Do you ever wonder about the different rock formations and mountains on the Earth? Why do some rocks form like they do and what makes them look so different? Rocks and other materials on Earth’s surface are
constantly being broken down both chemically and physically. The products of
weathering include clay, sand, rock fragments, and soluble substances. What is the difference between weatheringand erosion?
Weathering
Weathering is the process of decomposing, breaking up, or changing the color of rocks. Chemical weathering involves chemical changes in the minerals in the rock or on the rock's surface that will make the rock change its shape or color. Carbon dioxide, oxygen, water, and acids all may cause chemical weathering.
Mechanical weathering involves the process of breaking down a rock into smaller pieces, but not changing the minerals in the rock. Mechanical weathering may be caused by ice, frost, plant roots, running water, or heat from the sun.
Once the small pieces of rocks are changed, or broken apart by weathering, they may start to be moved by water, wind, or ice. When the smaller rock pieces, which are now pebbles or sand start to move away by these natural forces, we call this erosion.
If a rock is broken or changed, but stays where it is, it is called weathering.
If the pieces of weathered rock move or are washed away, it is called erosion.
The Rock Cycle is a group of changes among rocks. There are three types of rocks found on the Earth.
Igneous
Igneous rock is formed when molten (hot,melted) rock forms into solid rock. Examples of Igneous rock are granite, obsidian, and basalt. See pictures below:
Metamorphic
Metamorphic rocks are formed from high temperatures and extreme pressures. Metamorphic rocks make up a large portion of the Earth's crust. Here are two examples of Metamorphic rocks. The first once is pronounced like "nice" and the second one is marble.
Sedimentary
Sedimentary rocks are formed when layers of sand, and sediment (small bits of rock) are layered upon each other on the land and within bodies of water on the Earth. Sandstone and shale are two examples of Sedimentary rocks.
Watch this Prezi to learn more about how the different types of rocks form the rock cycle. After watching the Prezi, see instructions for foldable.
There are three types of plate tectonic boundaries and these all change the Earth's surface, as well as the ocean floor. Each type of plate boundary moves in a different way. On this post, we'll explore the three types of plate boundaries, how they move, and what happens as a result of their movement.
Divergent Boundary
The first kind of boundary we will look at is called a Divergent Boundary. If you look closely at the word, "Divergent", you can almost see the part of the word, "Different" in it. If you can remember that, it is helpful in remembering how these plates move. Because Divergent plates are like "different", I like to think that they don't get along because they are different and therefore they move apart. And that is exactly what Divergent boundaries do! Another word that might be helpful to trigger your memory is "Divide". As the plates are forced apart melted rock comes to the surface and hardens into new crust. The area between the two plates where the melted rock comes to the surface is called a rift valley. A large chain of volcanic mountains can form along the rift as the melted rock rises and cools into new rock.
Check out this short animation to see a divergent boundary.
Convergent Boundary
Another type of boundary is when plates come together or collide with each other. One plate is forced down and melted while the other is forced upward and folded into mountains. A trench is formed where the two plates meet. This is called a "Convergent Boundary".
This is a real-world example of a Convergent Boundary. See how the land in the middle of the picture is pushing up where the two sides meet? Pretty amazing!
Transform Boundary
The last type of boundary we'll look at is called "Transform"or"Sliding"boundary. The reason it is called this is because instead of the plates moving away from each other, or crashing into each other, the plates are sliding by each other, kind of like when you pass someone in the hallway. These plates slide along beside of each other. Since plate boundaries are not smooth, plates do not slide smoothly. The plates can suddenly break free of each other and cause powerful earthquakes. One of the most well known Transform Boundaries in the world is called "The San Andreas Fault", which is located in the state of California. California experiences many earthquakes each year because of this boundary, or fault zone. Notice the red arrows in this map of the San Andreas fault, which show the two land masses sliding beside each other.
Plate tectonics is fascinating to study. Check out this site for more information to understanding about plate tectonics. Geography4Kids
You have always heard that the Earth is moving, right? Well, not only is it rotating every 24 hours and revolving around the Sun once every 365 (and 1/4) days, the land is also moving! There are large masses of land called plates that move around constantly because of the Earth's thermal (heat) energy.
These plates are kind of like the "skin" on the planet. Now, when you think about these plates moving, don't get too excited. They are not moving too much. In fact, these plates only move about a few centimeters a year.
It is not a lot, but sometimes it doesn't take much movement to cause a lot of trouble for lots of people. The places where these plates touch is not exactly the same as the continents that we all know about. Here is a picture of the "plates" around the planet. The plates are the outlines in red.
