Essentials of Oceanography

Lesson 3 Introduction


About Lesson 3

In this lesson, we will return to the amazing properties of water and how those properties influence Earth surface processes. We will explore the structure of water molecules and of water itself (yes, water has "structure"), and relate these concepts to important processes, such as the buffering of Earth surface temperature variations and weathering (breakdown) of rocks on land. In addition, we will investigate the composition of sea salt and its origin, as well as some of the exchanges of salt and water between various reservoirs (storage bins) at the Earth's surface. Although based on chemistry (scary or "boring" to some students), this topic has some fascinating elements that can really engage students, including thinking about the importance of salt in human history, debates about the age of the Earth from an ocean perspective, and the potential for extracting metallic riches from the ocean. The topical coverage for Lesson 3 is as follows:

  • Ice, water and vapor
  • Latent heat, heat capacity, and other unusual properties
  • Water as the universal solvent
  • Why the sea is bitter
  • It’s all about cycles: from vapor to rain to snow to rivers and the ocean (the "Hydrologic Cycle").
  • Geochemical residence time
  • Salt as a commodity and the age of the oceans

What will we learn in Lesson 3?

By the end of Lesson 3, you should be able to:

  • List the important characteristics of ice, water and vapor, and cite why they are important
  • Describe latent heat and heat capacity and apply concepts to understanding climate processes
  • Explain why water is the universal solvent
  • Speak knowledgeably about the origin of salts in seawater
  • List the factors that determine seawater salinity and the elemental composition of seawater salt
  • Explain the hydrologic cycle and its linkages to water properties
  • Explain the concept geochemical residence time in the oceans and what insights it provides.

What is due for Lesson 3?

The table below provides an overview of the requirements for Lesson 3. For details, please see the Course Schedule.

Lesson 3 Assignments
Activity 1: Science Fiction Blog: If Water Behaved Differently page 8 Yes - Your discussion participation counts toward your overall class participation grade. This discussion will take place on Canvas.
Activity 2: The Residence Time of Salt in the Ocean page 9 Yes - Your discussion participation counts toward your overall class participation grade. This discussion will take place on Canvas.
Activity 3: End of Unit Quiz (Canvas) Canvas Yes. We will activate a set of questions to "test" your understanding of the material a few days before the end of this lesson. The exam should take no more than one hour, but you are welcome to start it and then complete it later. The exam is 'open book.' Feel free to use any resources.


If you have any questions, please post them to our Questions link on Canvas. I will check that discussion forum daily to respond. While you are there, feel free to post your own responses if you, too, are able to help out a classmate.