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Matter & Energy
Flow in Earth Systems

Discover how matter cycles and energy flows through Earth's interconnected systems: the geosphere, hydrosphere, atmosphere, and biosphere.

Earth & Space Science

What Are Earth's Systems?

Earth is made up of four major interconnected systems. Matter and energy constantly move between them, shaping everything from weather to ecosystems.

Geosphere
All solid rock, soil, and minerals: Earth's crust, mantle, and core
Hydrosphere
All water: oceans, rivers, glaciers, groundwater, and water vapor
Atmosphere
The blanket of gases surrounding Earth: nitrogen, oxygen, \(\text{CO}_2\)
Biosphere
All living things: plants, animals, fungi, bacteria, and their habitats

Defining Matter and Energy

Matter
Anything that has mass and takes up space. Atoms and molecules: water (\(\text{H}_2\text{O}\)), carbon dioxide (\(\text{CO}_2\)), minerals, and organic compounds.
Energy
The ability to do work or cause change. Forms include thermal (heat), radiant (light), chemical, kinetic, and potential energy.

Why Does This Matter?

Understanding matter and energy flow helps us explain real-world phenomena: climate change, nutrient cycling, weather patterns, and ecosystem health.

1
Climate: Carbon moving between atmosphere and geosphere drives global temperature changes.
2
Ecosystems: Plants convert sunlight into chemical energy, feeding entire food webs.
3
Weather: Solar energy heats water, which evaporates and cycles through the atmosphere.

The Core Principle

Sun Radiant Energy Earth Systems Geosphere Hydrosphere Atmosphere Biosphere Matter Cycles (recycled) Heat Lost to Space Energy Flows (one-way)

Conservation of Matter

The Law of Conservation of Matter states that matter cannot be created or destroyed: it only changes form. In a chemical equation, atoms on the left must equal atoms on the right.

Energy Transformations

Energy changes form as it moves through Earth's systems. At each transformation, some energy is lost as heat, making the process one-directional.

Radiant (Sunlight) Chemical (Plant Sugars) Kinetic (Animal Motion) Thermal (Heat to Space) heat loss heat loss Energy degrades at every step: useful energy decreases

Cycling vs Flowing

Matter (Cycles) Energy (Flows)
Direction Circular: reused repeatedly One-way: enters, transforms, exits
Conservation Total amount stays the same Degrades to heat at each step
Source Already present in Earth Primarily from the Sun
Example Water evaporates, condenses, falls as rain Sunlight warms ground, radiates as infrared
Key Law Conservation of Mass Conservation of Energy (thermodynamics)

The Water Cycle: Matter in Motion

Ocean / Lakes Evaporation (+ solar energy) Atmosphere Condensation (releases heat) Clouds Precipitation Land / Soil Runoff / Groundwater

The Carbon Cycle: Connecting All Systems

Atmosphere (\(\text{CO}_2\))
Plants Animals Fossil Fuels (Geosphere) Decomposers Oceans Photosynthesis Respiration Combustion Dissolves

How to Trace Matter & Energy

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Identify the system: Which sphere(s) are involved? (geosphere, hydrosphere, atmosphere, biosphere)
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Track the matter: What substance is moving? (water, carbon, nitrogen, minerals) Where does it start and end?
3
Track the energy: What form does energy take at each step? (radiant, chemical, thermal, kinetic)
4
Find the heat loss: At which transformation does energy degrade into thermal energy?
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Verify conservation: Does total matter in = total matter out? Does energy degrade but remain accounted for?

Example 1: Photosynthesis

Scenario: A tree absorbs sunlight and \(\text{CO}_2\) from the atmosphere, plus \(\text{H}_2\text{O}\) from the soil, to produce glucose.

Energy In
Radiant energy from sunlight is absorbed by chlorophyll in leaves
Matter In
\(\text{CO}_2\) from atmosphere + \(\text{H}_2\text{O}\) from hydrosphere/geosphere
Transformation
Radiant energy converts to chemical energy stored in glucose (\(\text{C}_6\text{H}_{12}\text{O}_6\))

Example 2: Food Web Energy Flow

Scenario: Grass captures sunlight. A rabbit eats the grass. A hawk eats the rabbit. Trace energy and matter through this food chain.

Sun Grass 100% energy Rabbit ~10% energy Hawk ~1% energy ~90% heat ~90% heat ~90% heat The 10% Rule: only ~10% of energy transfers to the next level

Example 3: Volcanic Eruption

Scenario: A volcano erupts, releasing lava, ash, and gases. Trace how matter and energy move across Earth's systems.

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Geosphere: Magma (molten rock) rises to the surface, carrying thermal energy from deep within Earth.
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Atmosphere: \(\text{CO}_2\), \(\text{SO}_2\), and ash particles are released into the air. Matter transfers from geosphere to atmosphere.
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Hydrosphere: Ash settles into oceans and rivers. Volcanic gases dissolve in rainwater, forming acid rain.
4
Biosphere: Ash enriches soil with minerals, supporting new plant growth. Ecosystems recover over time.

Common Mistakes

✕ "Energy Is Recycled"
Energy flows one way: it enters from the Sun, transforms, and exits as heat. It is not reused like matter.
✕ "Matter Is Used Up"
Atoms are never destroyed. When wood burns, the carbon doesn't vanish: it becomes \(\text{CO}_2\) in the air.
✕ "Systems Are Separate"
Earth's spheres are deeply interconnected. A change in one (like burning fossil fuels) affects all others.

Summary: Earth System Interactions

Process Matter Movement Energy Change Spheres Involved
Photosynthesis \(\text{CO}_2 + \text{H}_2\text{O}\) into glucose Radiant into chemical Bio, Atmo, Hydro
Respiration Glucose into \(\text{CO}_2 + \text{H}_2\text{O}\) Chemical into thermal Bio, Atmo
Water Cycle \(\text{H}_2\text{O}\) changes state Thermal drives evaporation Hydro, Atmo, Geo
Combustion Fuels into \(\text{CO}_2\) + ash Chemical into thermal + light Geo, Atmo, Bio
Volcanism Magma, gases released Thermal from Earth's interior All four

Question 1 of 5

Which statement best describes the difference between matter and energy in Earth systems?

Question 2 of 5

During photosynthesis, a plant absorbs \(\text{CO}_2\) and water to produce glucose. What happens to the energy in this process?

Question 3 of 5

In a food chain, a grasshopper eats a plant and a frog eats the grasshopper. According to the 10% rule, if the plant stores 1000 units of energy, approximately how much energy is available to the frog?

Question 4 of 5

A volcano erupts, releasing \(\text{CO}_2\) and ash into the air. Which statement correctly describes this interaction between Earth's spheres?

Question 5 of 5

When wood burns in a campfire, producing \(\text{CO}_2\), water vapor, and ash, what happens to the matter?