Fast and slow Earth changes · seed 1 · A4, ink-friendly. The answer key prints on its own page for grown-ups.

Rapid earth changes

Science · Space Systems & Earth's History · ages 7-8
Name ______________________   Date ____________

  1. Which of these happens slowly?

    • Volcanic eruption
    • Erosion
    • Landslide

  2. Which of these happens fast?

    • Earthquake
    • Canyon carving
    • Mountain building

  3. A volcanic eruption can happen in just a few hours.

    Circle one:   True   False

  4. You watch a video where the ground suddenly shakes and cracks appear in seconds. What kind of Earth event is this most likely?

    • Earthquake
    • Erosion
    • Mountain building

  5. A river has been cutting into rock for thousands of years, making a deep canyon. Is this a fast change or a slow change?

    • Fast change
    • Slow change
    • Not a change at all

  6. Which piece of evidence would best show that mountain building is slow?

    • A one-minute video of the ground shaking
    • Old maps and photos taken 100 years apart showing tiny height changes
    • A picture of lava flowing down a hill

  7. A scientist photographs a canyon in year one. She takes another photo 10 years later, then one more photo 10 years after that. How many years passed between the first and last photo?

    0102010 years10 more years

    Answer: ______________

  8. Leo says, "Earthquakes and canyons both change the Earth in just a few seconds." What is wrong with what Leo said?

    • Earthquakes take thousands of years
    • Nothing is wrong
    • Canyons form over a very long time, not seconds
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Answer key

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

Rapid earth changes W1-mt_ZJu8s-Q1xa-s1

  1. Erosion · Erosion wears away rock little by little, over a very long time.
  2. Earthquake · An earthquake shakes the ground in seconds. Canyons and mountains take much longer to form.
  3. True · Lava can burst out and flow in a short time, which makes an eruption a rapid Earth event.
  4. Earthquake · Sudden shaking and cracks that appear in seconds are signs of an earthquake.
  5. Slow change · The canyon formed a tiny bit at a time over thousands of years, so it is a slow change.
  6. Old maps and photos taken 100 years apart showing tiny height changes · Comparing photos taken many years apart shows tiny changes that add up slowly over time.
  7. 20 · 10 years plus 10 more years is 20 years. Comparing photos over that time shows how slowly the canyon changed.
  8. Canyons form over a very long time, not seconds · Earthquakes are fast, but canyons are carved slowly by rivers over thousands of years.
Worksheet · LightMySky