Earth's Spheres
The Water Cycle
The Rock Cycle
The Carbon Cycle
The Nitrogen Cycle
100

This sphere contains all of the liquid water on Earth.

What is the hydrosphere?

100

This stage describes when water droplets begin to come together.

What is condensation?

100

These rocks are formed from intense heat and pressure.

What are metamorphic rocks?

100

Plants use CO2 for this process.

What is photosynthesis?

100

Nitrogen exists in this form in the atmosphere.

What is N2?

200

This sphere contains all of the living organisms on Earth.

What is the biosphere?

200

This provides all of the energy to begin the Water Cycle.

What is the Sun?

200
These rocks are formed when molten rock solidifies.

What are igneous rocks?

200

This is the form carbon exists as within the atmosphere.

What is Carbon Dioxide (CO2)?

200

These organisms break down complex nitrogen compounds, returning them to the soil.

What are decomposers?

300

This sphere contains all of the frozen water on Earth.

What is the cryosphere?

300

This drives the following stages of the Water Cycle: precipitation, surface runoff, and infiltration.

What is gravity?

300

These rocks are formed by compaction and cementation.

What are sedimentary rocks?

300

Animals, such as ourselves, return carbon in this form to the atmosphere.

What is Carbon Dioxide (CO2)?

300

This step describes the process by which organisms take in nitrogen in usable forms.

What is assimilation?

400

This percentage is the amount of salt water on Earth.

What is 97.5%?

400

This stage describes the movement of water along the top of the ground due to gravity.

What is surface runoff?

400

These are the only rocks to contain fossils.

What are sedimentary rocks?

400

Carbon dioxide can diffuse into this from the atmosphere.

What is the ocean?

400

This step describes when bacteria convert Nitrogen Gas (N2) into organic compounds.

What is Nitrogen Fixation?

500

This percentage is the amount of water usable by humans.

What is <1%?

500

This stage occurs when water leaves the pours on the leaves of plants.

What is transpiration?
500

These rocks often contain bands and crystals.

What are metamorphic rocks?

500

The burning of these contributes heavily to global warming.

What are fossil fuels?

500

This step describes when soil bacteria convert nitrate ions (NO3-) into Nitrogen gas (N2).

What is denitrification?

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