__________ is the force that pulls molecules on the surface of a liquid together to form a layer.

A substance's ability to absorb heat energy is called its _________.

Forming hydrogen bonds between water molecules releases energy (heat).

Water is more dense as a liquid than a solid.

Transpiration represents about _______ of the way water in the atmosphere enters the water cycle.

Evaporation requires a lot of heat and condensation releases a lot of heat.

Evaporation is a crucial process of the water cycle because it creates clouds.

The relationship between the input and the output of all the water on Earth is called the ___________________.

Today, glaciers exist on every continent.

Snow that partially melts, compacts, and recrystallizes forms a grainy ice called _____________.

Near the foot of the glacier in a region called the _______________, glacial ice reduces by melting, evaporating, or calving.

The accumulation zone is separated from the ablation zone by the equilibrium line.

The process of __________ involves portions of a glacier breaking off to create more glaciers.

Today continental glaciers cover about _________ of the earth's land mass.

Continental glaciers are much larger than valley glaciers and are also known as alpine glaciers.

As water emerges from underground, it produces a small stream known as a spring.

_________ of the earth's freshwater supply is locked up in the ground.

The path a stream follows is a called a ____________.

A stream or river that flow into a larger stream or river is a _____________.

The largest watershed in the U.S. is the Mississippi River Basin, which covers more than __________ of the U.S.

A fast-flowing, irregular river with a steep V-shaped channel.

Water that flows over rocks that are not easily weathered does not pick up many, if any, dissolved minerals. This water is called ______________________.

Mature rivers are fed by many tributaries, which allows them to carry more water than youthful rivers.

Old rivers have even more tributaries than mature rivers.

A meandering river located at a low elevation.

The Tigris and the Euphrates are examples of old rivers located in the Middle East.

A slow-moving, flat river

The four habitats in ponds and lakes are: the shore, surface film, open water, bottom water.

Algae, flagellates, plants, invertebrates, __________, and fish are examples of the producers, consumers, and decomposers in the ecosystem of ponds and lakes.

A river with an increased stream gradient and power to erode.

Thermal stratification is when the water's density changes with the temperature.

A summer's heat warms a lake from the surface down, three layers of water form and are called epilimnion, ____________, and hypolimnion.

Warm water is more dense than cold water.

Mature rivers bend to form wide curves. Some of these curves may become cut off from the main river to form lakes or ponds called _________________.

Runoff or stream water that flows over soft rock like limestone may become what is called _____________.

Hard water is measured by the amount of calcium carbonate found in a water sample.

Ponds generally have a long lifespan and develop into marshes and then meadows.

During the day water plants and algae capture sunlight for ________________.

The _____________ make up the world's largest surface area of freshwater.

A ___________ is a permanent structure built across a river to regulate water flow.

Hydroelectric power supplies nearly ________ of the world's electric power.

Hydroelectric power is the least used renewable resource in the world.

Nitrogen and calcium are the two most common minerals required by plants, so most fertilizers contain these two minerals.

The process of eutrophication begins with algal bloom, which is an explosive growth of algae cause by too many nutrients in the water.

Brown tides are created by increased dinoflagellate populations.

A common example of algal bloom that occurs along the coast is called red tide.

Scientists estimate that the human impact on nature is about _________ times higher today than it was 40-50 years ago.

In the late 1960's which of the Great Lakes was declared a dead zone?

When populations of Aureococcus anophagefferens, a type of algae, grow in areas of low sunlight and high concentrations of nitrogen and phosphorus they form __________________________.

The force of attraction between different molecules is called _________________.

What is the main way water enters the atmosphere?

The continuous cycle that stores water and moves it from the atmosphere to the earth's surface and back to the atmosphere is called the water cycle or ______________ cycle.

An area that has been depleted of oxygen by eutrophication.

The process by which nitrate or phosphate compounds overenrich a body of water and deplete it of oxygen.

The changing of a substance from a gas to a liquid.

The loss of water by plants.

The underground region where pore spaces are saturated with groundwater.

An explosive growth of algae caused by too many nutrients in the water.

A permeable underground layer of rock.

The process that converts solids directly into gases without first becoming a liquid.

The underground region where pore spaces contain air and water.

All the water found underground.

A ridge or other elevated region that separates watersheds.

A structure built to prevent a river from overflowing

The electricity produced from the power of moving water.

A natural or artificial lake used to store and regulate water.

A large percentage of water evaporates from the ocean and travels through the water cycle to be delivered on land through precipitation.

Local water budgets are usually balanced.

Water has a higher rate of permeability through gravel than through clay.

Lakes are always deeper than ponds.

Hard water contains dissolved minerals such as calcium and magnesium.

Saltwater makes up how much of the Earth's water supply?

Where is most of Earth’s water located?

Water can exist on Earth as...

Freshwater makes up how much of the Earth's water supply?

Salinity is the amount of salt in a body of water.

Most of the Earth's fresh water exists in

What has to happen to water for it to evaporate?

What has to happen to water for it to condense?

Which term includes rain, hail, snow and sleet?