They move because of convection currents in the mantle of Earth. 

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To start class today, since most kids had never heard of the San Andreas Fault, I showed the trailer for the 2015 movie. The movie is about a 9.6 magnitude earthquake happening on the most well-known fault line in the United States. The movie is over-the-top dramatic, but it made the kids more aware of the potential catastrophe a large-scale earthquake could cause. The Earth has never experienced an earthquake with a magnitude greater than 9.5 in recorded history. The 9.5 magnitude earthquake occurred in Chile in 1960. Most scientists agree that a magnitude 10 earthquake is unlikely due to there not being a fault long enough to create one that large. So, when we talk about an earthquake above a magnitude of 8, it would be very destructive.

Speaking of destructive, we resumed yesterday's discussion about earthquakes with a recap of the Cascadia Subduction Zone. We live on an active fault line called the Cascadia Subduction Zone. It is the result of the Jan Del Fuca plate sliding under the North American plate. It is responsible for creating the Cascadia Mountain range. The plates are not smooth, so as the denser plate slides under the less dense plate, it pulls the less dense plate with it, and causes a bulge (the mountains). Eventually, the area that is being pulled down will break free and pop up, which could cause a massive earthquake and a resulting tsunami. This type of earthquake is called a megathrust. The last one in this area happened around 1700. For more information, there are several websites and articles. This one is a quick, no-nonsense website, the Pacific Northwest Seismic Network.

We prepare for the "what if" situations of earthquakes here at school by practicing earthquake drills. The kids "stop, drop, and cover" under their tables. To illustrate why this is done and how it works, I showed a video of a classroom in Alaska and what happened when an earthquake occurred. Drills do work!

 After long, really great discussions, we started investigating why the plates are moving, and what scientists know. Back when I was in elementary school, I learned about the concept of Continental Drift. A scientist called Alfred Wegener, way back in the 1920s, proposed the idea because he said the continents look like they once fit together like puzzle pieces. I remember being in a museum and hearing a talk about it. Initially, the concept was thought to be silly. The continents don't float on the ocean. But people agreed that it did look like a puzzle. As scientists started learning more about seismic activity, the idea of tectonic plates emerged, and eventually, the idea of tectonic plates moving came back. Without giving too much away, I had the kids do the Building Pangaea activity to learn what kind of evidence has been collected to help prove the theory.

The chapter page today was digital. The kids got it in Canvas and used a link in Canvas to get to Gizmos. All the kids in the district have an account with Gizmos. If they don't use the link, they will have a time limit for the activities.

First, the kids get to know the tools. They can move the continents and rotate them. They use the screenshot tool in the simulation to add to the digital chapter page. 

Next, they click on different pieces of evidence and try to get them to line up just right to show how the continents may have once been together.

We didn't have time to finish, so we will continue and submit on Monday. I will be out at a district meeting tomorrow, so Bill Nye will take over with a lesson about earthquakes.

 

 

Shallow earthquakes generally cause more damage and can be felt more.

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We started today with a video about how we know what the layers of the Earth are like. There are reviews of vocabulary we covered in earlier units, like density, refraction, and convection currents. 

After a review of yesterday's Earth's Crust & Earthquakes, where the kids discovered that the closer to the surface an earthquake occurs, the more damage is done, we discussed the difference between the numbers assigned to an earthquake's magnitude. Here is some information from the USGS:

It's hard to comprehend. I wish we had an earthquake simulation room where the kids could stop, drop, and cover and then feel the amount of shaking that happens at different magnitudes... 

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Next, the kids did a progress tracker in Canvas that covered the information in their notes about rocks, minerals, and the layers of the Earth. The results of this progress tracker were the best of all that we've done all year! That makes me very happy! My sixth graders are turning into efficient, problem-solving 7th graders!

We ended class with a presentation about earthquakes. This covered the causes (tectonic plate shifting, volcanoes, and other disturbances), where they occur (85% on the Ring of Fire, 15% on the Mediterranean-Himalayan Belt, and 5% at the Mid-Atlantic Ridge). Of course, they happen in other locations, but just a fraction of them.  Then, we compared magnitude and intensity. Magnitude is the amount of shaking, and intensity is the amount of damage done. The magnitude is a scientific measurement. The intensity is subjective. Like the EF Scale with tornadoes, if a high-magnitude earthquake happened in an area where no people were affected (the ocean floor, maybe?), it wouldn't get an intensity rating.

