The water sampling protocol is the first in a series of eight hydrology protocols:

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5th Grade and Up Estimated Time: 10 minutes

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The purpose of the Water Sampling Method is to teach students how to safely collect a water sample that is most indicative of the water found in that specific body of water. Students must not use distilled water to clean the bucket, or use a bucket that has been previously used for cleaning purpose, as this will affect the water sampling results. If students can safely reach the body of water, they can measure water temperature, pH, dissolved oxygen, and electrical conductivity in situ, directly at the water’s edge. Step 1 - Preparing the Bucket Lower the bucket into the body of water using the rope until it has partially filled with water. After the bucket is partially full, students can retrieve the bucket and swirl the water around to clean out the bucket. After this is done, students must repeat the process. Step 2 - Retrieving the Sample Students should always be sure to take a sample from the top surface of the water and be careful not to stir up bottom sediment or muddy the sample when pulling the bucket into shore. If students are sampling from a lake, bay or the ocean, they should throw the bucket out as far as possible. When tossing the bucket out into the lake students can use a pendulum action to create momentum with the rope. When hauling the bucket back in, students should lean out their arm like a crane and pull the sample bucket straight up and out of the lake.

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4-L bucket with a strong rope attached securely to the handle Paper towels 500 mL-polyethylene sample bottles GLOBE Science Notebooks, pens, Data Work Sheet Latex gloves (recommended)

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Safety note: Students and teachers should take great precaution regarding slippery lake edges. Teachers should ideally pick a sampling site that is shallow far beyond the water’s edge. Students should also practice the bucket toss on the open grass before performing it near the water. As a final precaution, the student picked for retrieving the water sample should know how to swim.

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1) A student creates a pendulum effect in order to cast the bucket out as far as possible. 2) A student aims to retrieve the top surface of the water sample. 3) The student uses his arm like a crane to retrieve the sample bucket without picking up any bottom sediment. 4) A student checks to make sure that the water sample has not been muddied during retrieval. Click here to view QuickTime movie of protocol!

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