AQA A-level Water & Carbon Cycle Knowledge Booklet
Natural Systems
Components of a System
Inputs: matter/energy entering the system eg. precipitation
Outputs: matter/energy exiting the system eg. water vapour
Stores: elements of the system that hold matter/energy eg. trees
Flows/Transfers: movement within the system eg. throughflow
Processes: actions that occur within the system eg. photosynthesis
Energy: a power or force within a system eg. solar radiation
Matter: substances that have weight and require space eg. water
Types of Systems
pen systems- systems with external inputs and outputsof energy and matter exchange
O
Closed systems- systems that have external inputsand outputs of energy but no matter
exchange (matter doesn’t move in or out of the system boundaries)
Earth’s Global Systems
.
1 tmospheric system: the gas interactions
A
2. Hydrosphere system: the water interactions
3. Biosphere system: the biological life interactions
4. Lithosphere system: the planet’s crust interactions
5. (Cryosphere system: the ice’s interactions)
6. (Pedosphere system: the soil’s interactions)
F eedback Systems and Equilibrium
Dynamic equilibrium is the state of balance that maintains systems through equal inputs and outputs
When equilibrium is lost feedback loops oppose or exacerbate the change…
1. Negative feedback loops (opposing)
- These help restore equilibrium and promote stability by counteracting any changes
in the system
2. Positive feedback loops (exacerbating)
- These amplify changes in the system creating a bigger change
, The Water Cycle
Global Distribution
Key Stores
cean - Largest store of water → Largest source of evaporation for atmospheric moisture
O
Atmoshpere - Carries water via clouds
Key Processes
1. Evapotranspiration
- Transpiration happens in plants when they respire; during this they release water
through their leaves which is then evaporated
2. Condensation
- The process where water vapor becomes liquid
3. Precipitation
- Convectional-caused rain: air rises whenheated bythe sunand falls as rain after
condensation
- Relief-caused rain: warm air is forced upwards by barriers such as mountains and
falls as rain after condensation
- Frontal-caused rain: when there is two temperatures of air the warm naturally goes
higher above the cool air and falls as rain when it condenses
Essentially all precipitation occurs following condensation but the reasons why the air
rises are different
0% of Asia’s rice paddiesrely on rainfall from monsoonseason - theres a15% decrease in
6
yieldsin weak monsoon seasons
50% of population rely on groundwaterwhich is primarilyreplenished by precipitation
4. Cloud formation
a. The sun's heat warms the ground
b. Warm air rises carrying (evaporated) water vapour within it
c. Once it gets to a high altitude it cools and the water vapour condenses around
condensation nuclei
d. When enough water vapour condenses on the nuclei a water droplet forms
e. Water droplets form a floating cloud
f. When they combine they become too heavy to float and fall as precipitation
The Hillslope
Key flows:
1. Surface Runoff - the movement of water above surface
2. Infiltration - the movement of water from surface to soil
Natural Systems
Components of a System
Inputs: matter/energy entering the system eg. precipitation
Outputs: matter/energy exiting the system eg. water vapour
Stores: elements of the system that hold matter/energy eg. trees
Flows/Transfers: movement within the system eg. throughflow
Processes: actions that occur within the system eg. photosynthesis
Energy: a power or force within a system eg. solar radiation
Matter: substances that have weight and require space eg. water
Types of Systems
pen systems- systems with external inputs and outputsof energy and matter exchange
O
Closed systems- systems that have external inputsand outputs of energy but no matter
exchange (matter doesn’t move in or out of the system boundaries)
Earth’s Global Systems
.
1 tmospheric system: the gas interactions
A
2. Hydrosphere system: the water interactions
3. Biosphere system: the biological life interactions
4. Lithosphere system: the planet’s crust interactions
5. (Cryosphere system: the ice’s interactions)
6. (Pedosphere system: the soil’s interactions)
F eedback Systems and Equilibrium
Dynamic equilibrium is the state of balance that maintains systems through equal inputs and outputs
When equilibrium is lost feedback loops oppose or exacerbate the change…
1. Negative feedback loops (opposing)
- These help restore equilibrium and promote stability by counteracting any changes
in the system
2. Positive feedback loops (exacerbating)
- These amplify changes in the system creating a bigger change
, The Water Cycle
Global Distribution
Key Stores
cean - Largest store of water → Largest source of evaporation for atmospheric moisture
O
Atmoshpere - Carries water via clouds
Key Processes
1. Evapotranspiration
- Transpiration happens in plants when they respire; during this they release water
through their leaves which is then evaporated
2. Condensation
- The process where water vapor becomes liquid
3. Precipitation
- Convectional-caused rain: air rises whenheated bythe sunand falls as rain after
condensation
- Relief-caused rain: warm air is forced upwards by barriers such as mountains and
falls as rain after condensation
- Frontal-caused rain: when there is two temperatures of air the warm naturally goes
higher above the cool air and falls as rain when it condenses
Essentially all precipitation occurs following condensation but the reasons why the air
rises are different
0% of Asia’s rice paddiesrely on rainfall from monsoonseason - theres a15% decrease in
6
yieldsin weak monsoon seasons
50% of population rely on groundwaterwhich is primarilyreplenished by precipitation
4. Cloud formation
a. The sun's heat warms the ground
b. Warm air rises carrying (evaporated) water vapour within it
c. Once it gets to a high altitude it cools and the water vapour condenses around
condensation nuclei
d. When enough water vapour condenses on the nuclei a water droplet forms
e. Water droplets form a floating cloud
f. When they combine they become too heavy to float and fall as precipitation
The Hillslope
Key flows:
1. Surface Runoff - the movement of water above surface
2. Infiltration - the movement of water from surface to soil
