Transcript Understanding Earth’s Changes Over Time

Understanding Earth’s Changes
Over Time
• How long is a million years?
• How can you measure a million?
• How does a million years compare with the
age of the earth?
• How would you proceed to make a time line
of the earth’s history?
Set up a scale following the directions and the
materials provided.
You will use a scale of:
1 millimeter = 1 million years
1 centimeter = 10 million years
1 meter = 1 billion years
Arrange your time cord so that the Present is on the
right as the three of you are facing it.
Using the diagram, mark the Geologic Eras on
the cord with masking tape and label.
MYA= million years ago
The white papers list Geologic and
Atmospheric events.
The green papers represent Biological events.
Using paper clips (watch demonstration)
arrange the events on the time cord. Notice
they will slide from side to side.
What do you notice about the GA and B
events as they get closer to the present?
Choose four B events and notice what GA
changes took place before the B event.
Could many of the B events have occurred
before the GA events preceding them?
Estimate:
What percent of Earth’s history shows evidence of
life according to the information given to you?
What percentage of Earth’s history for which there is
fossil evidence of the first humanlike animals?
What percentage of Earth’s history during which
dinosaurs lived?