lesson3_convection.pdf

PLATE TECTONICS and Large-Scale System Interactions  Learning Objectives -describe convection current, Slab Pull and Ridge Push; and -explain what causes the tectonic plates to move  PRACTICE TASK Identify which among the images shows the presence of convection current ( ) and...

PLATE TECTONICS and Large-Scale System Interactions  Learning Objectives -describe convection current, Slab Pull and Ridge Push; and -explain what causes the tectonic plates to move  PRACTICE TASK Identify which among the images shows the presence of convection current ( ) and put a cross ( ) if convection current does not apply in the process PRACTICE TASK boiling water PRACTICE TASK boiling water PRACTICE TASK warming of spoon PRACTICE TASK warming of spoon PRACTICE TASK rising of hot air balloon PRACTICE TASK rising of hot air balloon PRACTICE TASK burning of wood PRACTICE TASK burning of wood PRACTICE TASK melting of ice PRACTICE TASK melting of ice MYSTERY ENVELOPE Let’s open?  MYSTERY ENVELOPE -identify what is inside -how is it useful to you as a student? MYSTERY ENVELOPE MYSTERY ENVELOPE -a mark, or sign -indicates direction -a pointer WATCH CLOSELY  WATCH CLOSELY What was the heat source in the set-up?  WATCH CLOSELY As the contents above are being heated, how does the thyme leaves behave? WATCH CLOSELY -What represent the plates? -What represents the mantle? WATCH CLOSELY -Why are the block of woods floating?  CONVECTION -heat transfer conduction radiation  CONVECTION -warm air rises, cooler air sinks less dense denser -less dense fluid rises away from the heat source  CYCLE -warm air rises, cooler air sinks SOURCE  CYCLE -cycle stops when heat is evenly distributed throughout the fluid  CYCLE SOURCE decayed radioactive elements from the core NEW PROPOSAL ARTHUR HOLMES -Theory of Mantle Convection  SLAB-PULL THEORY -states that GRAVITY and the plates themselves are the ones responsible for the plate tectonics through the subduction process SLAB-PULL THEORY  SLAB-PULL THEORY -A very dense slab will sink faster than a less dense slab because of the gravitational pull and it will exert greater force on the plate attached to it. SLAB-PULL THEORY  RIDGE PUSH -the primary evidence is comparing rates of seafloor spreading along the ridge segments having different elevations  RIDGE PUSH -spreading rates along the Mid- Atlantic Ridge are considerably LESS than spreading rates along the steep East Pacific Rise RIDGE PUSH  RIDGE PUSH Mid-Atlantic East Pacific Ridge Rise MANTLE DRAG MANTLE DRAG QUESTIONS?