Today my 6th graders created Stratification in a bottle. We used
ash, kitty litter, soil, baby cereal, rice, beans, and other materials to
represent different times in Geologic History- as life began, extinctions
occurred, and renewal started. Each table was given cups of different 'strata'
materials. As I read the story aloud- they listened, and I paused after each
section for them to be able to add their materials to their bottles.
Story
Around 4.5 billion years ago the
earth was just hot rocks, minerals, and molten lava. We have no evidence
of life on Earth.
Add 1 tsp of Lifeless Earth into
your bottle
The earth slowly
cooled and liquid water covered most of the earth. Life evolved in the
sea around 3.5 billion years ago. The first life was bacteria and
scientists have found chemical evidence of bacterial life. After millions
of years, the first bacteria gained the ability to photosynthesize and created
the first free oxygen in the atmosphere.
Add 1
tsp of Bacteria to your bottle.
Life continued to
evolve in the oceans and diversified into many different shapes and
sizes. Many had shells and shells break up into small crystals, making
sand.
Add 1 tsp
of Ocean to your bottle.
Life eventually moved
to land, starting with plants, then later animals.
Add 2 tsp of
Plant Life to your bottle.
Sudden extinction
event- what material do you think we should add here to distinguish it from the
previous strata?
Then animals evolved
into a wide range of flying, crawling and climbing animals.
Add 10 each
Small Organisms to your bottle
Sometimes many
volcanoes would erupt at once, spewing ash into the skies and leaving the land
without the ability to support life.
Add 1 tsp of
Volcano and Fire.
And 1 tsp of
Lifeless Earth
The sea levels would
rise and cover the land with shallow oceans.
Add ½ tsp of
Ocean.
Oxygen levels in the
atmosphere increased and that allowed very large plants and very large animals
to evolve.
Add 1 tsp Plant
Life
and 4 Large
Organisms.
Sometimes a great
earthquake would rattle the earth. Gently knock your bottle a bit
sideways. At least once a great asteroid hit the earth causing
tremendous heat to kill some of the largest dinosaurs and spewing dust into the
atmosphere, blocking out the sun. Without the energy from the sun, plants
died, the large herbivorous dinosaurs, then the large carnivorous dinosaurs did
not have anything to eat.
Add ½ tsp
Asteroid.
Add ½ tsp
Volcano and Fire.
Eventually the earth
recovered, and plants and smaller animals thrived again.
Add 1 tsp Plant
Life
and 5 each of
Small Organisms.
Students had a fun time using funnels and adding different layers
into the bottle. Eruptions, extinctions, and era's oh my! What a fun day.
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