I asked each class if they knew of any areas prone to earthquakes in the United States. In the past few years, fewer and fewer kids have seen the movie San Andreas, which came out in 2015. So, fewer and fewer kids know about that fault line where some major seismic events have taken place. But most kids did say they thought California was prone to earthquakes. None of my classes mentioned the greater Seattle area as being earthquake-prone. But we are! We are on the Cascadia Subduction Zone. This is an area ripe for a large-scale earthquake. We'll talk more about it tomorrow and in the coming weeks. 

Some classes didn't get to the very end of the presentation, where we compared the times recent earthquakes have lasted. Most earthquakes last between 10 and 30 seconds. The 2011 earthquake in Japan lasted 5 minutes! We will start here for the classes that didn't finish the presentation.

 

Example:

Sedimentary rock gets smooshed with heat, becoming metamorphic.

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Yesterday, we were looking at minerals found all over the Earth, and today we pulled way back and compared the different types of Earth's crust. The kids read Layers of the Earth and looked for easily recognizable features that distinguish the layers of the Earth. Instead of complete sentences, they wrote some keywords on Earth's Crust & Earthquakes. Here is an example of the comparisons they made:

• Inner core: Solid, very hot
• Outer core: liquid, very hot
• Lower mantle: solid due to immense pressure
• Upper mantle: solid, but taffy-like, so it flows
• Continental crust: Cold, thicker, and less dense than oceanic crust because of less pressure (air instead of water)
• Oceanic crust: Cold, thinner, and denser than continental crust because of more pressure (water instead of air)

Part 1 of Earth's Crust & Earthquakes had the kids use their Chromebooks and follow directions in Canvas for how to use the Seismic Explorer. This tool allows you to see the earthquakes that have happened from 1980 until today. If you click "start," the earthquakes show up in order of appearance since 1980. 

Then, they used a cross-sectional tool to see the depths of the earthquakes in a 3-D model.

Part 2 had the kids find Ridgecrest, California (the earthquake we investigated in the first lesson of this unit), and determine the depth of that earthquake.

Part 3 was to analyze data from 10 earthquakes, with their magnitude and depth, and the number of fatalities, to determine the relationship of depth and magnitude to the amount of damage done.

At the end of class, I shared a website that students can use to explore earthquakes that are recorded every day. You can change the settings to look at earthquakes of specific magnitudes, and for the period of time they were recorded (in the last hour, day, week, or month). We noticed that there has been a lot of seismic activity in our area of the Pacific Northwest in the past month!

Metamorphic rocks can have bands and small crystals. They aren't as crumbly as sedimentary rock that also appears to have bands or layers. 

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The kids got to wear goggles today! It's always a fun day when you get to wear goggles. 

To better understand the way geologists and other scientists determine how to tell minerals apart from one another, we investigated the properties of minerals. Each group started with a material that had the potential to be used to make jewelry. Their job was to determine what the material was. They looked at the Properties of Different Minerals sheets and tested the material they received. 

On the Mineral Identification lab sheet, they looked at properties including color, transparency, luster, crystal shape, and hardness. They were trying to determine if the material was acrylic, glass, diamond, or fluorite. They could rule out acrylic and glass because those materials don't have a crystal shape. Both diamonds and fluorite have crystal shapes, but the sample given had an octahedron shape. The final test that was conclusive was the test for hardness. On the Mohs' hardness scale, a diamond is the hardest substance. Only a diamond can scratch a diamond. Fluorite is a 4 on the hardness scale. It can scratch copper, but not glass. The sample could not scratch glass. The sample that every group had was fluorite. (Do you think we would give 6th-graders real diamonds to test?)

The next lab is where the goggles came in. Each group was given a sample of a mineral. They were to determine if the sample was quartz or calcite. Calcite is softer (a 3 on the Mohs' hardness scale) than quartz (a 7 on the hardness scale). The other tests weren't definitive until the acid test. Calcite will react to acid by fizzing and bubbling. The kids donned their goggles and tried it out. All the samples were calcite, so each group got to see the reaction. 

Now that we have a better understanding of soil, rocks, and minerals, we can move back to the big picture, and big structure of tectonic plates!

