Convection in the Mantle I. Types of Heat Transfer A. Radiation B. Conduction C. Convection II. Convection Currents III. Convection Currents in the Mantle Convection in the Mantle

What We Want To Know What causes the plates to move? THE answer to this question we believe is: convection currents in the mantle. animation

Convection Convection- heat transfer by the movement of currents within a fluid Caused by differences of temp. and density within the fluid

Convection Currents in Earth 1. What is the heat source? 2. What is flowing? Heat from the core and the mantle itself causes convection currents in the mantle. Google Image Result for http://www.windows.ucar.edu/earth/interior/e_thermal_history_animated.gif

Convection Currents in the Earth Animation As the convection currents move through the mantle, it causes the plates to move in the lithosphere.

Science Starter: WED WK6 Along with increasing density, what force will help a convection current fall back towards the core? Science Starter: WED WK6

Welcome To Science Plate Tectonics Test will be Friday For WEDNESDAY: Graham Crackers and White Frosting for extra credit Welcome To Science

What does this map show you? Tectonic Plate Boundaries What does this map show you?

Tectonic Plate Boundaries 3 Types What direction they move? What features & processes their movements cause? Tectonic Plate Boundaries

Today’s Objectives 1. Complete Convection Experiment 2. Begin the final section Today’s Objectives

Tectonic Plate Boundaries

Types of Plate Boundaries Divergent Boundary- 2 plates move apart Most DB’s are at mid-ocean ridges. On land DB’s form deep valleys called rift valleys Fig. 19.21 - Evolution of a Divergent Plate Boundary Types of Plate Boundaries

Divergent Boundary

Convergent Boundary 2 plates collide The more dense plate will subduct under the less dense plate Common Features 1.Mountains 2. Volcanoes 3. Deep-Ocean Trenches Convergent Boundary

Types of Convergent Boundaries

Types of Convergent Boundaries

Types of Convergent Boundaries

2 plates slip past each other in opposite directions. Transform Boundaries = Earthquakes Observe animations of processes that occur along plate boundaries. animation Transform Boundary

Subduction at Trenches Deep-ocean trench- underwater canyon where ocean crust sinks into the mantle. Subduction- process by which ocean crust sinks beneath a deep-ocean trench and back into the mantle Subduction Animation - Earthguide Online Classroom

Matching Game Convergent boundary Sea-floor spreading Plate tectonics land masses have slowly moved over time Plates move on top of asthenosphere Two plates slip past each other in opposite directions Happens at divergent boundaries, allows magma to rise to the ocean floor Two plates collide with each other Two plates separate with each other Matching Game Convergent boundary Sea-floor spreading Plate tectonics Continental drift Divergent boundary Transform boundary