Download Section 17.4 Convection Currents

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: – The movement of a fluid, caused by differences in temperature, that transfers heat from one part of the fluid to another.

• Density: – The amount of mass in a given space; mass per unit volume.

• Heat Transfer: – The movement of energy from a warmer object to a cooler object.

Vocabulary • Radiation: – The transfer of energy through empty space.

• Conduction: – The transfer of heat by direct contact of particles of matter.

• Convection: – The transfer of heat by movements of a heated fluid.

Introduction • List the three types of heat transfer. – Radiation – Conduction – 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 temperature and density differences of ____________ within a fluid. • A measure of how much mass there is in a density 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.

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. – True

• True or False: The heat source for the convection currents in the mantle is the sun. – False

Convection in Earth’s Mantle • 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