Lesson 8 — Earthquakes and Volcanoes 1 / 7

The ground beneath your feet feels solid and still. But Earth's surface is being reshaped all the time — sometimes slowly, sometimes in violent seconds. Today we find out how.

Earth isn't solid rock all the way down. It's built in layers, like a giant peach — and the thin outer skin is broken into giant moving pieces.

LayerWhat it's likeHow thick / deep
CrustThin, solid rock — where we live5–70 km thick
MantleHot, slow-flowing rock~2,900 km thick
Outer coreLiquid metal (iron & nickel)~2,200 km thick
Inner coreSolid metal, ~5,500°Ccentre of the Earth

Where plates meet, the action happens. Watch how a volcano works: lava rises and fills the vent, then spills over the top as it erupts.

magma chamber Lava rises through the vent and erupts
Underground, melted rock is called magma. Once it erupts onto the surface, we call it lava.

Earthquakes and volcanoes don't happen just anywhere — they cluster along the edges where tectonic plates meet, almost all around the Pacific Ocean.

EQUATOR PACIFIC OCEAN ATLANTIC INDIAN OCEAN N. AMERICA S. AMERICA EUROPE AFRICA ASIA AUSTRALIA The Pacific Ring of Fire = major earthquake & volcano zone
The red markers trace the Ring of Fire — a horseshoe-shaped zone around the Pacific Ocean where most of the world's earthquakes and volcanoes occur.

In your groups, model Earth's moving crust with clay — then describe how each event reshapes the surface.

EventHow it changes the surface
Volcanic eruptionAdds new rock and ash; can build whole islands
EarthquakeCracks and shifts the ground; can trigger landslides
Erosion (after)Wind and water slowly wear the new land down again

On your own, complete the volcano worksheet. Use the diagram from earlier as your guide.

Think-pair-share to finish.