Monitoring Volcanoes · seed 1 · A4, ink-friendly. The answer key prints on its own page for grown-ups.

Watching a Volcano for Warning Signs

Science · Volcanoes & Earthquakes · ages 9-11
Name ______________________   Date ____________

  1. What tool might scientists use to notice the ground swelling on a volcano?

    • A thermometer for people
    • A tiltmeter or GPS sensor
    • A rain gauge

  2. Which of these is a warning sign scientists watch for before an eruption?

    • Rising gas from the volcano
    • The color of nearby flowers
    • How many tourists visit

  3. Volcanologists usually look at just one clue, like gas, to decide if a volcano is risky.

    Circle one:   True   False

  4. Why can't scientists give an exact date and time for an eruption?

    • Because magma is hard to predict exactly
    • Because volcanoes never actually erupt
    • Because they haven't invented any instruments yet

  5. A volcano shows rising gas, but the ground has not swelled and there are no small quakes. What should scientists do?

    • Announce an eruption is happening today
    • Ignore the gas reading completely
    • Keep watching for more signs before deciding

  6. The graph shows small earthquakes counted per week before an eruption. How many were counted in Week 3?

    Week 13Week 26Week 311

    Answer: ______________

  7. A volcano shows small earthquakes increasing and gas rising, but scientists still say the risk is uncertain. Why, even with two signs present?

    • Signs only matter once there are at least five of them
    • Two signs always mean an eruption happens tomorrow
    • More evidence raises concern, but it still can't remove all uncertainty

  8. A news report says, 'Scientists are 100% certain the volcano will erupt exactly next Tuesday at noon.' What is wrong with this statement?

    • Volcanoes cannot be predicted at all, ever
    • Some uncertainty always remains
    • Tuesday is never a day volcanoes erupt
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Answer key

For grown-ups. Fold this page away before handing over the rest.

Watching a Volcano for Warning Signs W1-mt_ZRoQVXf_aD-s1

  1. A tiltmeter or GPS sensor · Tiltmeters and GPS sensors catch tiny changes in the shape of the ground.
  2. Rising gas from the volcano · Gas, like sulfur dioxide, often increases as magma moves closer to the surface.
  3. False · They combine gas, ground shape, and earthquakes together for a fuller picture.
  4. Because magma is hard to predict exactly · Even with good instruments, the exact path and timing of magma stays uncertain.
  5. Keep watching for more signs before deciding · One clue by itself is not enough. Scientists watch how signs change together over time.
  6. 11 · The bar for Week 3 shows 11 small earthquakes, more than the weeks before it.
  7. More evidence raises concern, but it still can't remove all uncertainty · Combining evidence helps judge risk, but it never makes the outcome certain.
  8. Some uncertainty always remains · Scientists can raise alarm levels based on evidence, but they can't promise an exact moment.
Worksheet · LightMySky