Our Dynamic Earth Review Video

We've been working hard as we've learned about the Earth. Check out the video below to see what we've been up to. It will also help you review for our test. Also, on the right (under important links) there is a study guide, online flash cards and a review game. Check them out!

Earth's Outermost Layer

The Earth has not always looked the same as it does today. Over the last 100 years, scientists have gathered much evidence to show that the Earth has changed.

In the early 1900's Alfred Wegener proposed that the continents were once joined together as a supercontinent named Pangaea. He had several pieces of evidence to help prove his theory...the same fossils can be found on different continents, mountain ranges line up when the continents are moved together, the shape of the continents match like puzzle pieces, and climate evidence suggests that Africa was once cold enough to have glaciers and Antactica was warm enough for tropical plants. Unfortunately, Wegener could not explain HOW the continents moved, so his Theory of Continental Drift was not accepted.

In the 1950's, new technology allowed scientists to study the ocean floor. There, they discovered a huge mountain range called the Mid-Ocean ridge. This is the longest mountain range in the world. Upon further investigation, scientists realized that magma was squeezing through an opening in the ridge and was pushing older rock to the sides. As rock gets pushed to the side, continents also get pushed along. This process is referred to seafloor spreading and it helps explain Wegener's theory.

Today, scientists use the Theory of Plate Tectonics to explain how the continents have moved. This theory states that the lithosphere is broken into several pieces, called tectonic plates. These plates float on the asthenosphere and are in constant motion. Scientists believe that convection currents in the mantle, as well as slab pull, cause the plates to move. There are 3 different types of plate boundaries...convergent (coming together), divergent (moving apart), and transform (sliding past each other).

California is very tectonically active. Down in Southern California, the San Andreas Fault separates the North American Plate from the Pacific Plate. Movement along this transform plate boundary creates earthquakes. In northern California, subduction of the Gorda and Juan de Fuca Plates is responsible for Mt. Shasta and other Cascade Range volcanoes.

The Earth's surface has changed alot over the past 4.6 billion years. Even though the plates are only moving a few centimeters per year, they will continue to change the face of our planet.

Snack Tectonics

Earth Model Update

Last week we started working on our Earth models. Right now, the focus is on the interior layers. The students calculated how thick each layer should be so our models will be to scale. Next, they marked the layers on the ball then painted. All the models are off to a great start! Thank you to everyone who made a donation to help support this project!

The Earth's Interior

Over the past few days, we've been focusing on the interior of the Earth. We learned that scientists use seismic waves to determine that there are layers. When the waves pass through a layer that has different properties, the waves bend. We also learned about the 4 main layers of the Earth...the crust, mantle, outer core and inner core. They all have very different properties. Refer to your notes if you can't remember how they're different from each other. In addition, we learned about 2 very special layers: the lithosphere and the asthenosphere. The CRUST AND THE UPPERMOST MANTLE make up the brittle outer layer called the lithosphere. This layer is broken into large pieces called plates. We'll be learning more about these in the weeks to come. The asthenosphere is a thin layer directly below the lithosphere. This layer is slightly melted and acts kind-of like silly-putty...moving very,very slowly.

We also learned that there are convection currents in the asthenosphere and in the outer core. The currents of the outer core create Earth's magnetic field.

Have anything you want to share about the interior of the Earth? Did you find anything to be particularly interesting?

Our Dynamic Earth!

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Making Observations

This week we started learning about some skills that scientists use. Being able to record accurate observations is one of these skills. Scientists need to record both qualitative and quantitative observations. Below are some photos showing students as they practice making observations.

7 Habits of Highly Effective Teens

Last week we were focusing on skills that would help us be successful middle schoolers...in science, on the playground, in PE, language arts, and every other aspect of school. The skills you learned will also be beneficial as a high schooler, college student, and adult. I know that several of you have already tried using a few of these skills and indicated that they have been helpful. It is my goal (begin with the end in mind!) to continue to re-visit these habits throughout the school year.

Did any of you hear something last week that really made you think about your life? Next time a difficult situation comes up, do you think you will handle it differently? Any thoughts about the 7 habits you'd like to share?

Don't let fear keep you from reaching your goals.

"You are the driver, not the passenger"

Today we talked about the importance of having a proactive attitude...taking responsiblity for your life and making things happen. We can only control how we respond to a situation, and cannot control what other people do. Listen to your language...are you being proactive, or reactive? Please share one time when you acted in a proactive manner. If you can't think of one, share a time when you were reactive...how could you have handled it differently?

This is an assignment. You must write your first name, last initial and period to receive credit. To get started, click on "comments" on the bottom right of this post.

Paradigms

We've been talking about the idea that we all see the world in different ways. There are times we view a situation different from the way our friend views the same situation. As a result, we sometimes find ourselves having a disagreement with our friends. If we could step back and look through our friends "glasses" we might be surprised how different things look.

Have you ever been in a situation where you had a shift in your paradigm (point of view)?

Welcome!

Welcome to Ms. DeGraff's science blog. I will be using this site to keep parents and students up-to-date. Check back frequently to see what we're studying, to participate in polls, to see class pictures, class video's and more.

This will be an interactive site where parents and students can leave comments. You do NOT need to set up an account to leave a comment. Follow the directions on the comment page to leave your remarks. But remember, all comments will be reviewed before they are posted. :-)

Again, welcome to 6th grade science! I'm looking forward to a fabulous year!