Assessment
Mechanisms of Movement Lab Report
Introduction
The movement of Earth’s plates is explained by the theory of plate tectonics. The theory has been around for quite some time, but as you will discover in your exploration, it was ignored because the mechanism by which this phenomenon occurred could not be explained.
So, what is plate tectonics, you ask? In a nutshell, the theory states that all the continents and Earth’s crust “float” on a flowing, moving mantle. This movement has broken the crust of Earth into several major plates, or sections, and several minor sections. The movement of these large sections of the crust results in events like mountain building and earthquakes.
In this lab, you will investigate a model that resembles the movement of Earth’s plates. When you are finished, you will write a laboratory report of your results.
Problem:
What happens to the asthenosphere as lithospheric plates move at the three types of plate boundaries?
Hypothesis:
Review the virtual lab demonstration in the lesson and stop the video when prompted to formulate a hypothesis. Hypothesize what will happen to the “plates” outside of your egg when you move them towards, away from, and past one another.
Materials:
Watch the virtual lab demonstration video within the lesson. No additional materials are needed.
Optional: If you wish to perform the lab in the video demonstration, the materials are listed below.
water
pan
raw egg
a cracking device such as a teaspoon
paper towels or newspaper
Procedures:
Watch the Tectonic Egg Virtual Lab Demonstration Video within the lesson and record your observations in Table 1.
Complete the Questions and Conclusion section of the lab report.
Optional Procedures.
If you would like to perform the lab in the video demonstration, perform steps 2 through 8 under adult supervision.
Boil an egg until all parts are cooked (about 10 minutes).
Pour the water off and allow the egg to cool. You can put the egg in cold water to cool it more quickly.
Once the egg is cool, use a tracking device, such as a teaspoon, to lightly tap the shell in several places so there are several large cracks in the shell. Do not make too many cracks. There should be several large pieces of eggshells.
Place the egg on a layer of paper towels or newspapers.
Try to move the pieces of the cracked eggshell around on the surface of the egg. (Don’t remove them; just see if they slide around.) There should be slight motion allowed by the membrane holding the shell to the rest of the egg inside.
Next, find two sections of the egg that are large and on opposite sides of a crack. Use your index fingers and gently pull the two sections away from each other. Observe what happens within and around the crack between the pieces. Record your observations in Table 1.
Stay in the same area of the egg and push the two pieces toward each other. Observe what happens within and around the crack. Record your observations in Table 1.
Stay in the same area of the egg and try to slide one section of the shell up or away from you and pull the other down or toward you. Observe what happens within and around the crack. Record your observations in Table 1.
Variables:
For this investigation, list the independent, dependent, and controlled variables.
Data and Observations:
Table 1: Tectonic Egg Movement
Movement
Observations
eggshell pieces pushed towards one another
eggshell pieces pulled away from one another
eggshell pieces pushed past one another
Questions and Conclusion
If the egg is a model of Earth, what does each part of the egg represent? (Use the chart below.)
Portion of Egg
Part of the Earth It Represents
Whole egg
Eggshell
Cracked pieces of eggshell
Egg white
Egg yolk
How does your model demonstrate the differences between the types of tectonic plates and the resulting observations in the asthenosphere?
How did your hypotheses of your Tectonic Egg Model compare to your experimental results?
What are some shortcomings of using this model as a replicable of the Earth? Suggest a way that a scientist could create a more accurate model of Earth’s tectonic plates.
Before completing this lab activity, you should be able to:
explore how the plate tectonic theory evolved from the earlier continental drift hypothesis
investigate the mechanisms of movement in the asthenosphere that cause plates to move
examine the three types of plate boundaries: divergent, convergent, and transform
After completing this lab activity, you should be able to:
describe the three types of plate boundaries
explain the mechanisms of movement in the asthenosphere that cause plates to move
Mechanisms of Movement Lab
In this lab activity, you will investigate a model that resembles the movement of Earth’s plates. Review the Mechanisms of Movement Lab Report. Then record your observations as you watch the video demonstration below. Submit your completed lab report to your instructor for grading. Review this Grading Rubric before completing the lab activity.
09.03 Mechanisms of Movement
Please view the Grading Rubric before beginning the assessment.
Review all parts of the lesson, including the interactives.
Complete and submit the 09.03 Mechanisms of Movement assessment.
