Unit 1 Vocabulary: Water in Earth's Systems

A comprehensive set of vocabulary flashcards based on the Unit 1 study list for Water in Earth's Systems.

Fresh water

Water that has very little dissolved salt in it. Only about 3% of Earth's water is fresh water, and most of it is frozen.

Salt water

Water that has a large amount of dissolved salt in it. About 97% of Earth's water is salt water.

Oceans

Large bodies of salt water that cover about 71% of Earth's surface and hold about 97% of all the water on Earth.

Glaciers

Huge masses of ice on land that move very slowly. Glaciers and ice caps hold the largest amount of Earth's fresh water.

Groundwater

Fresh water stored underground in the cracks and spaces between particles of soil, sand, and rock. It is not an underground lake.

Aquifers

Underground layers of rock or sediment that hold groundwater and let it flow through. Many communities pump drinking water from aquifers.

Lakes

Large bodies of standing fresh water surrounded by land.

Rivers

Bodies of fresh water that flow downhill through a channel toward a lake or the ocean.

Swamps

Wetlands where the ground stays soaked with shallow fresh water and trees and shrubs grow.

Water cycle

The continuous movement of water between Earth's surface and the atmosphere. It is powered by energy from the sun and the force of gravity.

Evaporation

The change of liquid water into water vapor when the sun's energy heats it. This moves water from the surface into the air.

Transpiration

The release of water vapor into the air through the leaves of plants.

Precipitation

Water that falls from clouds back to Earth's surface as rain, snow, sleet, or hail.

Runoff

Water that flows across the surface of the land instead of soaking in. Gravity pulls it downhill toward streams, rivers, and the ocean.

Infiltration

The process of water soaking down into the ground through soil and rock. Infiltration is how groundwater is refilled.

Continental shelf

The shallow, gently sloping edge of a continent that is covered by ocean water. It starts at the shoreline.

Continental slope

The steep drop off at the outer edge of the continental shelf that leads down toward the deep ocean.

Continental rise

The gentle slope of piled up sediment at the bottom of the continental slope. It connects the slope to the deep ocean floor.

Deep ocean floor

The wide, flat region beyond the continental margin, also called the abyssal plain. It is the flattest part of Earth's surface and is covered in sediment.

Mid ocean ridge

A chain of underwater mountains that forms where tectonic plates pull apart and new ocean floor is created.

Oceanic trench

A long, narrow, extremely deep valley in the ocean floor that forms where one plate sinks beneath another. Trenches are the deepest places in the ocean.

Seamount

An underwater mountain, usually an old volcano, that rises from the ocean floor but does not break the surface of the water.

Surface zone

The top layer of the ocean that sunlight reaches. It is the warmest layer, and most ocean plants and animals live here because photosynthesis can happen.

Twilight zone

The middle layer of the ocean below the surface zone. Only dim light reaches it, so it is colder, darker, and plants cannot make food here.

Salinity

A measure of how much dissolved salt is in the water. The average salinity of ocean water is about 35 parts per thousand.

Waves

The movement of energy through water. Wind is the usual source of that energy. The energy moves forward while the water mostly moves up and down.

Crest

The highest point of a wave.

Trough

The lowest point of a wave.

Wavelength

The horizontal distance from one crest to the next crest, or from one trough to the next trough.

Wave height

The vertical distance from the trough of a wave to its crest.

Breaker

A wave that tips over and collapses as it moves into shallow water near the shore.

Surface current

The movement of ocean water at or near the surface, driven mainly by steady winds. Surface currents move warm and cold water around the globe.

Density current

The movement of ocean water caused by differences in density. Cold, salty water is denser, so it sinks and flows beneath warmer, less salty water.

Coriolis Effect

The curving of moving air and water caused by Earth's rotation. Currents curve to the right in the Northern Hemisphere and to the left in the Southern Hemisphere.

Tide

The daily rise and fall of ocean water, caused mainly by the gravitational pull of the moon and, to a lesser degree, the sun.

Conduction

The transfer of thermal energy between objects or particles that are touching.

Convection

The transfer of thermal energy by the movement of a fluid such as water or air. Warm fluid rises and cool fluid sinks, creating a convection current.

Radiation

The transfer of energy by electromagnetic waves. Radiation does not need matter to travel through, which is how the sun's energy reaches Earth.