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Title:  Geologic Time - When Was Coal Formed?
Level:  Middle/Secondary
Day/Time:  One to two days, one day for research, one day to construct time line.
KERA Goals:  2.4, 2.6, 2.9, 5.3, 6.16


The student shall construct a time line of geologic periods and label the major happenings in each.  The student should pay attention to the climate and conditions during the coal forming periods.


  1. Adding machine tape 5 meters long
  2. Metric ruler
  3. Tape

Background Information:

The students should have a general knowledge of epochs, periods and eras.  They should make a chart similar to the one provided.  Research can be done ahead of time by dividing the class into groups and give each group a period to research.  This information can be added to the chart.  Students should work in groups of two to construct the time lines.  Be sure to have a large area (a long hallway is good) in which to work.


  1. Measure and cut off a strip of adding machine tape that is 5 meters long. One meter = one billion, one centimeter = ten million, and one millimeter = one million.
  2. Tape adding machine tape to a flat surface where you can work easily.
  3. Draw a line near the end of the tape. This will be the beginning of the earth. Measure 4 meters from this mark and draw a line. Label it “End of Precambrian Time.” Starting at this line, mark the distance that will represent the end of the Paleozoic Era. Label it “End of Paleozoic Era.” Go back and divide the part of the tape representing the Paleozoic into correct lengths representing each period of this era. Label each with the correct name. Do the same with each era and period. Go back and label the main events in each era.


EraPeriod Length in years Length on tape Major Events
Total Length  4 billion   
Paleozoic Cambriam
70 million
70 million
35 million
50 million
25 million
40 million
55 million
Total Length  354 million   
Mesozoic Triassic
35 million
54 million
71 million
Total Length  160 million   
Cenozoic Tertiary
63 million

Activity developed by:
Beverly Bowers, Mannington Middle School, Fairmont, West Virginia and
the American Coal Foundation