It is a common misconception that diamonds are made of coal. Diamonds are a pure form of carbon, formed under very high temperatures and extreme pressure. Coal is carbon and other elements, and is created with much less heat and pressure than diamonds.

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After a busy week of SBA testing and lots of activities about rocks in science, we let Bill Nye take over. Yesterday, the kids tried classifying rocks into igneous, sedimentary, and metamorphic. We didn't talk a lot about the processes that get them to their different states within the rock cycle, but Bill Nye does a great job of filling in those gaps. The kids answered the questions on the Bill Nye - Rocks & Soil sheet as they watched the episode. 

Igneous rocks form when magma or lava cools.

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We started with a quick review of the rock cycle by watching a BrainPop episode. A big piece of the puzzle about how the Earth's surface changes was revealed. I paused the video in that spot. They're talking about the heat and characteristics of rock deep in the Earth. The animation showed rock moving in a circular pattern, and they explained that the hot rock rises to the surface. Remember when I said that the concept of convection currents would come back? Here it is! The heat from the Earth's core causes the molten rock to rise. The molten rock (magma) is in constant motion.

Today's lab had the kids investigating ways to identify whether a rock is igneous, metamorphic, or sedimentary. They used the Characteristics of Rocks sheet, which gave examples of some of the characteristics of the different rocks, to try to classify them. They recorded the clues that they thought they observed on the Identifying Rock Types lab sheet. The results are in this photo:

When each group was satisfied that they had properly identified the rocks, they were given the mystery rock. On the back of Identifying Rock Types, there is a story about some hikers who found an unusual rock. The kids were given a comparison chart to use to identify the mystery hiker's rock. They determined that the rock was garnet schist. Garnets are gemstones that are not rare, but usually very small. The samples we have contain several garnets. They mostly looked dull, brownish-red. If polished, they would look more like the garnet they use in jewelry. 

Garnet schist:

Garnet jewelry:

We ended class by looking at some common rocks found around the base of volcanoes. Most kids are familiar with obsidian (thanks, Minecraft), but don't realize it's fairly common. Another common rock around volcanoes is scoria. Scoria is similar to pumice. It is very light and has lots of little holes in it. Scoria is formed when lava that is runny and has lots of gas bubbles cools rapidly. Obsidian forms from really thick lava that doesn't have a lot of gas bubbles. I had several samples of each that I picked up off of a road in Kenya last summer. I was near a volcano, and the gravel roads contained both obsidian and scoria. My luggage was so heavy coming back! I know you aren't supposed to take stuff like that, but it was literally everywhere and used as gravel, so I didn't feel too bad. Please don't report me to the authorities. Unless they make me go back to replace it, because I'd love to go back!

 

Like water that can go up into the sky and deep into the ground in different states, rocks also change depending on where they are. They can be high at the top of a mountain or deep within the earth. They change shape and composition over long periods of time.

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To learn about the rock cycle, the kids played the Rock Cycle Game. This is a board game where the players make their way around the board and record what happens to their rocks. Sometimes the rock erodes and becomes sediment, which goes deep in the earth, and under pressure and heat, becomes a metamorphic rock. But some sedimentary rock breaks down again and turns back into sediment. Metamorphic rock can also become sediment by wearing down. But metamorphic rock might melt and turn into igneous rock. Igneous rock can fall apart to become sediment. This is the rock cycle. It isn't a cycle that goes in a definite order. A sedimentary rock does not have to become a metamorphic rock, and a metamorphic rock does not have to become an igneous rock. The point of the game was to show that there is no particular direction the rocks need to go. It all depends on circumstances.

After analyzing their data from the game, the kids answered questions on the Types of Rocks page with their groups. Then, we used the answers to create notes about rock types.

Instead of typical notes, we made a map of sorts to show how the rock cycle works on the Rock Cycle Model. We discussed bedrock and defined it as solid rock found everywhere on Earth, usually under sediments. What are sediments? Sediments are sand, soil, and rocks. Bedrock is made of sedimentary rock like the ones the kids learned about in yesterday's lab - limestone and sandstone. Then, we drew arrows and labeled the processes that take place for rocks to transform to become other types of rocks.

 

Mountains are made from different rocks and minerals depending on how they were formed and where they are located. They can look different because of their age as well. 

