Vernier Software and Technology
Vernier Software & Technology

Investigating Salinity

Figure from experiment 7 from Investigating Environmental Science through Inquiry


Salinity is a measurement of the saltiness or concentration of salt in water. Ocean water contains many different salts, but the most abundant is sodium chloride, also know as table salt. Sodium chloride accounts for about 86% of all the ions present in ocean water. Other salts that can be found in ocean water at significant levels are calcium chloride and magnesium chloride.

While the average salinity of ocean water is 35 ppt (parts per thousand) of salt dissolved in water, there are several factors that can increase or decrease its salinity. At the polar regions, freezing of ocean water increases the salinity of the surrounding water. Evaporation in hot, arid regions also increases the salinity. The Dead Sea, located in Israel, has salinity nearly seven times that of most ocean water. At the ocean’s surface, rain, snow, and melting ice are all responsible for decreasing the salinity. As rivers enter the ocean, they carry large volumes of fresh water into the ocean, causing salinity to decrease.


In the Preliminary Activity, you will gain experience using a Conductivity Probe while determining the salinity of a saltwater sample provided by your teacher.

After completing the Preliminary Activity, you will first use reference sources to find out more about salinity before you choose and investigate a researchable question dealing with that subject.

Sensors and Equipment

This investigation features the following Vernier sensors and equipment.

Additional Requirements

You may also need an interface and software for data collection. What do I need for data collection?

Standards Correlations

See all standards correlations for Investigating Environmental Science through Inquiry »

Investigation 7 from Investigating Environmental Science through Inquiry Lab Book

<em>Investigating Environmental Science through Inquiry</em> book cover

Included in the Lab Book

Vernier lab books include word-processing files of the student instructions, essential teacher information, suggested answers, sample data and graphs, and more.

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