Review for 8th Grade Benchmark

I tried to link each fact to more information in case you didn't understand - STUDY HARD!  This test is difficult!

The best method to correlating rock layers is through index fossils. 
If we find fossils from oceanic animals in a desert area, we can assume that the area was once covered with water.
Fossils of tropical animals have been found in Antartica because Antartica used to be closer to the equator (think Pangea).
Mammals increased in number and humans developed in the Cenozoic Era.
Since tectonic plates are always moving around, the shape, location and placement of Earth's continents change over time (see Pangea link).
Earthquakes are caused by the movement of the plates - they displace and break rocks at the fault lines and the Earthquake is the shaking that radiates out fromt he breaking of the rock.
The lithosphere is composed of the Earth's upper mantle and crust.
The liquid layer of the Earth is the outer core - the inner core is pressed so tightly together that it is more like a solid.
The crust of the Earth is broken into plates - these plates are constantly moving.

 

Plate boundaries (more information here)

• Divergent boundaries -- where new crust is generated as the plates pull away from each other.
• Convergent boundaries -- where crust is destroyed as one plate dives under another.
• Transform boundaries -- where crust is neither produced nor destroyed as the plates slide horizontally past each other.
• Plate boundary zones -- broad belts in which boundaries are not well defined and the effects of plate interaction are unclear.

Convection currents are the circular motion in a liquid caused by heating and cooling.

Pangea
Seafloor spreading - great animation here too!
Cooling rates influence the texture if the igneous rock:

• Quick cooling = fine grains
• Slow cooling = coarse grains

Granite formation
Sandstone formation
Gneiss formation
Basalt formation
Conglomerate rock
Earth's spinning core creates Earth's magnetic field.

8th Grade Multiple Choice Study Guide for MONDAY'S BENCHMARK

• Brachiopods and coral fossils are ocean creatures.
• Fossils show evidence about the history of rocks and climate of an area.
• The principle of uniformitarianism is the principle that the answers to the past can be found in the present, meaning that everything is uniform in how it works. Such as a volcano erupting today would be the same as it would have been a billion years ago. Or rain would fall the same was today as it would in the time of the dinosaurs.
• Fossils most often form in sedimentary rock.
• The Earth is 4.5 billion years old.
• Uplifting forces can raise or elevate layers of the Earth.
• Earth’s features are constantly being built up AND worn down.
• The Grand Canyon is a result of erosion due mainly to water.
• Steep cliffs that remain were probably more resistant to erosion than surrounding rocks.
• Sandstone layers were likely formed from wind blown sand.
• The principle of superposition states that in a sequence of undisturbed sedimentary layers or lava flows, the oldest layers are at the bottom.
• Geologists study rocks.
• Rock layers were formed from layers of sediments that are deposited and transformed into rock over millions of years.
• Weathering breaks down rocks.
• Erosion transports rock pieces.
• Gravity produces avalanches and landslides.
• Physical weathering – caused by natural forces such as water freezing and thawing inside rocks
• Mechanical weathering – same as physical weathering
• Chemical weathering – happens when chemical reactions dissolve minerals.
• Variation of steepness in hill slopes is probably due to the softness and hardness of rock layers.
• Soil is formed over time – rock weathers, plants add organic materials and rain spreads minerals through the layers.
• Soil is a mixture of weathered rock, water, decayed organic matter, oxygen and mineral fragments.
• The top layer of soil contains the most organic matter.

7th Grade Open Ended Notes for FRIDAY'S BENCHMARK

Earth’s gravity pull is directly dependent upon the masses of the two objects only (the distance between the objects and the center of the Earth remains the same)

If the two objects have the same size but one has more mass than the other, then the more massive one is pulled more strongly by Earth’s gravity.

One object can have MORE mass than another – but they can both have the SAME volume.

The gravity of the Sun keeps planets in their orbits.  The Earth orbits the Sun because of the pull of the Sun’s gravity.

The lighter object orbits the heavier one, and the Sun is the heaviest object in the Solar System.

Earth and other planets orbit the Sun because the Sun is much bigger than the Earth and the other planets.

Earth and other planets orbit the Sun because they are less massive than the Sun.

8th Grade Open Ended Notes for FRIDAY's BENCHMARK

History is divided into 3 or 4 major segments of time or eras.

On any timeline, each “era” is labeled and the time is given for each.

