Investigation: Salinity of our local waters

Instructions / How to do this investigation

1. Choose a body of salt water with an access point that you can repeat accurately.
2. Take a baseline reading of salinity on a day after a day when there was NO rain.
3. Collect water by wading into the chosen location until the water depth is 30 cm. Use a small glass jar (~75 mL) and plunge downward into the water and lift up.
4. Measure salinity using a refractometer and record on site during your field day with students. After that, water samples are to be collected by an adult the day after it rained and brought back to the classroom where the students then measure salinity.
5. Record time of collection, time from the last high tide or low tide during each sample time. 
6. Record precipitation data by using a local weather station’s data.