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Energy Drives
Earth Changes

Explore how thermal energy, gravitational energy, and kinetic energy transform Earth's surface and interior over time.

Earth & Space Science

What Is Energy?

Energy is the ability to do work or cause change. In Earth science, energy is what moves tectonic plates, melts rock, drives weather systems, and reshapes landscapes. Energy cannot be created or destroyed: it only transfers and transforms.

Types of Energy in Earth Systems

Thermal Energy
Heat from Earth's interior and the Sun: drives convection, melts rock, powers volcanoes
Gravitational Energy
Pulls materials downhill: causes landslides, river flow, and tectonic plate subduction
Kinetic Energy
Energy of motion: wind erosion, ocean waves, earthquakes, and moving glaciers

Two Major Energy Sources

Sun Earth's Surface External: Solar Energy Radioactive Decay Internal: Geothermal Weather Erosion Waves Volcanoes Earthquakes

The Core Principle

1
Energy enters an Earth system (from the Sun or Earth's interior)
2
Energy transfers between materials (conduction, convection, radiation)
3
Materials change: they melt, erode, move, crystallize, or deform
4
Earth's surface and interior are reshaped over time

How Energy Transfers in Earth

Conduction Direct contact Heat flows through solid rock Convection Fluid circulation Hot mantle rises, cool mantle sinks Radiation Electromagnetic waves from the Sun heat Earth Metamorphism Rock transforms Plate Movement Tectonic shifts Weathering Surface breakdown Energy Transfer → Material Change

Constructive vs Destructive Processes

Constructive
Build up Earth's surface. Energy causes new landforms to form: volcanic eruptions add land, deposition creates deltas, mountain building from colliding plates.
Destructive
Break down Earth's surface. Energy wears away landforms: weathering cracks rock, erosion carries sediment, glaciers carve valleys, waves erode coastlines.

How to Model Energy-Driven Change

1
Identify the energy source: Is it solar (external) or geothermal (internal)?
2
Trace the energy transfer: How does energy move? Conduction, convection, or radiation?
3
Identify the material affected: What Earth material receives the energy? Rock, water, air, ice?
4
Describe the change: What happens? Melting, moving, breaking, depositing, crystallizing?
5
Classify the process: Is it constructive (building) or destructive (breaking down)?

Example 1: Volcanic Eruption

Magma Chamber Eruption Lava flow Lava flow New land forms as lava cools Thermal Energy (Radioactive decay)

Example 2: Water Cycle and Erosion

Sun Ocean Water absorbs heat Evaporation Cloud Rain Mountain Erosion Deposition

Example 3: Convection Moves Plates

Crust (Plates) Plate A Plate B Mantle (Semi-Molten Rock) Hot rises Hot rises Core: Source of Thermal Energy

The Rock Cycle: Energy in Action

Igneous Rock Sedimentary Rock Metamorphic Rock Magma/Lava Weathering (Solar energy) Heat + Pressure Melting Cooling Heat + Pressure

Energy and Temperature Changes

When thermal energy is added to Earth materials, their temperature rises. If enough energy accumulates, materials undergo a phase change: solid rock melts into magma, liquid water evaporates into vapor, or ice melts into liquid.

Solid → Liquid
Rock melts to magma at ~700-1200 °C deep underground
Liquid → Gas
Water evaporates when solar energy heats it to 100 °C
Gas → Liquid
Water vapor condenses as it loses energy, forming clouds

Common Mistakes

✕ Energy Is Created
Energy is not created during earthquakes or eruptions. It is transferred from stored thermal or gravitational energy into kinetic energy.
✕ Only Heat Matters
Gravity is also critical. Erosion, landslides, and subduction all depend on gravitational potential energy, not just thermal energy.
✕ Ignoring the Sun
Many students focus on internal energy only. The Sun powers the entire water cycle, weather systems, and most surface erosion processes.

Energy and Earth Summary

Process Energy Source Transfer Type Result
Volcanic Eruption Geothermal Convection Constructive
Weathering/Erosion Solar Radiation Destructive
Plate Tectonics Geothermal Convection Both
Water Cycle Solar Radiation + Convection Both
Metamorphism Geothermal Conduction Constructive
Landslide Gravitational Kinetic transfer Destructive

Question 1 of 5

What is the primary energy source that drives weathering and erosion on Earth's surface?

Question 2 of 5

A volcano erupts and lava flows down its sides, cooling into new rock. This process is best described as:

Question 3 of 5

In the mantle, hot rock rises toward the surface while cooler rock sinks. This movement is an example of energy transfer by:

Question 4 of 5

A student builds a model showing how a river carries sediment from mountains to the ocean, forming a delta. Which step correctly identifies the energy source and type of process?

Question 5 of 5

The equation \( Q = mc\Delta T \) describes how thermal energy relates to temperature change. If the same amount of energy \( Q \) is added to two different masses of rock, the rock with the smaller mass will: