Plate Movement
Plate Movement
This page provides an in-depth look at plate movement and all its known causes. It's best to start without sharing the objectives because following the map activity, the gallery activity introduces the key ideas through images that students need to connect. Following this students work their way through several well-chosen videos, animations, images and text-based resources to complete several visually impressive worksheets, on Earth's structure, causes of plate movement, rifting and mantle plumes.
Enquiry Question
What causes tectonic plates to move?
Lesson Time: 1 Hour
Lesson Objectives:
- To explain the mechanisms of plate movement including internal heating, convection currents, plumes, subduction and rifting at plate margins
Teacher Notes:
tarter - Plate Movement Map - This simple stater map familiarizes students with the plates and plate boundaries and gets them thinking of plate movement by adding the missing arrows. In addition, what are most plate boundaries jagged and uneven?
Plate Movement Processes - Students should study the gallery of images and then decide what connects them. Quick activity. Repeat the gallery and then students should identify the process it shows. (answers in the drop-down box)
A History of Plate Movement - This video can be used to reinforce the learning above
Earth's Structure Worksheet - Students can then add the labels to the Earth structure diagram
Heat Sources and Convection Cells - Watch the next two videos and students should make notes on the sheet provided.
Plenary on Plate Movement - Drag and drop the sentences into the sequence to explain plate movement. These activities don't always have an exact answer but are useful to get the students actively reading the text.
Rifting Animation - Students should then watch the rifting animation and complete notes to explain the sequence of processes based on the screenshot images
Mantle Plumes and Hotspots - You can introduce students to hotspots through the gallery, students can simply make notes on the chalk and talk.
Exam Question Hotspots - A common question is hotspots - in this question only 4 marks are available and it requires the use of the diagram. Good to practice these often
Student Assessment - There is a clear brief for this 6-mark question to explain plate movement
Student Textbook Links
Starter Activity - Plate Movement Map - Processes and Spatial Interactions
- Study the map of plate boundaries on the PDF and complete the map with the missing arrows to show plate movement
- Referring to the map discuss why the plate boundaries appear to be so jagged and uneven
Student Activity - What connects the images? Processes
Study the gallery and decide what connects all the images.
- Image 1 - Convection cells
- Image 2 - Radioactive decay
- Image 3 - Meteorite collisions forming Planet Earth
- Image 4 - Slab Pull at subduction zones
- Image 5 - Ridge Push at divergence zones
- Connecting factors - reasons why plates move
Student Activity - A History of Plate Movement - Processes and Spatial Interactions
Watch the following video showing the history of plate movement and continentality (watch up to 3.40mins)
Student Activity - The Mechanisms of Plate Movement? Processes
- Study the diagram of the Earth's structure and add the numbered box to the correct place on the diagram
Student Activity - Heat Sources and Convection Cells - Processes
Watch the two videos and make the transcript notes on the worksheet
Follow up the videos with the following sorting activity
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Once cooled sufficiently, rising magma will cease to rise but is forced sideways by rising magma below
As magma rises and cools it vertical movement slows down
Eventually cooled magma is forced to fall.
If rising magma is in contact with the crust it forces plate movement. In other areas this creates fresh oceanic crust and a process called ocean floor spreading.
Elements that are warmer than elements above it are forced to rise.
Rising elements within the mantle create mantle plumes
The core is immensely hot due to primordial heat.
Unstable elements within the core decay over time and heat is produced from radioactive decay
Heat Sources and Convection Cells
Student Activity - Ridge Push and Slab Pull Processes - Processes
Study the following diagram and suggest how it helps explain plate movement
Read the text below and annotate the diagram to explain the process of Ridge Push and Slab Pull
Ridge Push
The lithosphere thickens with distance (and time) away from the mid-ocean ridge. This is because it cools as it moves away from the ridge and the boundary between the solid lithosphere and the plastic asthenosphere becomes deeper. The result of this thickening with distance from the ridge is that the lithosphere/asthenosphere boundary slopes away from the ridge. The weight of the lithosphere on this sloping surface produces a downslope force. And since the asthenosphere is weak, the weight of the lithosphere near the ridge sliding down the asthenosphere "pushes" the older part of the plate in front of it
Slab Pull
As lithospheric plates move away from mid-ocean ridges they cool and become denser. They eventually become more dense than the underlying hot mantle. At a subduction zone, the denser of the two plates sinks under the less dense plate. During subduction, cool, dense lithosphere sinks into the mantle under its own weight, because it is denser than the mantle around it the process of subduction will continue. Therefore the weight of the subducting plate and the force of gravity drive its movement. Slab pull is considered the most important factor causing plate movement.
Student Activity - Plumes - Processes
Study the following gallery showing mantle plumes and hotspots and annotate the diagrams in the worksheet to describe the characteristics of hotspots and to describe how they show plate movement.
Exam Question - Hotspots - Processes
With the use the diagram (2) explain the evidence to explain the presence of hotspot volcanoes (4 marks)
Explain two processes that explain plate movement (3+3)
To address this question responses should consider the role of convection cells, ridge push processes and slab pull. To gain the 3 marks responses should clearly locate the process within the mantle and/or plate boundary. The process should be accurately explained and clearly linked to how this leads to plate movement