Seawater Mining

Mathieu Richaud
California State University, Fresno, Earth & Environmental Sciences
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Initial Publication Date: May 15, 2019


Students use a Google Sheets filled with elemental seawater composition names and data. One of the goals is to find the answer to the question "How many pounds of gold are present in 1 cubic mile of seawater?"

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Learning Goals

Students should learn that the ocean volume, be it in liters or gallons, is an astronomical number, that there are many metals dissolved in the ocean, and that the quantities can be quite large. There is computation and data analysis involved, though the steps are well outlined. Data is from published resources. The skills developed in the activity is the use of a spreadsheet.

Context for Use

I teach this class activity at California State University, Fresno to primarily non-science juniors/seniors. Class size is about 45-50 students. This is an in-class activity taught after introduced the concept of salinity during an oceanography class. Students with little mastery of a spreadsheet program and with little maths skills took the best part of 30 minutes.

Description and Teaching Materials

I created a Google Sheets spreadsheet that can easily be shared with the class and copied by each student group into their own Google Drive, leaving the original spreadsheet untouched for future use.
Spreadsheet for the seawater mining activity ( 18kB May2 19)

Teaching Notes and Tips

The common area of confusion is whether or not a value should be divided or multiplied to go to the next step. For instance, to go from milligrams to metric ton, some students asked me if they had to multiply or divide the original cell by the conversion factor.


If students find the right amount of gold and have used equations using the equal sign (=) before typing the formula referencing cells with each other, I know that the assignment is complete.

References and Resources