7th Grade Curriculum Earth History

1. EARTH HISTORY
Review
Created by Beverley Sutton
Pueblo Gardens PreK-8

2. Our Changing Earth
• Earth is a geologically active
planet.
• Huge quantities of energy
are always acting on the
surface of the Earth and its
interior.
• Observable evidence in the
present gives information
about processes and events
that occurred in the past.

3. How Scientists work:
Observation
• Using one or more of the five senses

4. How Scientists work:
Inference
• Based on what you already know about
footprints and the footprints you see …
What
happened
here?

5. Layers of the Earth

6. Let’s take them apart …
… and look at them one by one

7. Crust
• The outermost “skin” of Earth. Two types:
Oceanic crust (thinner, mostly basalt) and
Continental crust (thicker, mostly granite)

8. Lithosphere
• The crust and the uppermost part of the
mantle – brittle and cool

9. Lithosphere
• Like the skin and a little of the white of an
apple

10. Mantle
• Molten rock – between the crust and the
core

11. Core
• Center of the Earth: Made up of mostly
iron and some nickel.
• Outer core (liquid)
• Inner Core (solid)

12. Mineral
• a crystalline
inorganic solid
that occurs
naturally in the
Earth’s crust.

13. PHYSICAL properties of minerals

14. Rock
• inorganic solid that occurs naturally in
the Earth’s crust.

15. Rock Cycle –
a process that constantly recycles rock

16. Rock Cycle

17. Erosion
• The wearing away of rocks by weather
(wind, water), or chemical means

18. Sediments
• small particles of sand, dirt, broken up
rocks

19. Sedimentary Rock
• Formed by compaction and cementation.
Sediments are compacted (packed down) and glued
together (cemented). Grains are in layers sandwiched
between a muddy matrix
Limestone
Sandstone
Coal
Shale

20. Metamorphic Rocks
• Rock that was once one type of rock but has
changed to another under the influence of heat
and pressure. Grains arranged in bands.
Marble –
which was once limestone
Slate –
which was once shale
Quartzite –
which was once sandstone

21. Igneous Rock
• rocks that form
from magma
(melted, liquid Pumice
rock) that cools
and
crystallizes.
The crystals are
randomly arranged Granite
and interlocking.
Gabbro

22. Tectonic Plates
• Solid plates of lithosphere that float on
the mantle

23. Convection
• Convection -- Heat transfer in a gas or
liquid by the circulation of currents from
one region to another.

24. Divergent Boundary
• At divergent boundaries new crust is
created as plates pull away from each
other.

25. Convergent Boundaries
• Here crust is destroyed and recycled back
into the interior of the Earth as one plate
dives under another.
These are known as Subduction Zones -
mountains and volcanoes are often found
where plates converge.

26. Oceanic-Continental Convergence

27. Oceanic-Oceanic Convergence

28. Continental-Continental
Convergence

29. Transform-Fault Boundaries
• Transform-Fault
Boundaries are where two
plates are sliding past one
another.
These are also known as
transform boundaries or
more commonly as faults.

30. Fault
• a crack in the earth's crust resulting from
the displacement of one side with respect
to the other
Normal Fault
Strike-slip Fault

31. Law of Superposition
• In a sequence of
layered rocks, a given
bed must be older
than any bed on top
of it.
In other words, each
layer is younger than
those underneath it.

33. Law of Original Horizontality
• Most sediments, when originally
formed, were laid down horizontally.
In other words, most sediments settle in
flat horizontal layers.
If the layers are no longer horizontal
then something
happened to move
them.

34. How
landforms
change

35. Seismologist
• scientist who studies earthquakes

36. Seismograph
• an instrument that records the magnitude
(size) and duration (how long it lasted) of
an earthquake.

37. Richter scale
• the logarithmic scale used to measure
earthquakes.

38. Epicenter
• The point of the earth's surface directly
above the focus of an earthquake

39. Rock Column
• A diagram that
shows the
sequence of
rocks in a
particular area.
• Stratigraphy –
the science of
layered rocks.

41. Index fossil
• The fossil remains of an organism that
lived in a particular geologic age, used to
identify or date the rock or rock layer in
which it is found. Also called guide fossil.

42. Our Changing Earth
• Earth is a geologically active
planet.
• Huge quantities of energy
are always acting on the
surface of the Earth and its
interior.
• Observable evidence in the
present gives information
about processes and events
that occurred in the past.

43. Serene, still, and peaceful?
Wrong! A dynamic, always
changing world!