Water on EarthChapter 7

Vocabulary

The vocabulary for chapter 7 has already been placed on Edmodo. Remember that studying in advance for an assessment is important.

Chapter Vocabulary: salinity, aquifer, water table, reservoir, condensation, evaporation, precipitation, sublimation, sleet

Term Prediction Definition

Salinity

Aquifer

Water Table

Reservoir

Sleet

How can the oceans be described?

Unlike other planets, Earth has a huge amount of water. This water covers most of the surface of the planet. Most of Earth’s water is in the salty oceans.

What body of water is closest to where you live?

More than half the people in the United States live within about 80 kilometers of an ocean.

Bodies of water play a huge role in our lives.

They give us a way to travel, place to catch food, and beautiful sights to visit.

The Hydrosphere

All the waters of Earth form the hydrosphere.

The hydrosphere covers about three-fourths of the Earth’s surface.

Salinity

Have you ever been swimming in the ocean and happened to get a mouthful of some seawater?

Ocean water is salty. Salinity is a measure of the salt concentration in water.

The temperature of ocean water varies and is influenced by distance from the equator.

The ocean is a source of fish, salt, and other resources.

Salinity

The Oceans get their salt from rivers.

Rivers dissolve small amounts of salt from rocks and soil and carry the slats to the ocean.

Most of this salt is sodium chloride-common table salt.

When water evaporates from the ocean, the dissolved salts are left behind in the ocean water.

Salinity Continued

Salinity-Measure of how salty water is.

Ocean water is more salty in some places than in other places.

For example-Places where rivers pour fresh water into the ocean have low salinity. In warm areas, ocean water evaporates fairly quickly. Salt is left behind and the ocean water has higher salinity.

Ocean Currents

A liter of cold water with high salinity is heavier than a liter of water that is either warmer or has a lower salinity.

Some currents in the ocean are caused by cold salty water sinking under warmer water.

Most ocean currents on the ocean’s surface are caused by winds.

Salinity-Ocean Currents

Ocean Temperatures

The temperature of ocean water varies from place to place. Ocean water near the equator can be about 30 degrees Celsius.

Near the poles, ocean water can be as cold as -2 degrees Celsius.

Ocean Temperatures

The water is not always colder just because it is farther north. Some currents carry warm water towards the poles. The Gulf Stream is such a current. It moves warm water from the Caribbean Sea to the North Atlantic Ocean.

Other currents carry cold water toward the equator.

For Example- The California Current carries cold water southward along the coast of the United States.

Ocean Resources

Must of the salt we add to our foods comes from the ocean.

One way that people get salt is by evaporating ocean water. People who process alt allow ocean water to flow into shallow ponds. The water evaporates and the salt is left.

Ocean Resources

Other Materials: Magnesium and drinking water, also come from ocean water.

Made drinkable by removing the salt. This is expensive, so it is not done in many places.

Food=Do you like Tuna?

Review Questions

How would a mouthful of ocean water taste?

Salty

A company is deciding whether to set up an outdoor salt processing plant in southern Florida or northern Maine. Which would process salt faster? Why?

Southern Florida, due to the fact the climate is warmer in Southern Florida, so evaporation is faster.

Why does cold water sink under warm water in the ocean?

Cold water is heavier than an equal volume of warm water.