OCEANOGRAPHY UNIT REVIEW By Mrs. Susan Dennison

What are oceans? Oceans are large bodies of salt water. Nearly 71% of Earth’s surface is covered with a continuous body of salt water.

How many oceans are there? Today, scientists name 5 oceans: Pacific (largest and deepest), Atlantic, Arctic, Indian, and Southern.

What are characteristics of oceans? Characteristics of oceans include: salinity, and extreme water pressure.

Where does the salt in ocean water come from? The salt in ocean water comes from minerals weathered in the Earth’s crust. It can be mined out of the Earth or taken from the sea.

What is desalination? Removal of salt from sea water is a process called desalination.

What is salinity? Salinity is the saltiness of the world’s oceans and seas. Sodium Chloride is the scientific name for the mineral salt.

What is water pressure? Water pressure is the weight of water pressing on an object. In the deepest part of the oceans, there is the most pressure.

What are features of the ocean floor? If you were to remove the water from the oceans, you would find that the floor has features similar to the continents: the continental shelf, continental slope, abyssal plains, ridges, volcanoes, and trenches.

How do ocean waters move? The waters of the ocean NEVER stop moving. This movement is due to waves. A wave is an up-and-down movement of surface water.

What are the parts of a wave? The highest point of a wave is called its crest. The lowest point is called its trough. Wave height is measured from trough to crest. Wave length is measured from crest to crest.

What produces waves? Wind produces most waves. The height of a wave is related to how hard the wind blows.

What else causes waves? Sometimes, waves can be caused by volcanoes and earthquakes. These giant waves are called tsunamis, or tidal waves.

Are there other kinds of waves? During hurricanes and tropical storms, large domes of water called storm surges form. When large storms waves join together, there may be a rogue wave, a huge wave much higher than the waves around it.

What moves most ocean water? Although waves are the most often seen kind of ocean movement, currents move much more water.

What is a current? A current is a stream of water that flows like a river through the ocean.

What causes ocean currents? Wind causes surface currents, which flow across the surface of the oceans. A famous surface current is the Gulf Stream. It can carry cold water to warm regions and warm water to cold regions.

What is a rip current? A rip current is a shoreline current that flows away from the beach. These can be dangerous for swimmers.

-Be cautious at all times, especially when swimming at unguarded beaches. If in doubt, don’t go out! -Whenever possible, swim at a lifeguard protected beach. -Obey all instructions and orders from lifeguards. -If caught in a rip current, remain calm to conserve energy and think clearly. -Don’t fight the current. Swim out of the current in a direction following the shoreline. When out of the current, swim towards shore. -If you are unable to swim out of the rip current, float or calmly tread water. When out of the current, swim towards shore. -If you are still unable to reach shore, draw attention to yourself: face the shore, wave your arms, and yell for help. -If you see someone in trouble, get help from a lifeguard. If a lifeguard is not available, have someone call Throw the rip current victim something that floats and yell instructions on how to escape. Remember, many people drown while trying to save someone else from a rip current.

What is a longshore current? Waves striking a shoreline at an angle move water forward along the shore.

What is a deep-ocean current? Differences in water temperature or salt content may cause a deep-ocean current. Cold water is heavier than warm water, so it sinks. The cold water then flows along the bottom of the ocean.

What is a tide? Once or twice a day, ocean water rises and falls at every beach around the world. This rise and fall in the level of the ocean is called a tide. These pictures show low and high tide at the Bay of Fundy in New Brunswick, Canada.

What causes tides? Tides are caused by the pull of gravity of the sun and moon on Earth’s waters. Since the moon is closer to Earth than the sun, it has a greater effect on tides than the sun does.

What is the shore? The area from where waves begin to break to the highest place they reach on the beach is called the shore. The shore is a place of constant change.

What is a tide pool? A tide pool is a pool of seawater found along a rocky shoreline. At high tide, the tide pool is under water and is a habitat for a great variety of plants and animals.

How do waves and currents change the shore? Ocean waves erode the shoreline. Ocean currents can also deposit beach materials along the coast, building new beaches.

What is a headland? A headland is a rocky point along a shore.

How do human activities affect the shore? People in coastal communities often build structures to protect their beaches from erosion.

How do humans explore the oceans? People have been exploring the oceans for thousands of years in various boats, large and small.

When did people first use diving suits? People designed diving suits as early as the 1400s, and were using Edmund Halley’s diving bell by 1690.

What is a submersible? A submersible is any underwater vehicle. Submersible vehicles increase our ability to investigate the deep oceans. Some are manned, and others are automated or remotely operated.

When did detailed studies of the oceans first begin? In 1872, the British ship, HMS Challenger, spent more than 3 years at sea. The crew took thousands of samples and measurements of the oceans. Their reports filled 50 books!

Who invented modern diving equipment? The Aqua-Lung, an early form of scuba equipment, was invented in 1942 by French explorer Jacques Cousteau.

What is SCUBA? Scuba is an acronym for self-contained underwater breathing apparatus. People take scuba class in a pool before they are certified to dive in the ocean.

How else do scientists explore oceans? Today’s scientists use many technologies to study oceans, such as satellites and sonar. Satellites study ocean currents from space and sonar uses sound waves to map the ocean floor.

Which is a better model for sonar, an echo or a mirror? An echo is a better model; it uses sound instead of light, and the surface it hits does not have to be smooth to reflect sound as a mirror does to reflect light. Sound waves bounce back.