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TerraPrinter Classroom · Worksheet · Ages 9–14

Volcanoes: shape tells the story

Name Class Date

Volcanoes come in different shapes. The shape depends on the kind of lava and how the volcano erupts. Use the 3D models of Mount Fuji, Mauna Loa and Mount St. Helens to compare them.

You need these models

Open a link in a web browser to see the model in 3D, or use the printed model from your teacher.

  1. Put the Mount Fuji and Mauna Loa models side by side. Which one has steeper sides? How can you tell?

  2. Use a ruler. For each model, measure how high the summit is above the edge of the print, and the distance from the summit to the edge. Then divide rise by distance.

    VolcanoRise (mm)Distance (mm)Rise ÷ distance
    Mount Fuji
    Mauna Loa

  3. Mount Fuji is a stratovolcano, built from layers of thick, sticky lava and ash. Mauna Loa is a shield volcano, built from runny lava. Explain why runny lava builds a wider, flatter volcano.

  4. Find the crater of Mount St. Helens. One side is missing. Which direction does the open side face? (North is at the top of the map in the app.)

  5. Before 1980, Mount St. Helens was about 2,950 m tall. The eruption took about 400 m off the top. About how tall is it now?

  6. Sketch a side view of a stratovolcano and a shield volcano. Label: summit, crater, steep slope, gentle slope, layers of lava and ash.

  7. If you lived near one of these volcanoes, where would you build a town? Where would you avoid? Give one reason.

terraprinter.com/classroom/worksheet/volcanoes/

TerraPrinter Classroom, CC BY 4.0: free to copy and adapt with credit.

TerraPrinter Classroom · For the teacher

Answer key: Volcanoes: shape tells the story

Learning goals

Answers

  1. Put the Mount Fuji and Mauna Loa models side by side. Which one has steeper sides? How can you tell?Mount Fuji. Its sides rise quickly to a narrow top. Mauna Loa rises slowly over a long distance and looks like a wide, low dome. Both models use the same area, size and exaggeration, so the comparison is fair.
  2. Use a ruler. For each model, measure how high the summit is above the edge of the print, and the distance from the summit to the edge. Then divide rise by distance.Numbers depend on the print, but Mount Fuji's rise ÷ distance should be clearly bigger than Mauna Loa's. For reference, Fuji's upper slopes are about 30° or more; most of Mauna Loa's slopes are under about 10°.
  3. Mount Fuji is a stratovolcano, built from layers of thick, sticky lava and ash. Mauna Loa is a shield volcano, built from runny lava. Explain why runny lava builds a wider, flatter volcano.Runny lava flows a long way before it cools and hardens, so it spreads out in thin, wide sheets. Sticky lava and ash pile up close to the vent, which makes steep sides.
  4. Find the crater of Mount St. Helens. One side is missing. Which direction does the open side face? (North is at the top of the map in the app.)North. On 18 May 1980 the north side of the mountain slid away in a huge landslide, and a sideways blast burst out of that side, leaving a horseshoe-shaped crater open to the north.
  5. Before 1980, Mount St. Helens was about 2,950 m tall. The eruption took about 400 m off the top. About how tall is it now?About 2,550 m (the summit is now 2,549 m).
  6. Sketch a side view of a stratovolcano and a shield volcano. Label: summit, crater, steep slope, gentle slope, layers of lava and ash.Stratovolcano: tall, narrow cone with steep sides and alternating layers of ash and lava. Shield volcano: wide, low dome with gentle slopes made of many thin lava flows. Both have a crater at the top.
  7. If you lived near one of these volcanoes, where would you build a town? Where would you avoid? Give one reason.Answers vary. Good answers keep away from the valleys and low ground that lava flows and mudflows follow, and away from the side a blast or landslide could come from. Upwind is better for ash.

Before the lesson

Print the models at 150 mm wide, 0.2 mm layers, 10–15% infill, no supports. Fuji and Mauna Loa are set to the same 25 km area, the same 150 mm size and the same 1.5× vertical exaggeration, so their slopes can be compared fairly. Measurements on the sheet assume the 150 mm size. Students' measured answers will vary a little with how they measure. Discussion questions and a hands-on activity for this topic: terraprinter.com/classroom/#volcanoes