Depending on where the boundaries are (where they touch) kind of decides what movement happens when these plates are sliding around. Many times we are not aware of these movements, but many of these "small" movements can cause earthquakes. Most earthquakes are very minor, but sometimes they can be very devastating, causing lots of destruction, as seen in the pictures below.
An earthquake in Cuba causes major damage to a highway.
Major structure damage is caused by an earthquake in Kobe, Japan.
There is an area where one of the plates appears to be touching several different areas at the same time. This is called "The Ring of Fire", and is the area where many earthquakes and volcanic eruptions happen on our planet. You can see all the different land masses that are affected around the world by this "Ring of Fire." This area is in constant motion and activity.
Enjoy this short video by Bill Nye, where he explains a little about Plate Tectonics.
Have you ever wondered what is deep inside of the Earth? As a child, did you ever think you could dig a hole all the way to the other side of the planet? Well, don't wonder any more because you will never be able to do that. The Earth is way too big and thick and you probably would not even get through the first layer. Watch the presentation below to get an idea of the four layers of the Earth.
The first layer of the Earth is called the Crust and it is the smallest part, only about 5 to 6 miles thick. The Earth's crust is the most common place for earthquakes to occur.
The next layer is called the Mantle. The Mantle is the thickest layer of the inside of the earth, making up almost 75 percent of the volume of the Earth! The Mantle is like an underground ocean of liquid rock. In fact, lava that comes from volcanoes comes from the Mantle.
The next layer is called the Outer Core. The Outer Core is also a hot liquid and it surrounds the final part, the Inner Core. The Outer Core is responsible for protecting the Earth's magnetic field.
The final part of the Earth's layers is the Inner Core, which is a solid ball, made of primarily nickel and iron. Scientists believe that the Inner Core's temperature is about 5000 degrees Celsius! That is pretty hot!
"Earth poster" by Kelvinsong - Own work. Licensed under CC BY-SA 3.0 via Commons - https://commons.wikimedia.org/wiki/File:Earth_poster.svg#/media/File:Earth_poster.svg
Just what are fossils and why are they so important? You might think that a fossil is just an animal or a plant that died inside a rock, but fossils are so much more! While it is true that fossils are the remains of animals and plants, we can learn so much from fossils. For instance, many fossils contain evidence of plants and animals that no longer exist on the Earth. Also, depending on what layer they are found in, we can make a hypothesis about why these animals and plants are no longer here. The kinds of fossils found in rocks are different because life on Earth has changed over time. Fossils are formed when an organism (a living thing) dies and the empty spaces in that organism fill with mineral-rich groundwater. This process takes many, many years.
Basically there are 2 types of fossils that exist, Body Fossils and Trace Fossils. Body Fossils include parts and remains of animals that were once alive. These are usually only the hard parts of animals, such as bones, teeth, and shells. Trace Fossils are more like footprints, trails, or imprints of animals rather than actual evidence of the animal or plant itself. The word fossil comes from the Latin word "fossilis", which means "dug up". Fossils are made over time after an organism dies and is usually buried by a natural process, such as sinking into the mud. Over time, more and more sediment covers the remains and it becomes pressed down, or impacted. After a long time, the remains are no longer made up of the same materials, but undergo a change and are more like rock.
This is an example of a Trace Fossil. You can see the footprints of a creature from long ago!
This is an example of a Body Fossil, where you can actually see the fossilized remains of an organism.
For more interesting information about fossils, please visit the site called:
The Earth's layers tell a story about the events that have happened in the Earth's history and can give scientists important clues about when these events happened. Scientists look at the different layers of the Earth, which build up over time, millions and billions of years, in fact. You may have seen these layers yourself when riding in the car on a trip! These layers can be seen all around you, and are also more prominent in different areas of the planet. Check out these pictures of layers of rocks: All of these pictures are of layers of rock in the state of Virginia.
This is a cut-away near the Radford area of Virginia.
This is an example of different types of layering of rocks. This was taken in northern Virginia.
Again, you can see the different layers of rock alongside this road, located in the Valley and Ridge region of Virginia. Deep inside these layers of rock are many stories about the Earth's history.
Scientists use a method called radiometric dating, where they analyze a sample from the Earth's crust and study it to figure out the age of each layer of rock. Within these layers scientists discover many things. They find different types of rocks and the rocks form many patterns; sometimes straight across, but sometimes the pattern zig zags, indicating perhaps an earthquake. Many forms of life are found in these layers of rock as well. Scientists discover fossils of all types of plants and animal life. It is amazing the stories that can be told from studying the layers of rocks around our planet.
Please take a minute to view this slide show that illustrates some of the amazing views of Earth and her amazing "rock" story.
