Earth`s Crust - Teacher Resource
Earth`s Crust - Teacher Resource
Nature of Science Perspectives on
Teaching The Earth’s Crust
Central Themes of Cluster 4 – Planet Earth & Beyond
Central Themes of Grade 7 Cluster 2: The Earth’s
Historical Aspects associated with the “Living Earth”
Teaching of Science Applications
Lesson Critique & Planning
Electricity (A24) – Properties & Changes to Materials
Cluster 4: Planet Earth & Beyond Topics
Cluster 2 and Changes
Statistics – As If This Isn’t Enough!
Poorest country in the Western world – GDP per
capita 790 USD – per capita income $2 per day
Limited natural resources
Referred to as politically the most corrupt country in
Richest 1% control 60% of the country’s wealth
80% live in poverty
40% of the country has no access to basic health
225,000 children believed to be in slavery –non-paid
40% of the country’s income from foreign aid
First reference to ‘narcoeconomy’
80% of graduates leave the country
Our Living Earth
Not uncommon for peoples of particular
geographical regions to hold ‘perspectives
of animism’ in their fascination with
spiritual powers associated with geological
events – earthquakes, volcanoes
Not common to North American First
Nations, Metis & Inuit. WHY?
Where might these beliefs exist in NA?
For our First Peoples - much more explicit
within beliefs associated with ‘weather’ Sila
Life ‘Alive’ In The Earth - Animism
Maori: It is in their hands we have our
being. Rūaumoko god of earthquakes
and volcanoes, Tāwhirimātea god of
wind and storm and Tangaroa god of the
Indonesian Proverb: As much as we have
certainty, we also have uncertainty. That
is our life.
Three Levels of Activity At Work In Trying to
‘Make Sense’ of Earth Events
The relationship between theory, evidence, and reasoning:
THEORY Development - Resolution
Reasoning – Cognitive –
Evidence Collected –
Key Aspects of Grade 7 Cluster 4
Composition of the Earth
Formation of rocks – nonliving
matter- and soil –both living and
Changes to the Earth – mountains,
volcanoes, earthquakes, tsunamis;
how do we explain these changes?
Resources, Careers and technologies
associated with Earth science.
How do we explain these
changes? Key slos!
7-4-12 Describe evidence to support the
continental drift theory and explain why
this theory was not generally accepted by
7-4-13 Describe evidence to support the
theory of plate tectonics, the role
technology has played in the development
of this theory and reasons why it is
generally accepted by scientists
To the ancient Greeks citizens, volcanoes' capricious
power could only be explained as acts of the gods –
often associated with anger toward human behavior
Ancient Greek philosophers proposed many theories
to account for the from and origin of the Earth and
events including volcanoes and earthquakes.
Made attempts to explain natural events removed
from a spiritual cause – albeit without understanding
the Earth’s composition – the advent of
For example, Aristotle, speculated that earthquakes
resulted from winds within the Earth caused by the
Earth's own heat and heat from the sun. Volcanoes,
he thought, marked the points at which these winds
finally escaped from inside the Earth into the
Tectonic Plates, Yes – but
Continental Drift? Hmmm
Two Traditions in Confrontation:
Mobilists & Fixists
The Early Mobilists….
The Franco-Italian Antonio SniderPellegrini, by 1858 in his volume La
création et ses mystères dévoilés had
provided a basis for accepting the notion
that the Atlantic Ocean had opened up as
a consequence of continental separation
The fit of these continental coastlines, first
enunciated by Francis Bacon in the 17th
century as “cuspidal to the south”, was
likely well-recognised in Europe
Setting the Stage...
A. Wegener (ca. 1926)
7-4-12 Describe evidence
used to support the continental
drift theory, and explain why
this theory was not generally
accepted by scientists.
Alfred L. Wegener – the “Outsider”
Alfred Wegener proposes continental drift (ca. 1912)
1: Earth is divided into both continents
Alfred Wegener, ca. 1920.
2: The distribution of fossil animals and plants re-enforces the
connection-points among the continents
Evidence from Past Climates….
In the modern world
glaciers are found near the
north and south poles.
Deserts are largely found in
bands that are parallel to
Extensive coral reef
complexes lie along the
Desert deposits and reefs that
are several hundred million
years old are found in bands
that suggest the equator was
oriented as shown on the left.
If we assume that the poles
and equator are fixed, the
continents must have been
in different positions as
shown on the left.
Put it all together, and see
that the continents were
once connected but have
drifted apart by ‘sliding’ over
or ‘plowing’ through the ocean floor
Driving Force?: Mystery, or
centrifugal force, or both?
“This is just stupid..!!”
• A lack of credibility – a climatologist not a
• Lack of evidence to support theory
• Theory not supported nor communicated with an
• What was suggested was not clear to his
audience - unconvinced
• A society that was closed to a ‘mobilist’ model
“This is just stupid..!!” Sir Harold Jeffreys of Cambridge University,
world’s leading geophysicist, declares that “this is geology’s darkest
Geology versus Mathematical Physics
Any force strong enough to ‘push’ a continent over a bed of
ocean floor would internally deform the continent instead
Not all pieces of the continental puzzle really match
Many continental margins don’t even fit well geometrically…
Even if they fit, so what! Lots of ‘fits’ are possible just by chance!!
Still to Come…
7-4-13 Describe evidence used to
support the theory of plate
tectonics, the role technology has
played in the development of this
theory, and reasons why it is
generally accepted by scientists.
By Next Wednesday
We need to see your lessons in
draft. They need to be handed in by
Wednesday for feedback.
We are available Tuesday &
Wednesday. We will try to give you
immediate feedback in person.