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The materials required for this science fair project:

-    A set of diving gear
-    An experienced diver
-    20 empty bottles, approximately 100ml each, to be used to collect water samples
-    Adequate supply of pH paper
-    a turbidity meter (these are pricey and you should therefore try to gain access to one from a test lab, or alternatively, check if your local utilities board is able to help with the testing. Handheld units start at several hundred dollars.)
-    1 freshwater test kit (these are inexpensive and may even be purchased online, from NexTag or other large retailers)
-    1 marker pen (waterproof ink)


1.    For this science fair project, the independent variable is the depth at which the water sample is taken i.e. 1 meter, 2 meters, 3 meters and 4 meters. The dependent variables are the pH reading, turbidity, ammonia content and the nitrate content of the water sample. This is determined by using pH paper, the turbidity meter and the freshwater test kit.. The constants (control variables) are the amount of water taken and the depth at which the water samples were obtained.

2.    You will need the scuba diver to gather the water samples  at 4 different depths. The diver will probably have the experience to help you identify a suitable lake with depths up to 4 meters, rent a boat and rent the appropriate diving gear.

3.    On the chosen day, a trip is made with the diver to the suitable diving spot. Ensure that safety procedures are properly followed and life jackets should be worn at the appropriate time,  The 4 bottles are labeled “1 meter”, “2 meters”, “3 meters” and “4 meters”. You can either use a labeller that prints on waterproof tape, or alternatively you can write directly onto the bottles with a waterproof marker. The diver will dive into the lake and obtain water samples from the required 4 different depths. Ensure that he collects 20 samples at each depth, from different locations within the lake.

4.    Collect the bottle samples from the diver and visually inspect the water in the bottles. Ensure that the marking on the bottles are  still clear.

5.    The 20 bottles of water samples are to be brought back to a lab for testing. They are tested for acidity with the pH paper and the turbidity meter will be used to test the turbidity of the water. The fresh water test kit will be used to check for levels of nitrate and ammonia. The results of the tests are recorded in the table below.

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Complexity level:
Project cost ($):
Time required:
1 day to prepare, 1 day for observation
Material availability:
Access to laboratory equipment
Safety concerns:

Scuba diving safety protocols and water safety measures to be strictly observed at all times. Should be performed only by an experienced adult.