The Ocean: A Unit Study

The Ocean: A Unit Study
The Ocean: A Unit Study

On January 23, 1960, the bathyscaphe Trieste made its famous descent into the depths of the Challenger Deep, the deepest known place in the ocean located in the Mariana Trench. The thus-far-unrepeated manned descent was carried out by Dr. Don Walsh, at the time a U.S. Navy Lieutenant, and the well-known oceanographer Jacques Piccard.

The Trieste

Designed by Jacques Piccard’s father, Auguste, the Trieste was first used to explore the Mediterranean Sea, until purchased by the U.S. Navy in 1958. After the purchase, the Trieste was used to explore the Mariana Trench, culminating in the record-breaking descent into the Challenger Deep.

The Ocean: A Unit Study

The dive was over 35,000 feet down under the ocean, withstanding a pressure of eight tons for every square inch! Obviously a special diving vessel was needed to survive such a voyage. For one thing, compressed air could not be used as it is on a submarine to drive water out of ballast tanks to lighten the ship for ascension.  The pressure was too great. The solution was to have a large, blimp-like structure above the pressure sphere where the passengers were seated.  The sphere was massive, having five-inch-thick walls, and obviously incapable of floating on its own. Hence, a supporting structure was needed.

To submerge the vessel, large amounts of iron were held in hoppers by electromagnets. When the magnets were de-energized, the weights would drop and the ship, now lighter than water, would slowly resurface.

The Ocean: A Unit Study

As the pressure was so massive, gasoline was used to float the Trieste. Gasoline had two needed characteristics: it is lighter than water, and it would not compress, and would therefore able to contain a vessel under crushing pressure. To illuminate the outside of the ship, quartz arc lamps were used, fused quartz being capable of withstanding high pressures.

For a window, several layers of strong Plexiglas were used. During the long descent, one of the outer windows broke, which jarred the entire ship. However the dive continued uninterrupted despite the nerve-racking episode with the window at over 30,000 feet under the sea, until the Trieste finally rested on the bottom.

The Ocean Floor

While at the bottom Piccard and Walsh reported seeing flatfish through the silt they stirred up.  Scientists speculate vertebrates cannot exist at such ocean depths due to the intense, bone-dissolving pressure.  Hence some marine experts doubt that Piccard and Walsh really saw any sort of fish, but suggest that perhaps they saw some type of sea cucumber.

The Ocean: A Unit Study

Unfortunately, Piccard and Walsh were unable to stay long.  The temperatures so far under the sea were near the freezing point, and inside their cabin it was only 45 degrees.  It had already taken them almost five hours to reach the bottom, and would take a little over three hours to resurface.

However, despite the short stay, the descent of the Trieste marked one of the monumental undertakings in the exploration of the ocean. The Trieste currently makes its home at the National Museum of the U.S. Navy, but barely any of it is original — even down to the pressure sphere!


Oceanography is, as its name implies, the study of the ocean and the things that dwell in it. Oceanography has prompted many manned and unmanned explorations of the depths of the ocean, where without proper equipment one would be crushed to nothing under the staggering pressure of the water above. Modern technology has greatly aided the exploration of the oceans.

One of the most interesting and beloved of all oceanography devices is the large drill that brings up long cylinders of the ocean floor. These cores reveal the massive variety of substances that make up the sea floor. Some other devices used to explore the ocean include probes that flow along with the current, current meters, thermometers for measuring the water temperature at various depths, and submersible robotic vehicles which can explore places where it is currently impracticable, if not impossible, to send humans.

The Amazing Ocean

The ocean is considered the earth’s last frontier, signifying how much of it is yet to be explored. The ocean makes up 71% of the earth’s surface and accounts for 97% of all the water on earth! The home of countless fish and other aquatic life, the ocean holds some of the world’s most varied and unique forms of life, sunken ships still more or less preserved under many feet of salt water, colorful coral reefs, and vast quantities of secrets yet withheld.

Further Investigation

To the Depths in the Trieste
Account of the voyage from the University of Delaware.

Trieste Bathyscaphe
Extensive account of the dive hosted at Bluebird Marine Systems.

Background on the ship from the Department of the Navy.

Research Vessels: Submersibles – Trieste
Press releases on the dive.

The Mariana Trench
Facts, figures, and graphics to help understand the deepest place in the ocean, including the role the Trieste played.

The Mariana Trench: Oceanography
Facts about the deepest place in the ocean.

Physical Ocean
NASA page exploring the ocean surface topography, temperature, winds, salinity, currents, and ice.

Ocean in Motion
Explains currents, tides, and waves.  Use the navigation bar on the left to also explore ocean habitats, life, water characteristics, regions, and research vessels. From the Office of Naval Research.

Earth’s Oceans: An Introduction
Simple information for younger students from Enchanted Learning.


Oceanography Merit Badge Workbook
Free 11-page download for Boy Scout Merit Badge, but works well as a guide to studying oceanography.

Multimedia Discovery Missions
14 different high-quality interactive missions from NOAA exploring the ocean with video presentation and correlated activities covering plate tectonics, ridges, corals, currents, waves, water cycle, and more.

Don’t Get Tide Up
Learn how to read a tidal chart and get the boat under the bridge.

Coral Reef Virtual Tour
Virtual tour of the coral reefs.

Great Barrier Reef
Virtual tour.

Deep Sea Strangers
Explores the creatures of the deep.

Label the Earth’s Oceans
Activity from Enchanted Learning.

The Ocean Book

The Ocean Book by Frank Sherwin
Covering deep-ocean research, the different physical characteristics of the ocean, icebergs, tides, waves, currents, how weather affects the ocean, ocean resources, marine life, the coral reef, various ocean-exploring vehicles and the Great Flood. A free study guide is also available.

Introduction to Physical Oceanography
Free PDF textbook written to college students, but very accessible.

Jules Verne: A Unit Study

Twenty Thousand Leagues Under the Sea by Jules Verne
A fun fictional go-along in the public domain.  Also available in PDF form.

Glimpses of Ocean Life {Free eBook}
Wonderful introduction to marine biology.

Unit Studies & Lesson Plans

Ocean Explorer
Lesson plans from NOAA exploring the various parts of the ocean.

Seasonality in the Ocean
Lesson plan comparing the seasons on land with those in the ocean.

Water, Water Everywhere
Extensive Core Knowledge lesson plan covering islands, oceans, currents, tides, saltwater, waves, and ocean life in seven lessons with culminating project.

Printables & Notebooking Pages

Mariana Trench Graphic
Great printable for notebook illustrating the depth.

The Ocean Notebooking Pages
Simple pages for copywork, narrations, or wrapping up.