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Water in Earth’s Processes Study Guide

Our test will be on ______.

Distribution

70% of the Earth’s surface is covered by water.

97% of the water on Earth is salt water.

  • The salt in the ocean and seas comes from weathering and erosion of rocks.
  • Sea water has a higher concentration of sodium chloride, NaCl.
  • When fresh water pours into the ocean, the salinity (salt content) stays the same because water continually evaporates out of the ocean.

3% of the water on Earth is fresh water.

  • Ice caps and glaciers make up 2%. (The greatest amount of fresh water on Earth is found in glaciers and polar ice caps.)
  • Groundwater makes up .9%.
  • Rivers, lakes, and swamps make up .1%.
  • If new wells are created due to a population increase, the water table would drop.

Water Cycle

The water cycle is powered by heat from the Sun. It is the continuous movement of water from the ocean to the atmosphere to the land and back to the ocean.

  • Evaporation is when liquid water changes into water vapor and rises. Transpiration is evaporation of water through plant leaves. (If you were to hang a wet swimsuit to dry, the heat of the sun, the speed of the wind, and the amount of water vapor in the air (humidity) would affect the evaporation/dry time.
  • Condensation is when water vapor cools and changes into water droplets that form clouds in the atmosphere.
  • Precipitation is rain, snow, sleet, or hail that falls from clouds onto the Earth’s land and oceans.
  • Percolation is the downward movement of water through pores and other spaces in soil due to gravity.
  • Runoff is precipitation that flows over land into streams and rivers.
  • Accumulation is when water gathers in large quantities such as rivers, lakes, oceans, glaciers, ice caps, and aquifers (geological formation containing groundwater.)

Waves

Waves are mostly caused by wind, which is caused by energy from the Sun. Sometimes undersea earthquakes or landslides can cause waves.

Currents

A current is a movement of ocean water that forms a regular pattern.

Surface ocean currents are caused by global winds, the Coriolis Effect, and continental deflections.

Density differences due to salinity create deep currents but not ocean waves.

Tides

Tides are the daily rise and fall of water levels that are caused by gravity due to the moon and sun. Water rises slowly and covers the shore twice a day then slowly falls back.

High spring tides are caused by an alignment of the Earth, moon, and sun.

Neap tides have the smallest daily tidal change and occur when the sun and moon are at right angles relative to the Earth. The gravitational forces of the sun and moon work against each other.

Ocean Topography

Draw and label the parts of the ocean floor.

Sonar is used to measure the depth of the ocean floor.

As you go deeper into the ocean, the pressure increases; therefore, the pressure would be the greatest in a trench.

Algae is found above the continental shelf since it needs sunlight to survive.

Mid-ocean ridges are underwater mountain chains near active volcanoes.

Resources and Energy

Recycling – reusing waste or scrap materials to help people save natural resources.

One renewable resource from the ocean is wave energy.

Hydroelectric energy is energy created by the movement of falling water.