The water cycle

Evaporation

The process of a liquid changing into a gas due to an increase in temperature or pressure.

Condensation

The process of a gas changing into a liquid due to a decrease in temperature or pressure.

Precipitation

Condensed water vapor that falls back to Earth, such as snow, rain, sleet, or hail.

Transpiration

The process by which plants absorb water through their roots and give off water vapor through their leaves.

Surface runoff

Precipitation that reaches Earth's surface, flows over land, and reaches lakes, rivers, and oceans.

Ground water

Water that lies beneath the ground.

Atmosphere

A thin blanket of gases that surrounds the Earth, held in place by gravity, which protects life from radiation from the Sun.

Biosphere

The place where life exists in all forms, including plants and animals.

Geosphere

The solid Earth made of rocks, soil, and minerals; includes the crust, mantle, and core.

Hydrosphere

Water that exists on the surface of Earth, such as lakes, glaciers, water vapor in air, and ground water.

Water vapor

Water in the form of a gas.

Crystallization

The process when a liquid turns into a crystalline solid.

Reservoirs

Storage areas for water, including oceans, lakes, glaciers, ice caps, or ground water.

Water cycle

The continuous movement of water from Earth's surface to the atmosphere and back again.

Glaciers

Large masses of ice that move slowly over land.

Ice sheets

Glaciers that spread out over land in all directions; made from layers of snow that compact over time.

Clouds

Collections of water droplets, ice crystals, and dust particles in the atmosphere.

Infiltration

The process where water soaks into the soil and moves into rocks through cracks and pores.

Sublimation

The process of snow and ice changing directly into water vapor without first melting.

Atmospheric pressure

The weight of air molecules pushing on everything.

Greenhouse effect

The process by which sunlight warms the Earth and some heat is trapped by gases in the atmosphere.

Contrails

Water vapor that condenses and freezes from an aircraft's fuel combustion, forming trails in the sky.

Cumulus clouds

White, puffy clouds with flat bottoms that indicate fair weather but can produce thunderstorms when they grow larger.

Stratus clouds

Clouds that form in layers and cover large areas of the sky, blocking out the sun.

Cirrus clouds

Thin, feathery, wispy clouds made up of ice crystals.

Nimbostratus clouds

Dark clouds that produce continuous rain.

Cumulonimbus clouds

Clouds that appear as tall towers and produce thunderstorms.

'Alto' clouds

Middle elevation clouds made of water droplets and ice crystals.

'Cirro' clouds

High clouds made up of ice crystals.

'Low' clouds

Clouds made of water droplets that form below 6500 feet.

Fog

Clouds that form close to the ground.

Aquifers

Areas of permeable sediment or rock holding significant amounts of water.

Biodiversity

The variety and abundance of different types of plant and animal species within a particular region.

The two things that drive the movement of the water cycle

The Sun and Gravity.

Where is groundwater stored?

In cracks and pores beneath Earth's surface.

How does the energy from the Sun cause evaporation?

It breaks the bonds between water molecules.

The four main subsystems of Earth

Atmosphere, Hydrosphere, Geosphere, Biosphere.

The three states of water in Earth's systems

Liquid (water), ice (solid), water vapor (gas).

What happens to the temperature at higher altitudes?

It decreases.

What percentage of Earth's freshwater is frozen in ice caps and glaciers?

About 70%.

Where have glaciers existed or currently exist?

Bering glaciers in Alaska, Kutiah glacier in Pakistan, Yosemite Valley in California, and The Great Lakes.