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Activity: Timeline of Earth
NGSS Science and Engineering Practices
NGSS Disciplinary Core Ideas
Table of Contents


  • Table 7.4.
  • Meter stick or measuring tape
  • Rope or yarn (at least 5 m length)
  • Masking or painter’s tape
  • Markers
  • Index cards



  1. Cut rope for a timeline
    1. Measure out and cut 4.6 m of straight rope or yarn.
    2. This 4.6 m length of rope will represent the entire 4.6 billion years since the formation of Earth.
    3. Wrap the two rope ends with masking tape to prevent fraying.
  2. Label one end of the rope as “present day” and the other end as “4.6 billion years ago.”
  3. Use the meter stick to measure 0.5 m from the present day end of the rope.
  4. Use masking tape to label this 0.5 m point as “500 million years ago.”
  5. Continue measuring and labeling rope segments, in 500 million increments, until the end of rope.
  6. Prepare event index cards
    1. Complete the missing cells in the list of several major events in Earth’s history (Table 7.4.).
    2. On one side of a blank index card, write the name of the event and a brief description of it.
    3. Write the event date on the opposite side of the index card.
  7. Attach event index cards to the timeline at the appropriate locations.
  8. Present your timeline to your classmates.


Activity Questions
  1. If the entire 4.6 m-long rope represents 4.6 billion years, how much time is represented by the following lengths:
    1. 10 cm
    2. 1 mm
  2. The term “Precambrian” refers to the period of time before the Cambrian Explosion around 542 million years ago.
    1. What is the significance of the Cambrian Explosion in terms of life on Earth?
    2. How does the length of Precambrian time compare to amount of time after the Cambrian Explosion?
  3. The Great Oxygenation Event was the sudden increase in oxygen gas (O2) concentration in the atmosphere, beginning around 2.5 billion years ago (for more detail, see Building Blocks of Life).
    1. What earlier evolutionary event likely caused the Great Oxygenation Event?
    2. How do you think organisms survived before the Great Oxygenation Event in a world with low oxygen gas concentration?
  4. The midpoint of the timeline is 2.3 billion years ago (2.3 m from either end). Use your own words to describe life on Earth before this point on the timeline.
Exploring Our Fluid Earth, a product of the Curriculum Research & Development Group (CRDG), College of Education. University of Hawaii, 2011. This document may be freely reproduced and distributed for non-profit educational purposes.