Mechanisms of Movement
You and your friends are playing a game. The game’s instructions say you have to match five images to make one complete image. The twist is that each image represents a continent or another major landmass in the Southern Hemisphere:
Pay attention to the coastlines of the continents and other major landmasses from the Southern Hemisphere.
the southern hemisphere continents spread out
Notice how the continents can be arranged to fit together.
the southern hemisphere continents fitted together
Show Text Version
In the early 20th century, a scientist named Alfred Wegener conducted research using a similar approach. He tried to match animals, plants, geologic structures, and climate regions along the coastlines of continents. Wegener believed Earth’s continents were formerly connected, fitting together like pieces of a jigsaw puzzle. Watch the following animation to see how the continents in both hemispheres seem to fit together like a puzzle:
Alfred Wegener was a German scientist with a question he thought could be answered using the approach shown previously: Do the coastlines of continents separated today show evidence that they once matched?
Wegener did find matching animal fossils and geologic structures on different continents. Based on his observations and those of other scientists, he proposed a hypothesis called continental drift. Wegener hypothesized that the continents were once joined together in a giant landmass, a supercontinent he called Pangaea.
Throughout the lesson, you will gather evidence for the theory of plate tectonics and continental drift. Use the following graphic organizer for recording notes on the information presented:
Graphic Organizer
The first step to understanding Wegener’s ideas is presented in the activity below. Use the activity to investigate Wegener’s continental drift idea:
Show Text Version
Wegener’s ideas were considered by the scientific community. Unfortunately, neither Wegener nor other scientists could explain how the continents moved across Earth’s surface. Because there was no easy way to explain how continents moved, most scientists of the time rejected Wegener’s ideas.
Wegener found evidence that supported his hypothesis. However, he was on the wrong track with his explanation of how continents moved. Wegener proposed that the continents were separate from the ocean floors. He suggested the continents themselves moved over and even though the ocean floor. Today, we know this view is incorrect.
Based on the work of Wegener and others, the idea of continental drift was refined. It later became known as the theory of plate tectonics. Based on additional evidence, scientists proposed a different mechanism to explain how the continents moved. In this model, Earth was made of giant rocky plates, called the lithosphere, which floated and moved on a molten inner portion of Earth, the asthenosphere. Conclusive evidence for mechanisms of the tectonic movement included differences in the magnetism and age of rocks on the ocean floor.
Use the following activity to investigate ocean-floor evidence for plate tectonic theory:
A diagram of magma rising from the lithosphere causing the ground above it to spread
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Today scientists universally accept the theory of plate tectonics. Modern evidence for tectonic movement includes volcanism, earthquakes, seafloor spreading, and evidence from satellite mapping. Satellites measure tectonic plate movement with high precision. Satellite measurements show that the Atlantic Ocean grows two to five centimeters wider each year, on average. That means North America and Europe are getting farther apart each year.
Use the following activity to review your understanding of the differences and similarities between continental drift and plate tectonics theory:
Another widely accepted piece of evidence for tectonic movement is the formation of the Hawaiian Islands and other oceanic volcanoes over a hotspot. A hotspot is a geomagnetically active region where volcanic material rises from the asthenosphere into the lithosphere. When a volcano rises from the ocean floor above the surface of the water, it forms an island. In the case of Hawaii, an active volcano, Kilauea, is located on the “Big Island.”
As you can see in the image below, the movement of Hawaii over a “hotspot” in the crust means that extinct volcanoes on older regions of the Pacific Plate have moved over time.
Hotspots in the Hawaiian islands. See text version.
Source: http://pubs.usgs.gov/gip/dynamic/hotspots.html
Grocery store belt and convection cell in the earth. See text version.
What do the two images shown above have in common?
Plates on Earth move as a result of convection deep within Earth. Recall that convection in the mantle of Earth results from the rising of hot rock material and the sinking of cooler rock material. The constant rise and fall of material leads to the formation of convection cells.
Use the following activity to understand how plates move on Earth.
Grocery store belt and convection cell in the earth. See text version.
What do the two images shown above have in common?
Plates on Earth move as a result of convection deep within Earth. Recall that convection in the mantle of Earth results from the rising of hot rock material and the sinking of cooler rock material. The constant rise and fall of material leads to the formation of convection cells.
Use the following activity to understand how plates move on Earth.
Use the following activity to further investigate divergent and convergent boundaries. Then investigate transform plate boundaries. Record information in your notes about the similarities and differences between the three types of plate boundaries:
Now that you have learned about the types of plate tectonic boundaries, try to recognize the types of motion in the following animations.
Type 1
Question: What type of plate tectonic boundary is shown in the animation?
Type 2
Question: What type of plate tectonic boundary is shown in the animation?
Type 3
Question: What type of plate tectonic boundary is shown in the animation?
Our maps of the world do not change today. But Earth’s landmasses did not always look the way they do now. As Wegener had proposed, landmasses were indeed part of one giant landmass called Pangaea. Pangaea was surrounded by a single big ocean known as the Tethys Ocean. By carefully studying rocks worldwide, scientists have gathered evidence to show how Earth’s tectonic plates have moved into the positions we see today.
View the following video to see how scientists think plates have moved over time:
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