Deep Time and You
Students make time lines showing significant events in Earth's history and their own lives.
- Students will be able to construct a time line.
- Students will begin to comprehend the magnitude of geologic time.
The Earth is about 4.5 billion years old, a number too large for people to conceptualize. If we were to shrink the Earth down to the size of a basketball and compress those 4.5 billion years into a few hours we would be able to observe radical changes. Continents would race around the globe, sink beneath the sea, rise up again, smash into other continents, build mountains, and erode back into the sea. Volcanoes would continually erupt and then quickly be weathered away. An astounding array of life would evolve and most of it would pass into extinction seconds later. Asteroids would occasionally slam into Earth. Indeed, the Earth would look like an extraordinarily dynamic little sphere before us.
But from our reference point, change of this magnitude is hard to appreciate. Yet if we begin to grasp the immensity of geologic time, we can begin to recognize the changing nature of Earth.
- Adding machine tape (3 or 4 inches wide by about 100 feet)
- Pencils, pens, crayons
- String or yarn
- Use of a large indoor wall while your class is studying about Craters of the Moon
Students will construct time lines using adding machine tape. Completed time lines will be displayed on a wall for reference during the weeks you are studying Craters of the Moon. In subsequent Cultural History and Ecology units, new time lines will be added to the existing ones on the wall. Time lines of different scales will be linked together with string or yarn to show temporal relationships. For example,
Part 1 - Personal Time Line
Have the students make a time line describing events in their own lives.
- Give each student a strip of adding machine tape about two feet long.
- Have them draw a straight line down the length of the tape.
- On the right side have them write "present."
- If the student is 10.5 years old, have them write "11 years ago" at the far left side of the tape.
- Then, let them divide the time line up into 11 equal increments.
- Finally, have them fill in significant parts of their life with text and pictures. Label it "Your Name's Time Line." For example,
- Save time line for future use.
Part 2 - Age of Earth Time Line
Have the students make a time line showing the age of the Earth.
- First, discuss the size of a billion. Quiz the students on what they were doing 10, 100, 1,000, etc. seconds ago. Let them guess; then tell them how long the time was in minutes, days, or years. They will be astounded at the size of a billion:
|10 seconds ago?
|100 seconds ago?
|1,000 seconds ago?
|1,000,000 seconds ago?
||(11. 5 days)
|1,000,000,000 seconds ago?
- Tell them the Earth is about 4.5 billion years old.
- Cut as long a piece of adding machine tape as your wall will accommodate.
- Have 2-3 students afix the time line near the bottom of the wall (other time lines will go above it) and mark off 5 equal lengths. Label the marks from left to right "5 billion years ago," "4 billion years ago," and so on. Label it "Earth's Time Line."
- At the 4.5 billion year old mark, write "the Earth is formed." Divide the most recent billion year division into 10 equal, 100,000,000 year increments.
- Later, your class can add more information to this time line.
Part 3 - Craters of the Moon Time Line
Have students make a time line showing events at Craters of the Moon.