DO NOW 1. _____protects humans from the ultraviolent radiation from the sun(air pollution) 2. _____ fossil fuel used to make plastic (fossil fuels) 3. _____ heat from inside the Earth(alternative energy) 4. _____ cutting down all the trees in an aarea (human impact) 5. _____plant trees around a field to prevent soil erosion(soil conservation) 2.What layer of the soil profile is made of partially weathered bedrock?

Key Questions Plate Tectonics 1. What is seafloor spreading? 2. What is the theory of plate tectonics? 3. What are lithospheric plates? 4. What makes tectonic plates move? 5. What are convection currents?

What is seafloor spreading? 1. Seafloor spreading- the process by which new oceanic lithosphere is created and old is pulled down

What is plate tectonics? 2. Plate tectonics is the theory that the Earth’s lithosphere (crust) is divided into tectonic plates that move around on top of the asthenosphere (upper mantle)

What are tectonic plates? 3. Lithospheric plates are huge slabs of rocks that float on top of the asthenosphere.

4. Plates move because of Heat and gravity Ridge Push Slab pull Convection Currents

5. Convection Currents (warm materials rise and cool materials sink)

How Plates Move: Convection Currents When any fluid is heated there is a natural tendency for the hotter material to expand (thus making it less dense) and rise to the surface. At the surface it loses heat and travels sideways, eventually cooling, becoming more dense and sinking. The process repeats itself, with the fluid moving round and round in convection cells

. How Plates Move: Convection Currents Convection Currents