Warm-Up 1.What are the three types of plate boundaries? 2.Describe the direction of movement of these boundaries.

Chapter 17 Plate Tectonics Section 17.4 Convection Currents and the Mantle

Vocabulary Convection Current: –T–The movement of a fluid, caused by differences in temperature, that transfers heat from one part of the fluid to another. Density: –T–The amount of mass in a given space; mass per unit volume. Heat Transfer: –T–The movement of energy from a warmer object to a cooler object.

Vocabulary Radiation: –T–The transfer of energy through empty space. Conduction: –T–The transfer of heat by direct contact of particles of matter. Convection: –T–The transfer of heat by movements of a heated fluid.

Introduction List the three types of heat transfer. –R–Radiation –C–Conduction –C–Convection

Radiation What are two forms of radiation? –Forms of radiation include the heat you feel from sunlight and the heat you feel around a flame or open fire.

Conduction What is an example of conduction? –An example of conduction is a spoon heating up in a pot of hot soup or the skin of your hand heating up when you touch a hot spoon.

Convection Heat transfer by convection is caused by differences of ____________ and density within a fluid. A measure of how much mass there is in a volume of a substance is ____________. If a pot of soup is no longer heated, when will the convection currents stop flowing? –The convection currents will stop flowing when all the soup has reached the same temperature. temperature density

Convection Circle the letter of the sentence that describes what happens to a fluid when its temperature increases. –A. Its particles occupy less space –B. Its density decreases. –C. Its particles move more slowly. –D. Its particles settle together more closely.

Convection in Earth’s Mantle True or False: Convection currents flow in the asthenosphere. –T–True True or False: The heat source for the convection currents in the mantle is the sun. –F–False

How is mantle convection related to the movements of tectonic plates? –The process associated with convection currents in the mantle that occurs when the weight of an elevated ridge pushes an oceanic plate toward a subduction zone is called ridge push –Another process that occurs as the weight of the subducting plate pulls the trailing lithosphere into a subduction zone is called slab pull

Convection in Earth’s Mantle