Common Misconceptions About Oceans

Oceans are mysterious places. Our experience with them is often limited to visits to the beach or the aquarium and to books, television shows, and movies. As a result, we sometimes know a bit about marine animals, waves, and tides, but less about currents and the oceans’ role in driving our earth’s climate. Our understanding is often incomplete or full of misconceptions.

Ongoing work by the Ocean Literacy Network defines seven essential principles of ocean literacy:

  1. Earth has one big ocean with many features.
  2. The ocean and life in the ocean shape the features of Earth.
  3. The ocean is a major influence on weather and climate.
  4. The ocean makes Earth habitable.
  5. The ocean supports a great diversity of life and ecosystems.
  6. The oceans and humans are inextricably linked.
  7. The ocean is largely unexplored.

While these principles certainly represent important concepts, not all of them are fully accessible to elementary students. The Ocean Literacy Network’s web site also makes available concept flow diagrams that may be helpful for K-12 teachers planning an ocean unit.

A professor of oceanography documented 110 misconceptions about the oceans held by his students who were not science majors. In this article, we’ve focused on a smaller number of misconceptions that might be held by elementary students. In addition, we’ve included ideas for formative assessment and suggestions for teaching correct scientific concepts and principles.


Ocean Characteristics

Students may think… Instead of thinking…
Oceans are shaped like a bowl. While the continental shelf and continental slope may remind students of a bowl, the ocean floor is not flat, nor is it uniform. Canyons, mountains, and plains are all found on the sea floor.
Oceans are deepest in the middle. Many of the oceans’ deepest points are trenches, deep canyons that are formed at plate boundaries. These are not in the middle of oceans.
The sea floor is flat. The sea floor has canyons, mountains and mountain ranges, and plains just as the land does. Many of these features are much larger than those found on land.
The bottom of the ocean is a big, sandy desert. The ocean floor is rocky and uneven.
Coasts and coastlines do not change. Coasts and coastlines change as a result of erosion. Sea-level rise may also affect them.
The ocean is blue because it reflects the color of the sky. Sunlight is made up of all colors of the rainbow. When sunlight hits the ocean it is scattered by the water molecules. Blue light is scattered the most – which is why the ocean looks blue. However, floating plants, sediments, and algae may make the ocean appear to be green, yellow, or even red!

Sea Water

Students may think…

Instead of thinking…

Table salt + water = sea water Sea water’s “salt” is made of dissolved minerals from surface runoff (excess water from rain, snow or other sources that must flow over land).
Oceans have the same salinity everywhere. Salinity can vary by location or season. In the Arctic and Southern Oceans, the formation of sea ice results in a layer of highly saline water.

Global System

Students may think…

Instead of thinking…

Earth’s oceans are separate and not connected. Earth’s oceans are all connected and part of one global ocean system.
Oceans are unrelated to weather. Oceans play an important role in both climate and weather patterns.

Ocean Life

Students may think…

Instead of thinking…

Nothing (or very little) lives in polar oceans. Both the Arctic and Southern Oceans have surprisingly rich food webs. Many species are still undiscovered.
Coral reefs are found in all oceans. Corals are typically found in tropical and subtropical waters. They have very specific needs in terms of temperature, water salinity, and light.
Nothing lives in the middle of the ocean. Many organisms make up the food webs of the pelagic zone – the open water of the ocean. Animals and plankton also move throughout the water.

Sea Ice and Icebergs

Students may think…

Instead of thinking…

Melting sea ice causes (or will cause) sea level to rise. Sea ice is already floating, so melting sea ice will not cause sea-level rise.
Icebergs are made of saltwater. Most icebergs are made from calving glaciers. They are made of freshwater.

Humans and the Oceans

Students may think…

Instead of thinking…

The ocean is infinite so pollution is not a problem. Pollution is a problem everywhere. In the ocean, pollution can affect the entire food chain. Tiny creatures such as plankton take in pollutants, which are passed on to the larger animals that feed on them. The effects of the pollution are most visible in the top predators in a food web, as they end up with the highest level of pollutants from their prey.
The oceans’ resources are limitless. Like all other natural resources, those of the ocean are limited and must be conserved.
My personal actions don’t impact the oceans. Many of our actions eventually impact the oceans in terms of surface runoff and pollution.


Many of these misconceptions are developmental in nature (due to elementary students’ limited reasoning skills) or the result of lack of exposure to scientific content. Teachers may choose to assess student understanding simply through directed discussion and the use of leading questions. Student ideas about the ocean floor and the distribution of marine organisms may also be assessed by having students draw and label a cross-section view of an ocean. An informal conversation about a student’s drawing may provide great insight into his or her understanding.


The Ocean Literacy Network has developed concept flow diagrams for each of its seven essential principles. Divided into K-2, 3-5, 6-8, and 9-12 grade bands, these flow charts may be a helpful starting point for planning instruction.

Ocean Literacy Concept Flow Diagrams
These diagrams (pdf documents) show concepts that should be taught in four grade bands (K-2, 3-5, 6-8, and 9-12) to promote ocean literacy among all students.

We’ve included many lesson plans and activities in our article “Hands-on Lessons and Activities about the Ocean.” In addition, here are a few ideas for promoting correct scientific understanding among your students:

  • Make models of the seafloor – include ridges, mountain ranges, and canyons.

The Ocean Floor – Science
Students create a visual representation of seafloor features.

  • Use video clips to provide “first person” experiences.

Sea Creatures
This video clip from the Teachers’ Domain collection introduces students to unusual deep sea creatures.

  • Seek out children’s literature that provides information about more than just the familiar ocean creatures.
  • Study runoff and how waste products can end up in the ocean.

Oatmeal Runoff Activity
Students use oatmeal to simulate the effects of runoff in streams. Teachers can extend this lesson to include the effects of runoff on oceans.

  • Study marine food webs to learn how pollution impacts the entire ecosystem.

Ocean Pollution Unit Plan
A 15-lesson unit for upper elementary students focusing on the various types of ocean pollution and how we can prevent it.


Assessing and targeting student misconceptions about oceans can meet the Life Science and Earth and Space Science Content Standards for grades K-4 and 5-8 of the National Science Education Standards. The entire National Science Education Standards document can be read online or downloaded for free from the National Academies Press web site. Science Content Standards can be found in Chapter 6.

This article was written by Jessica Fries-Gaither. For more information, see the Contributors page. Email Kimberly Lightle, Principal Investigator, with any questions about the content of this site.

Copyright May 2009 – The Ohio State University. This material is based upon work supported by the National Science Foundation under Grant No. 0733024. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation. This work is licensed under an Attribution-ShareAlike 3.0 Unported Creative Commons license.

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