Causes of Plate Movement PDF

Causes of Plate Movement Learning Competency To be able to describe the possible causes of plate movement Which emoticon best describes your feeling today?  ACTIVITY 1 Fill in the chart  Solid Molten rock 6000 °C 1220 km Solid metal 3200 °C 0-400 °C Semi-solid...

Causes of Plate Movement Learning Competency To be able to describe the possible causes of plate movement Which emoticon best describes your feeling today?  ACTIVITY 1 Fill in the chart  Solid Molten rock 6000 °C 1220 km Solid metal 3200 °C 0-400 °C Semi-solid 2300 km Liquid metal Rock 5000 °C Liquid 0-60 km 2900 km Solid  ACTIVITY 2 Simulating plasticity of earth’s mantle Post-Laboratory Discussion How does the cornstarch change as you add water? What happens when you press down slowly on the cornstarch?  What happens when you squeeze the mixture in your hand and then release your grip? Describe the properties of the cornstarch mixture. Would you call it a solid or liquid? How is the cornstarch- and-water mixture similar to the Earth’s mantle? Causes of Plate Movement  What causes tectonic plates to move? Mantle Convection Ridge push Slab pull  ACTIVITY 3 Convection in the mantle vocabulary  TMNAEL MANTLE A layer beneath where the less dense hot molten material rises and sinks  THPREHAEOSENS ASTHENOSPHER E A soft, weak and plastic-like layer, the upper part of the mantle where lithospheric plates float and move.  MMGAA MAGMA Hot molten rocks formed beneath the Earth’s surface NOITCEVNOC CTUNRRE CONVECTION CURRENT Facilitates the movement of the lithospheric plates.  ORCE CORE The innermost layer of the Earth, which generates heat to the mantle  ACTIVITY 4 Video analysis What happens during convection?  A temperature increase produces a decrease in the density of a substance Density is defined as mass divided by volume (D=m/V) Less dense substances float on more dense substances Convection is defined as the circulation of a fluid at a non-uniform temperature due to the variation of its density and the action of gravity  COLD, HIGHER DENSITY Hot Cool rising Cool descending current descending current current HOT, LOWER DENSITY Circular Paths of Food Coloring Gel Created by Convection Currents in Heated Water Water at the bottom is warmer and less dense; food coloring gel rises Water at the top is cooler and denser; food coloring gel sinks  This theory was proposed by Arthur Holmes in 1929. Holmes suggested that as the mantle becomes heated, its density decreases and eventually rises up. He added that when the material cools, it would sink, exhibiting a circling behavior that he described like a conveyor belt. According to Holmes, the pressure of the heated magma broke the continents apart forcing the pieces to drift in opposite directions.  ACTIVITY 5 Lithospheric float Based on the picture,  What represents the plates?  What represents the mantle?  Where is the heat source?  Why are the blocks of wood floating?  Which part of the water has a greater density? Lesser density?  ACTIVITY 6 Let’s do this way  Based on what you have learned, relate the mechanism happened in slab pull and ridge push interactions.  Despite the fact that it is recognised that SOME type of convection is responsible for the BASIC movement of plates, this theory of convection currents causing plate movement is now largely out of favour, with modern imaging techniques unable to identify convection cells in the mantle sufficiently large enough to drive plate movement. As a result, plate movement is thought to depend on other factors: 1) ‘Slab pull’: newly formed oceanic lithosphere at a mid ocean ridge is less dense than the asthenosphere, but becomes denser with age at is cools and thickens. This causes it to SINK into the mantle with a downward pull at subduction zones as a result of gravity. The end of the plate is colder and older. 2) ‘Ridge push’: An ocean ridge represents a large volume of warmer, less dense material. The force is a lateral(sideways) movement as this warmer less dense ridge material expands and exerts a sideways push on the adjacent plates.  ACTIVITY 7 Check your understanding Convection heat density temperature rise less sink more magma current lithospheric asthenosphere  How Tectonics Description of Movement What causes Plates Move tectonic plates to 1. Convection move? Mantle Convection 2. Ridge Push Ridge Push Slab Pull 3. Slab Pull hank you for listenin