Essentials of Oceanography

Seawater Properties I; Activity 1


Activity 1: Science Fiction Blog: if the properties of water were different


Write a 500-word blog (could be longer if you think you need the space, but...) to help demonstrate understanding about the properties of water. This one will be a "science fiction" piece, envisaging how the oceans might be different if some fundamental property of water were very different from reality (e.g., what if viscosity were a lot higher or heat capacity a lot lower, or...?). Get creative.

  1. Submit your blog to the group for comment via Canvas: Lesson 3, Activity 1: Science Fiction Blog: If Water Behaved Differently.
  2. Reply briefly to 2-3 posts.

We can see this being a useful way to engage your students in thinking "outside the box" about the importance of water properties to the nature of the ocean and the continuity of life, and to give them an opportunity for creativity--not just reiterating what they read in textbooks. But we will leave that evaluation up to you after you have tried this exercise. The original course authors wrote an example below--a bit different vein, but a similar principle. This is called "Earth without Oceans." Earlier you read some speculation about what should happen if water ice (solid) were denser than liquid water, like most substances. Wow, what a difference!

Sample Blog from Mike and Chris:

Ask yourself this question before reading the speculation below. See if you can come up with other differences between the Earth with and without an ocean. The bottom line is that the Earth would be very much different than it is today.

Critical Assumptions: the answer would differ depending on: 1) whether oceans were created and then later destroyed (after evolution of life) or, 2) never existed on Earth at all. A secondary consideration would be the nature and composition of the atmosphere with or without an ocean.

Water is probably Earth's most important resource. Without water, perhaps only the simplest viruses could exist. Yes, the Earth would be there still, but life on it would have to adapt to very different conditions. In fact, life as we know it may not have evolved on earth without the oceans.

We must assume that the earth retained some atmosphere (mostly inert gases and carbon dioxide). Without oceans, the earth's surface would be a dusty desert, typified by wild daily and yearly swings in temperature. The hydrologic cycle could not really function without some perennial bodies of water. Having no water cycle would mean no rain. Without rain (and plants--see below), the Earth's surface would weather much more slowly and surface topography and rock type would be much different.

Earth surface temperatures would vary dramatically from equator to pole because energy from the sun would be distributed unequally on the earth. Solar energy would normally evaporate water from the oceans in the tropical regions and transport this vapor and its contained energy from low to high latitudes in the atmosphere; the ocean would normally transport heat energy to the polar regions as well. Without the oceans, therefore, there would be no efficient mechanism for redistributing heat.

Life, as we understand it, would have a hard time evolving or prospering without oceans. All extant plants and animals would die if the oceans were suddenly removed from the Earth, although certain bacteria and very simple organisms might survive. With no oceans, the oceanic phytoplankton and the land plants that provide our oxygen through photosynthesis would be eliminated. Normally respiring organisms would suffocate as the result of the lack of oxygen, the amount of carbon dioxide would increase in the atmosphere, and the Earth's temperatures in the lower latitudes might increase dramatically, probably enough to drive any other surviving animals or plants to extinction.

Hey, maybe this is what happened on Mars!?

Submitting your work

  • You can begin the discussion on Canvas. To respond to another student's posting, use the "reply" link that follows their posting.

Grading criteria

See the grading rubric for specifics on how this assignment will be graded.