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The Toilet Paper Timeline
A history of Earth…One square at a time
The earth is roughly 4.6 billion years old. That is 4,600,000,000 years, or in scientific notation,
4.6 x 109 years. Life first originated in the oceans 3.4 billion years ago. The dinosaurs died out
65 million years in the past. Human recorded history stretches back 10,000 years in time.
These numbers are hard to visualize and difficult to compare. One way to put these large
numbers into a form that can be comprehended is to use a scale. The scale that we will use is
squares of toilet paper. You'll need 46 sheets of toilet paper, a long hallway, and markers.
Unroll the full roll of paper down the hallway. You will need to keep the time to scale. To do
this, make sure you determine how many years each square is, and how large your square is
using a ruler in case you need to subdivide it.
Once the paper is completely unrolled, you can use this table or the one of pg. 439 in your book
to mark the important events in earth's history at the appropriate points on the toilet paper.
Furthermore, you need to add 6 points of your choice (they can be virtually anything!) to the
timeline.
Years Before
Present
Important Events in Earth History
4.6 billion yrs
earth is formed, along with the other planets
3.7 billion yrs
earth's crust solidified
3.5 billion yrs
first life appears in oceans
3.25 billion yrs
photosynthesis begins in oceans
2.4 billion yrs
oceans contain significant amounts of oxygen
1.9 billion yrs
first cells with nuclei appear in oceans
0.65 billion yrs
first multicellular organisms appear
0.5 billion yrs
first land plants with inner vessels
250 million yrs
mass extinction of 99% of all life
245 million yrs
Age of Dinosaurs begins
150 million yrs
Pangaea breaking up; continents drifting apart
65 million yrs
Age of Dinosaurs ends, mass extinction of 70% of all living
things
3.5 million yrs
First proto-humans appear, in what is now Africa
100,000 yrs
First Homo sapiens appears
10,000 yrs
All of recorded human history begins
You should also have the following time periods included with dates and one picture to represent
it:
Cambrian
Ordovician
Silurian
Devonian
Carboniferous
Permian
Triassic
Jurassic
Cretaceous
Paleogene
Neogene
Quaternary