEI scale diagram
  • Handout of VEI table
  • Calculator or spreadsheet for sample calculations
  • Whiteboard and markers
  • Printed case‑study sheets of historic eruptions
 Introduction:
Begin with striking images of recent volcanic eruptions and ask students what factors determine their impact. Recall prior learning on volcanic hazards and introduce the VEI as a tool to quantify eruption size. Explain that by the end of the lesson they will be able to compute VEI values and discuss their relevance to risk assessment.
Lesson Structure:
  1. Do‑Now (5'): Students match eruption photos to VEI categories on a quick worksheet.
  2. Mini‑lecture (10'): Present the VEI scale, its logarithmic nature, and key parameters using slides.
  3. Guided calculation (10'): Work through the sample 5 km³ tephra calculation together; students use calculators.
  4. Group activity (15'): In small groups, analyse a case study (e.g., Mount Pinatubo) to identify VEI, associated hazards, and emergency responses; record findings.
  5. Whole‑class discussion (5'): Groups share insights; teacher highlights limitations of the VEI.
  6. Check for understanding (5'): Exit ticket – write one way VEI informs hazard planning and one limitation.
Conclusion:
Summarise how the VEI provides a concise measure of eruption magnitude and its role in hazard mapping. Reinforce the importance of recognising its limitations when planning emergency responses. For homework, students complete a worksheet calculating VEI for two additional historic eruptions.