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How to Track Salt Water

Tracking salt water is an interesting science project for students that has many practical applications in a variety of settings. In areas where rivers meet oceans, the salt front can be tracked. The salt front is the area on surface of a body of water where fresh water becomes salt water. There are many factors which can cause the salt-water concentration to increase or decrease. Heavy rains dilute the salt concentration and increase the proportion of fresh water. Evaporation, by contrast, increases the level of salt in water while dry spells increase the concentration of salt in bodies of water.

Things You'll Need

Pocket-size salinity meter
Water sampling containers with covers
Labels for containers
Small magic marker
Chart
Pencil

Instructions

- 1
  Collect water samples by dipping a small container into the water that you are testing. If you are tracking water in the ocean, river or other large body of water, collect your samples from the surface of the water. Fill the container halfway with water.
- 2
  Cap the container and record the location from where the sample was taken (for example, how many miles or feet from the mouth of the river the sample was taken and in what direction, such as "2 feet north").
- 3
  Remove the protective cap from your salinity meter and turn on the meter. Immerse the electrodes of the meter into the sample up to 25 mm and gently swirl the meter, making sure the electrodes are immersed while testing.
- 4
  Wait several seconds for the display value to equilibrize. Read and record the value of the meter reading. Convert the meter reading into the desired unit measurement.
- 5
  Wash off the electrodes and lower part of the meter with fresh water and repeat the measurement process for all of the samples.
- 6
  Note at which point the readings reach 100 mg of salt-per-liter. Water that reaches this level is considered salt water. If you take your measurements on a river, estuary or ocean front, you will be able to determine where the salt water front is located.

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