The Rock Cycle

The Rock Cycle
 Interactive         Video      The Rock Cycle in Action      Song

The Rock Cycle Never STOPS!
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Types of Rocks

Rocks are not all the same!

The three main types, or classes, of rock are sedimentary, metamorphic, andigneous and the differences among them have to do with how they are formed.

Sedimentary
Sedimentary rocks are formed from particles of sand, shells, pebbles, and other fragments of material. Together, all these particles are called sediment. Gradually, the sediment accumulates in layers and over a long period of time hardens into rock. Generally, sedimentary rock is fairly soft and may break apart or crumble easily. You can often see sand, pebbles, or stones in the rock, and it is usually the only type that contains fossils.

Examples of this rock type include conglomerate and limestone.

Metamorphic
Metamorphic rocks are formed under the surface of the earth from the metamorphosis (change) that occurs due to intense heat and pressure (squeezing). The rocks that result from these processes often have ribbon like layers and may have shiny crystals, formed by minerals growing slowly over time, on their surface.

Examples of this rock type include gneiss and marble.

Igneous
Igneous rocks are formed when magma (molten rock deep within the earth) cools and hardens. Sometimes the magma cools inside the earth, and other times it erupts onto the surface from volcanoes (in this case, it is called lava). When lava cools very quickly, no crystals form and the rock looks shiny and glass like. Sometimes gas bubbles are trapped in the rock during the cooling process, leaving tiny holes and spaces in the rock.

Examples of this rock type include basalt and obsidian.

Earth's Rock cycle in Action

When Earth's tectonic plates move around, they produce heat. When they collide, they build mountains and metamorphose (met-ah-MORE-foes) the rock.

The rock cycle continues. 

Mountains made of metamorphic rocks can be broken up and washed away by streams. New sediments from these mountains can make new sedimentary rock.

The rock cycle never stops. More Info

Thank you

The Earth's Layers Lesson

The Earth's Layers   video

Interactive Earth

The Four Layers

The Earth is composed of four different layers. Many geologists believe that as the Earth cooled the heavier, denser materials sank to the center and the lighter materials rose to the top. Because of this, the crust is made of the lightest materials (rock- basalts and granites) and the core consists of heavy metals (nickel and iron).

The crust is the layer that you live on, and it is the most widely studied and understood. 

The mantle is much hotter and has the ability to flow. 

The Outer and Inner Cores are hotter still with pressures so great that you would be squeezed into a ball smaller than a marble if you were able to go to the center of the Earth!!!!!!

 

The Crust

The Earth's Crust is like the skin of an apple. It is very thin in comparison to the other three layers. The crust is only about 3-5 miles (8 kilometers) thick under the oceans(oceanic crust) and about 25 miles (32 kilometers) thick under the continents (continental crust). The temperatures of the crust vary from air temperature on top to about 1600 degrees Fahrenheit (870 degrees Celcius) in the deepest parts of the crust. You can bake a loaf of bread in your oven at 350 degrees Fahrenheit , at 1600 degrees F. rocks begin to melt.

 The crust of the Earth is broken into many pieces called plates. The plates "float" on the soft, plastic mantle which is located below the crust. These plates usually move along smoothly but sometimes they stick and build up pressure. The pressure builds and the rock bends until it snaps. When this occurs an Earthquake is the result!

Notice how thin the crust of the Earth is in comparison to the other layers. The seven continents and ocean plates basically float across the mantle which is composed of much hotter and denser material.

 

The crust is composed of two basic rock types granite and basalt. The continental crust is composed mostly of granite. The oceanic crust consists of a volcanic lava rock called basalt.

Basaltic rocks of the ocean plates are much denser and heavier than the granitic rock of the continental plates. 

Because of this the continents ride on the denser oceanic plates. The crust and the upper layer of the mantle together make up a zone of rigid, brittle rock called the Lithosphere. 

The layer below the rigid lithosphere is a zone of asphalt-like consistancy called the Asthenosphere. The asthenosphere is the part of the mantle that flows and moves the plates of the Earth.
 

The Mantle

The mantle is the layer located directly under the sima. It is the largest layer of the Earth, 1800 miles thick. The mantle is composed of very hot, dense rock. This layer of rock even flows like asphalt under a heavy weight. This flow is due to great temperature differences from the bottom to the top of the mantle. The movement of the mantle is the reason that the plates of the Earth move! The temperature of the mantle varies from 1600 degrees Fahrenheit at the top to about 4000 degrees Fahrenheit near the bottom!

 

Convection Currents

The mantle is made of much denser, thicker material, because of this the plates "float" on it like oil floats on water.

Many geologists believe that the mantle "flows" because of convection currents. Convection currents are caused by the very hot material at the deepest part of the mantle rising, then cooling, sinking again and then heating, rising and repeating the cycle over and over. The next time you heat anything like soup or pudding in a pan you can watch the convection currents move in the liquid. When the convection currents flow in the mantle they also move the crust. The crust gets a free ride with these currents. A conveyor belt in a factory moves boxes like the convection currents in the mantle moves the plates of the Earth.

Outer Core 

The core of the Earth is like a ball of very hot metals. (4000 degrees F. to 9000 degrees F.) The outer core is so hot that the metals in it are all in the liquid state. The outer core is located about 1800 miles beneath the crust and is about 1400 miles thick. The outer core is composed of the melted metals nickel and iron.

Inner Core

The inner core of the Earth has temperatures and pressures so great that the metals are squeezed together and are not able to move about like a liquid, but are forced to vibrate in place as a solid. The inner core begins about 4000 miles beneath the crust and is about 800 miles thick. The temperatures may reach 9000 dgrees F. and the pressures are 45,000,000 pounds per square inch. This is 3,000,000 times the air pressure on you at sea level!!!

 

Answer the following questions on a sheet of paper with your partner.

1. Name the four layers of the Earth in order from the outside to the center of the Earth.

2. What causes the mantle to "flow"?

3. What are the two main metals that make up the outer and inner core?

4. Describe in your own words how the Earth's layers were formed. 

Thank you...
http://volcano.oregonstate.edu/earths-layers-lesson-1

Everything You Need to Know About Planet Earth 

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Gravity and the Solar System

Gravity and the Solar System
Links Brain Pop Videos: Solar System   Gravity  
Because of gravity, if you drop something, it falls down, instead of up. Well, everybody knows that! But, what does this really mean? What is gravity?

Gravity has played a big part in making the universe the way it is. Gravity is what makes pieces of matter clump together into planets, moons, and stars. Gravity is what makes the planets orbit the stars--like Earth orbits our star, the Sun. Gravity is what makes the stars clump together in huge, swirling galaxies.

A great scientist, Albert Einstein, who lived in the 20th century, had a new idea about gravity. He thought that gravity is what happens when space itself is curved or warped around a mass, such as a star or a planet. Thus, a star or planet would cause kind of a dip in space so that any other object that came too near would tend to fall into the dip. This 2-D animation gives an idea of how gravity works in 3-D.

 
Fun facts

• The gravity on the moon is about 16 percent of that on Earth, Mars has about 38 percent of Earth's pull, while the biggest planet in the solar system, Jupiter, has 2.5 times the gravity of Earth.
• Though nobody "discovered" gravity, legend has it that famous astronomer Galileo Galilei did some of the earliest experiments with gravity, dropping balls off the Tower of Pisa to see how fast they fell.