|
Authors:
Godfrey Nowlan, GSC
Beverly Ross, Rundle College Junior High School
An Exercise In Understanding Geological Time
Background:
Geologists have been able to estimate the age of the Earth by studying the rocks and minerals and by dating radioactive isotopes contained within them. The current theory is that the earth is approximately 4.6 billion years old, but that is subject to change as new dating methods are being discovered. The oldest mineral actually dated is a piece of zircon that is 4.3 billion years old. Since its birth, our Earth has been in constant turmoil and motion. Continents have split and moved, and the crust continues to shift today. There have been several mass extinctions, islands have been born and buried, and climates have changed drastically. In this activity, your students will make a time-line from the earth's birth to present day that they can actually walk along in order to get a better idea of how old our planet really is.
Materials:
- 50 metres of adding machine paper (may need two rolls)
- Metre stick
- Marking pen
Procedure:
The 50 metres of paper (46 metres exactly) will represent the 4.6 billion (4600 million) years that the earth has been around. This is a scale of one cm equals one million years. Major events in the earth's history are marked onto the roll of paper. The following table gives you the names and dates of the geologic eras, as well as major events and life forms. It also tells you how many centimetres you should have between events on your time-line. Children can make pictures of the events on the paper. This time-line includes only major events, but you may want to have the children do some research to add on other dates such as when certain dinosaurs or other fossilized creatures appeared.
HINT: You will need a LOT of wall space to display your time line (hallway).
Larger version of image
| 