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We explored a bit today about what happens to rocks as they heat up. We watched a video about glassblowing. Glass is made of sand, and sand is made of rocks. So, as rocks heat up, they can melt!

Then, I showed a couple of videos that show what happens as you go deeper into the Earth. The first video shows how deep humans have been able to dig into the earth. It turns out that it isn't far at all related to the size of the Earth. When drills reach a certain point, they melt because the rock gets hotter the deeper you dig. We will learn more about how scientists know about the layers of the earth, their composition, and the temperature as we move through this unit.

Next, the kids went with their groups to the lab stations. There were two activities they did and recorded their observations on the Rock Investigations lab sheet. 

One investigation used clay to simulate rocks at different temperatures. The kids read about how rock behaves at different temperatures, then used warm clay, room-temperature clay, and cold clay to simulate rocks at different depths in the Earth. They placed the clay between two heavy bricks and let gravity do its thing. 

For the other investigation, the kids had samples of four different rocks: sandstone, limestone, granite, and basalt. They made observations with hand lenses and by rubbing the rocks together. They observed that the sandstone and limestone (sedimentary rocks) felt gritty, and when they rubbed them together, it created dust on the counters. With hand lenses, they could see sand compressed in layers, or fossils. The basalt and granite are igneous rocks. When looked at with hand lenses, the kids observed crystals and bands. They didn't produce dust when rubbed together.

We will go over this investigation tomorrow and discuss the findings.

 

Mount Everest was formed differently. A preview of things to come: Mount Everest was formed when two continental plates collided. Mount St. Helens was formed when an oceanic plate subducted below a continental plate. 

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Today, we continued the investigation of different mountains, which we started on Friday. Each group compiled its data and added it to a chart so we could better visualize the differences in the mountains. We compared different data and looked for relationships. For example, does the age of the mountain have anything to do with whether it is growing or shrinking? Does the location of the mountain have a relationship to the direction it is moving? 

After all the classes shared their data, I saved it to be added to the world relief map I had posted at the back of the room. We'll be using the map in the upcoming weeks as we investigate more possible reasons for the changes to the Earth's surface.

Next, we looked at the charts from last week's initial models of the ideas the kids had about what might be causing changes in the mountains. The kids added questions to their slides from last week's Notice & Wonders. The most common questions were about tectonic plates. We discussed where to start our exploration of changes in the Earth's surface by trying to figure out what tectonic plates have to do with earthquakes. 

I showed a quick video that shows someone who experienced an earthquake on Mount Everest and how he was involved in gathering information from seismometers in the area. 

Then, we watched a video of an earthquake that happened closer to home. In 2019, there was a 6.4 magnitude earthquake that hit Ridgecrest, California. About 36 hours later, a 7.1 aftershock affected the same place. Scientists are trying to figure out why the initial earthquake was less powerful and why there was such a large gap of time between them. We analyzed the movement of the cars in the video. I asked how many of the kids remember the earthquake that happened here on October 8, 2023. Some remember it, but weren't thinking about the way it moved. I was very excited when I felt it because I could identify the P-wave and S-wave. We will be learning more about those soon, but for now, I pointed out the initial jarring up and down movement of the P-wave, followed by the side-to-side motion of the S-wave in the video.

We looked at the damage done to the surface of the Earth from a satellite view. The kid could see where the Earth cracked and shifted. One picture shows a road that shifted so much that you wouldn't be able to drive from one side of the desert to the other. Tomorrow we will continue to investigate what might be causing these changes.

This is an opinion at this point. Some examples of answers the kids gave:

They are big hills, they are rocks, and snow. They got there when the Earth was made (this was hard for most kids to explain).

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We finished brainstorming reasons why mountains change with how mountains shrink. Many suggestions were the same as how they grow and move (plate tectonics, earthquakes, sea level changes, erosion, etc.), but most classes added volcanic eruptions. Living in this area, many kids know that Mount Saint Helens was once much taller than it is now because of the eruption in 1980. 

We started exploring mountains around the world and what makes them different. Groups were assigned a different mountain and given some cards with facts about the mountains. One person in each group made a copy of a slide (to save paper, but here's what was on the slides: Mountain Case Studies), to record information they found. On Monday, we will locate the different mountains on the map, and the groups will share the information they found, so we can compare the mountains.