What are the three different ways tectonic plates can interact with one another? Is ocean floor closer to a ridge younger or older than floor further away? Why? What two devices helped scientists map the ocean floor? What is the deepest trench in the world named? How deep is it? Pg. 87 Convection- the movement of heat in a circular fashion where hot matter is rising and being replaced by cooler matter Denser matter sinks while less dense rises Thought to be the driving mechanism of plate movements Flow only at a few cm per year An uplifted ridge pushes the ocean plate toward a trench at a subduction zone (called ridge push) Horizontal movement at the top of a c.c. creates a drag of the crust creating plate motion When the crust is pulled into a subduction zone, it is known as slab pull How do convection currents originate and how large are they Are they permanent features or do they shift What causes divergent boundaries on continents like the Great Rift Valley in Africa Create your own diagram showing the convection processes in the mantle that drive ridge push and slap pull. Be sure to include a ridge, a trench and the correct direction of convective flow. You will have to label a diagram on your next test.