Tectonic Plate Forces Driving Earth's Movement

Understanding the forces that shape our planet Slab pull, ridge push, and convection currents Year 10 Earth Science

What Makes the Earth Move?

Think about earthquakes and volcanoes you've heard about What forces could be powerful enough to move entire continents? Share your ideas with a partner

Earth's Structure Review

Crust - thin outer layer where we live Mantle - hot, semi-solid rock layer Outer core - liquid iron and nickel Inner core - solid iron and nickel

What Are Tectonic Plates?

Large pieces of Earth's crust and upper mantle Float on the semi-solid mantle below About 15 major plates worldwide Constantly moving - very slowly!

Major Tectonic Plates of the World

The Power Beneath

The Earth's interior is like a giant heat engine, driving the movement of tectonic plates through three main forces

Three Forces Drive Plate Movement

1. Convection currents - heat-driven circulation in the mantle 2. Slab pull - dense oceanic plates sink into the mantle 3. Ridge push - new crust pushes older crust away

Force 1: Convection Currents

Heat from Earth's core warms the mantle Hot mantle rock rises toward the surface Cool mantle rock sinks back down Creates circular flow patterns

Modeling Convection

Imagine you're stirring honey that's being heated from below Hot honey rises to the top Cool honey sinks to the bottom This creates a circulation pattern - just like in Earth's mantle!

Where Convection Currents Work

Occur throughout the mantle layer Most active in the upper mantle (asthenosphere) Drag tectonic plates along as they move Like a conveyor belt beneath the plates

Force 2: Slab Pull

Occurs at subduction zones Dense oceanic plate sinks into the mantle Gravity pulls the sinking slab downward Drags the rest of the plate behind it

Why Do Oceanic Plates Sink?

Think about density Oceanic crust vs continental crust What happens when you put a rock in water?