Every timeline shows a sequence of major events for each era.

Every timeline uses a scale (example:  1 mm = 1 million years or 10cm = 1 year)

Every timeline has a beginning and an end.

The geological time scale covers billions of years – other timelines are much shorter.

The geological time scale shows more complex and extensive history  - including extinctions and major events.

The geological time scale shows human history as well – so most time scales can be considered part of the geological time scale.

Millions of years of Earth’s history are exposed in the Grand Canyon.

Rock layers and their relationships are easily seen.

Earth processes can be seen and inferred (weathering, erosion, deposition)

Landforms provide evidence for differential erosion.

Rock types can be observed.

8th Grade Open Ended Notes for Benchmark #1

The roots of grass can help preserve soil by keeping it in place - slowing the rate of erosion. 
Soil can be eroded by rain, run off (gravity) or wind.
Soil that is not covered by grass or other plants has a higher rate of erosion, which will cause it to lose more minerals and make growing plants harder.
Soil that is eroding quickly can become unstable - causing small or severe problems such as inability to grow plants or landslides.

Rock cycle:
Rocks are weathered (broken down), eroded (transported) and the pieces are deposited in other areas. 
The deposition causes rocks to form in other areas.
Erosion caused by water created the Grand Canyon.

7th Grade Open Ended Review for Benchmark 1

The Earth’s orbit is close to circular (only slightly oval or elliptical) so that the Earth is no significantly farther away from or closer to the Sun at any time during its orbit.

It is the tilt of the Earth on its axis that causes seasons.

Because the USA is facing away from the Sun in December, the Sun’s position in the sky is lower.

When the Sun in the sky is lower, the angle of incidence of sunlight is smaller spreading out the energy in a given area (more spread = less energy given to each spot).

Also the long nights and short days prevent us from warming up.

The higher the Sun is in the sky, the shorter the length of the shadows.  The lower the Sun is in the sky, the longer the shadow.

The Sun’s angle changes because the Earth is tilted on its axis.  As the Earth revolves around the Sun the Northern hemisphere is tilted towards the Sun in summer and away from the Sun in winter.

When the Northern hemisphere is tilted towards the Sun (in summer), the angle of the Sun is greater – causing shorter shadows.

When the Northern hemisphere is tilted away from the Sun (in Winter), the angle of the Sun is lower – causing longer shadows.

These websites will give you additional info if you get confused:
INTERACTIVE_WEBSITE:  https://owa.elizabeth.k12.nj.us/owa/redir.aspx?C=5af2621548fe4701af09db741cab3bf3&URL=http://www.livephysics.com/simulations/astronomy/sun-shadow-changes-with-seasons.html

EXPLANATION:  http://www.seaford.k12.de.us/es/vgray/planetary%20systems/Activity%2010%20Shadows%20and%20Seasons%20SG.doc

ACTIVITY:  https://owa.elizabeth.k12.nj.us/owa/redir.aspx?C=5af2621548fe4701af09db741cab3bf3&URL=http://www.exploratorium.edu/ancientobs/chaco/HTML/TG-shadows.html

ACTIVITY & WORKSHEETS:  https://owa.elizabeth.k12.nj.us/owa/redir.aspx?C=5af2621548fe4701af09db741cab3bf3&URL=http://webs.wichita.edu/lapo/seasons.pdf

Review for 7th Grade Benchmark #1: Open Ended questions

• The Earth's orbit is close to circular; therefore the Earth is not significantly closer to or farther from the Sun at any time.
• The tilt of the Earth causes us to have seasons.
• Because the US is facing away from the Sun in December, the Sun's position in the sky is lower.
• When the Sun in the sky is lower (winter), the angle of incidence of sunglight is smaller - spreading out the energy over a larger area.  Also, long days and short nights prevent the Earth from warming up in the winter.
• The higher the Sun in the sky, the shorter the length of the shadow.  The lower the Sun in the sky, the longer the length of the shadow.
• The Sun's angle changes because the Earth is tilted on its axis.  As the Earth revolves around the Sun the northern hemisphere is tilted toward the Sun in the summer, and in the winter is tilted away from the Sun.
• When the northern hemisphere is tilted towards the Sun (summer), the angle of the Sun is greater.
• When the northern hemisphere is tilted away from the Sun (winter), the angle of the Sun is smaller.