What's Under Your Feet?

Open with the driving question and a cutaway view of Earth's layers, naming crust, mantle, outer core, and inner core so the learner sees what lies between the surface and the planet's center.

• Surface features look solid but sit on a layered planet
• Crust, mantle, outer core, inner core each have a role
• Question: how can the inside shape the outside?

One-question prediction: ask the learner to choose what they think is the main driver of mountains, earthquakes, and ocean basins before any explanation is given.

• Commit to an initial hypothesis
• Surface weather vs. forces from deep inside

Simulation where the learner adjusts a heat slider at the core and watches mantle convection speed change, visualizing how deeper heat transfers upward through the rock.

• Core heat rises through the mantle
• Hot rock rises, cool rock sinks — a slow conveyor
• Convection speed responds to temperature

A world map showing the major tectonic plates, with arrows indicating motion direction at boundaries, giving visible evidence that the surface is fractured and moving.

• Earth's crust is split into plates
• Plates carry continents and ocean floor
• Boundaries are where surface change concentrates

Explain how mantle convection currents drag the lithosphere, cause plates to collide, pull apart, and slide, and how each motion type produces a different surface feature.

• Convection currents tug on plates from below
• Convergent boundaries build mountains and volcanoes
• Divergent boundaries open ocean basins
• Transform boundaries cause earthquakes

Side-by-side simulation comparing convergent, divergent, and transform plate motions, showing the resulting surface features for each so the learner can match cause to effect.

• Each boundary type produces a distinct landscape
• Mountain ranges form where plates converge
• Mid-ocean ridges form where plates diverge
• Fault lines form where plates slide past

Transfer test: the learner is shown an unfamiliar landscape — a deep ocean trench, a volcanic island arc, or a mid-ocean ridge — and must identify which boundary type created it.

• Apply plate motion logic to a new scene
• Trenches and arcs come from convergence
• New ridges come from divergence

Mark the boundary of the explanation: wind, water, and ice reshape the surface too, but they work on top of features already built by Earth's interior — the layered dynamics are the first cause, not the only one.

• Surface erosion modifies, it does not originate, continents
• Layered interior dynamics are the deep cause
• Weathering is a follow-up process, not the driver

Resolve the driving question: heat-driven convection in the mantle moves the crustal plates, and the type of plate motion at each boundary directly determines whether the surface builds up, splits apart, or slips and shakes.

• Core heat powers mantle convection
• Convection drives plate motion
• Plate boundaries create mountains, oceans, quakes, and volcanoes
• The solid-feeling ground is the moving top of a layered system